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Selecting An Appropriate Bolt
I had a bit of an adventure when one of the two handlebar-fixing bolts
on my Deda Murex quilled stem decided to snap with a rather impressive cracking noise. I somehow didn't crash and happened to be only about seven miles from home. I got slowly home holding the stem with one hand and one of the brake levers on the dangling handlebars with the other hand. (This is not recommended to the reader.) I see that the bolt is a M6x18 tapered cone head Allen cap screw with pressed-on washer. The stem is two months shy of 15 years old, but I don't want to have this happen again. Looking on eBay, I see quite a few appropriate bolts, but I'm not sure what is optimal. Can anyone help? Everything seems to be Grade 5. Is that safe enough, or do I really want to (somehow) find Grade 8? Many are titanium. Is that a better choice than the more-common steel? Or should I look for stainless steel? I am always happy to save a few grams, but not if that's a significant risk. Advice welcome! Art |
Selecting An Appropriate Bolt
On Thu, 13 Apr 2017 20:07:48 -0700, Art Shapiro
wrote: I had a bit of an adventure when one of the two handlebar-fixing bolts on my Deda Murex quilled stem decided to snap with a rather impressive cracking noise. I somehow didn't crash and happened to be only about seven miles from home. I got slowly home holding the stem with one hand and one of the brake levers on the dangling handlebars with the other hand. (This is not recommended to the reader.) I see that the bolt is a M6x18 tapered cone head Allen cap screw with pressed-on washer. The stem is two months shy of 15 years old, but I don't want to have this happen again. Looking on eBay, I see quite a few appropriate bolts, but I'm not sure what is optimal. Can anyone help? Everything seems to be Grade 5. Is that safe enough, or do I really want to (somehow) find Grade 8? Many are titanium. Is that a better choice than the more-common steel? Or should I look for stainless steel? I am always happy to save a few grams, but not if that's a significant risk. Advice welcome! Art Grade 5 bolts should certainly be strong enough to hold the handle bars on. But there are grades 8 or 9 that are stronger. As an aside your description is incorrect. It might be an U.S. size which might be 8-32 or it might be metric in which case it would be M8-1.25 or maybe M8-1.0. A U.S. #8 bolt is about half the thickness of a 8mm bolt. Generally speaking stainless is no stronger than mild steel and Titanium is about the same strength as steel of the same hardness. stainless, of course doesn't corrode much and titanium is about half the weight of steel. Your description of snapping sounds seems more like something that was under great tension.... like over torqued? Again an aside. The bolt(s) broke once in 15 years..... |
Selecting An Appropriate Bolt
On 4/13/2017 10:07 PM, Art Shapiro wrote:
I had a bit of an adventure when one of the two handlebar-fixing bolts on my Deda Murex quilled stem decided to snap with a rather impressive cracking noise. I somehow didn't crash and happened to be only about seven miles from home. I got slowly home holding the stem with one hand and one of the brake levers on the dangling handlebars with the other hand. (This is not recommended to the reader.) I see that the bolt is a M6x18 tapered cone head Allen cap screw with pressed-on washer. The stem is two months shy of 15 years old, but I don't want to have this happen again. Looking on eBay, I see quite a few appropriate bolts, but I'm not sure what is optimal. Can anyone help? Everything seems to be Grade 5. Is that safe enough, or do I really want to (somehow) find Grade 8? Many are titanium. Is that a better choice than the more-common steel? Or should I look for stainless steel? I am always happy to save a few grams, but not if that's a significant risk. Advice welcome! Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. I wouldn't use Ti fasteners in a stem but some guys do and many don't die. Clean your handlebar, stem and and stem plate. Inspect for damage/cracks. Clean threads in the stem, inspect for damage, replace both bolts, lubricate at assembly, ensure the gap of the handlebar plate is even on both ends. Deda says torque to 10nm. Stand in front of your bike and put your full weight on the brake levers. Handlebar should not move. If it does or if anything seems awry in any way, replace the stem. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
Selecting An Appropriate Bolt
On 4/14/2017 5:35 AM, AMuzi wrote:
Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. How does one get these "readily available" Grade 8 guys? Deda doesn't seem to have much of a web presence outside of Italy. Is this a generic item stocked by a good LBS? Art |
Selecting An Appropriate Bolt
On 4/14/2017 9:14 AM, Art Shapiro wrote:
On 4/14/2017 5:35 AM, AMuzi wrote: Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. How does one get these "readily available" Grade 8 guys? Deda doesn't seem to have much of a web presence outside of Italy. Is this a generic item stocked by a good LBS? Any metric fastener supplier if not your local hardware store. https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
Selecting An Appropriate Bolt
On 4/14/2017 7:27 AM, AMuzi wrote:
Any metric fastener supplier if not your local hardware store. https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web Thanks. That search engine link appears to be for traditional cap head bolts rather than the original tapered cone head bolts. But I'll hit the drawers at a couple of the area hardware stores or big box stores and see what they have. Appreciated the input. Art |
Selecting An Appropriate Bolt
On Fri, 14 Apr 2017 18:15:25 +0700, John B Slocomb
wrote: On Thu, 13 Apr 2017 20:07:48 -0700, Art Shapiro wrote: I had a bit of an adventure when one of the two handlebar-fixing bolts on my Deda Murex quilled stem decided to snap with a rather impressive cracking noise. I somehow didn't crash and happened to be only about seven miles from home. I got slowly home holding the stem with one hand and one of the brake levers on the dangling handlebars with the other hand. (This is not recommended to the reader.) I see that the bolt is a M6x18 tapered cone head Allen cap screw with pressed-on washer. The stem is two months shy of 15 years old, but I don't want to have this happen again. Looking on eBay, I see quite a few appropriate bolts, but I'm not sure what is optimal. Can anyone help? Everything seems to be Grade 5. Is that safe enough, or do I really want to (somehow) find Grade 8? Many are titanium. Is that a better choice than the more-common steel? Or should I look for stainless steel? I am always happy to save a few grams, but not if that's a significant risk. Advice welcome! Art Grade 5 bolts should certainly be strong enough to hold the handle bars on. But there are grades 8 or 9 that are stronger. As an aside your description is incorrect. It might be an U.S. size which might be 8-32 or it might be metric in which case it would be M8-1.25 or maybe M8-1.0. A U.S. #8 bolt is about half the thickness of a 8mm bolt. Generally speaking stainless is no stronger than mild steel and Titanium is about the same strength as steel of the same hardness. stainless, of course doesn't corrode much and titanium is about half the weight of steel. Your description of snapping sounds seems more like something that was under great tension.... like over torqued? Again an aside. The bolt(s) broke once in 15 years..... The steel bolt may have been "necked down" by rust. Stainless doesn't do that - but often "welds" itself to the nut - particularly in high torque installations. |
Selecting An Appropriate Bolt
On Friday, April 14, 2017 at 7:27:06 AM UTC-7, AMuzi wrote:
On 4/14/2017 9:14 AM, Art Shapiro wrote: On 4/14/2017 5:35 AM, AMuzi wrote: Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. How does one get these "readily available" Grade 8 guys? Deda doesn't seem to have much of a web presence outside of Italy. Is this a generic item stocked by a good LBS? Any metric fastener supplier if not your local hardware store. https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web My neighborhood hardware store has them: http://aboysupply.com/wp-content/upl...1024x415_c.png They have a crazy selection of fasteners. By the way, what's the deal with thread pitch? I always worry I'm getting the wrong pitch, but I guess that the whole "standard/fine/extra fine" thread pitch only kicks in with fasteners over 8mm(?). Otherwise, it's a pre-set. Right? -- Jay Beattie. |
Selecting An Appropriate Bolt
On 4/14/2017 11:33 AM, jbeattie wrote:
On Friday, April 14, 2017 at 7:27:06 AM UTC-7, AMuzi wrote: On 4/14/2017 9:14 AM, Art Shapiro wrote: On 4/14/2017 5:35 AM, AMuzi wrote: Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. How does one get these "readily available" Grade 8 guys? Deda doesn't seem to have much of a web presence outside of Italy. Is this a generic item stocked by a good LBS? Any metric fastener supplier if not your local hardware store. https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web My neighborhood hardware store has them: http://aboysupply.com/wp-content/upl...1024x415_c.png They have a crazy selection of fasteners. By the way, what's the deal with thread pitch? I always worry I'm getting the wrong pitch, but I guess that the whole "standard/fine/extra fine" thread pitch only kicks in with fasteners over 8mm(?). Otherwise, it's a pre-set. Right? There are/were indeed other pitches available (the French metric m5x0.9 for example) but the DIN standard (m5x0.8, m6x1 etc) is well established now. In my experience that's more of a problem with SAE fasteners (1/4-20, 1/4-28 etc). Prior systems such as AC/AF, UNC/UNF, Whitworth have become rare and unusual. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
Selecting An Appropriate Bolt
On Friday, April 14, 2017 at 10:07:57 AM UTC-7, AMuzi wrote:
On 4/14/2017 11:33 AM, jbeattie wrote: On Friday, April 14, 2017 at 7:27:06 AM UTC-7, AMuzi wrote: On 4/14/2017 9:14 AM, Art Shapiro wrote: On 4/14/2017 5:35 AM, AMuzi wrote: Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. How does one get these "readily available" Grade 8 guys? Deda doesn't seem to have much of a web presence outside of Italy. Is this a generic item stocked by a good LBS? Any metric fastener supplier if not your local hardware store. https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web My neighborhood hardware store has them: http://aboysupply.com/wp-content/upl...1024x415_c.png They have a crazy selection of fasteners. By the way, what's the deal with thread pitch? I always worry I'm getting the wrong pitch, but I guess that the whole "standard/fine/extra fine" thread pitch only kicks in with fasteners over 8mm(?). Otherwise, it's a pre-set. Right? There are/were indeed other pitches available (the French metric m5x0.9 for example) but the DIN standard (m5x0.8, m6x1 etc) is well established now. In my experience that's more of a problem with SAE fasteners (1/4-20, 1/4-28 etc). Prior systems such as AC/AF, UNC/UNF, Whitworth have become rare and unusual. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 I am horrified that anyone would need a Grade 8 bolt for a stem. I would get a stem that uses two stainless bolts to clamp to the steerer and four to clamp to the bar. I would assume that he is discussing an MTB because I can't imagine conditions bad enough on a road to pop a grade 8 bolt under any forces there. |
Selecting An Appropriate Bolt
On 4/14/2017 12:33 PM, jbeattie wrote:
On Friday, April 14, 2017 at 7:27:06 AM UTC-7, AMuzi wrote: On 4/14/2017 9:14 AM, Art Shapiro wrote: On 4/14/2017 5:35 AM, AMuzi wrote: Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. How does one get these "readily available" Grade 8 guys? Deda doesn't seem to have much of a web presence outside of Italy. Is this a generic item stocked by a good LBS? Any metric fastener supplier if not your local hardware store. https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web My neighborhood hardware store has them: http://aboysupply.com/wp-content/upl...1024x415_c.png They have a crazy selection of fasteners. By the way, what's the deal with thread pitch? I always worry I'm getting the wrong pitch, but I guess that the whole "standard/fine/extra fine" thread pitch only kicks in with fasteners over 8mm(?). Otherwise, it's a pre-set. Right? There are metric fine pitch threads https://mdmetric.com/tech/thddat3.htm like 5mm-0.5 instead of 5mm-0.8 but I've hardly ever come across them in real life. Fine thread fasteners are a bit stronger and more resistant to vibrating loose. But in most cases, you can solve both problems by other means - perhaps "next size up" and Loctite. -- - Frank Krygowski |
Selecting An Appropriate Bolt
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Selecting An Appropriate Bolt
On Friday, April 14, 2017 at 11:11:18 AM UTC-7, Frank Krygowski wrote:
On 4/14/2017 12:33 PM, jbeattie wrote: On Friday, April 14, 2017 at 7:27:06 AM UTC-7, AMuzi wrote: On 4/14/2017 9:14 AM, Art Shapiro wrote: On 4/14/2017 5:35 AM, AMuzi wrote: Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. How does one get these "readily available" Grade 8 guys? Deda doesn't seem to have much of a web presence outside of Italy. Is this a generic item stocked by a good LBS? Any metric fastener supplier if not your local hardware store. https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web My neighborhood hardware store has them: http://aboysupply.com/wp-content/upl...1024x415_c.png They have a crazy selection of fasteners. By the way, what's the deal with thread pitch? I always worry I'm getting the wrong pitch, but I guess that the whole "standard/fine/extra fine" thread pitch only kicks in with fasteners over 8mm(?). Otherwise, it's a pre-set. Right? There are metric fine pitch threads https://mdmetric.com/tech/thddat3.htm like 5mm-0.5 instead of 5mm-0.8 but I've hardly ever come across them in real life. Fine thread fasteners are a bit stronger and more resistant to vibrating loose. But in most cases, you can solve both problems by other means - perhaps "next size up" and Loctite. My concern was matching the pitch on threaded bosses -- and most recently wondering whether the 4mm button-head bolts I picked up at the hardware store had the right pitch. For some reason, Specialized decided to use 4mm bolts for the BB/bridge fender mounts on the Roubaix. Very odd. I didn't have any 4mm bolts lying around. -- Jay Beattie. |
Selecting An Appropriate Bolt
On 4/14/2017 7:44 PM, jbeattie wrote:
For some reason, Specialized decided to use 4mm bolts for the BB/bridge fender mounts on the Roubaix. Very odd. I didn't have any 4mm bolts lying around. That does seem like an odd decision. M5x0.8 has been so normal for so long. What, were they hoping to save half a gram?? It's like the bicycle industry employs specialists whose job it is to destroy standardization. -- - Frank Krygowski |
Selecting An Appropriate Bolt
On Fri, 14 Apr 2017 07:14:19 -0700, Art Shapiro
wrote: On 4/14/2017 5:35 AM, AMuzi wrote: Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. How does one get these "readily available" Grade 8 guys? Deda doesn't seem to have much of a web presence outside of Italy. Is this a generic item stocked by a good LBS? Art There are a great number of mail order companies who can supply the bolts you need. The taper head is a matter of "what looks pretty" and no not strength. I'm not necessarily recommending them but peruse the McMaster-Carr web site for available bolts. Or you could probably contact Andrew Muzi, our resident bicycle parts specialist :-) |
Selecting An Appropriate Bolt
On Fri, 14 Apr 2017 19:50:58 -0400, Frank Krygowski
wrote: On 4/14/2017 7:44 PM, jbeattie wrote: For some reason, Specialized decided to use 4mm bolts for the BB/bridge fender mounts on the Roubaix. Very odd. I didn't have any 4mm bolts lying around. That does seem like an odd decision. M5x0.8 has been so normal for so long. What, were they hoping to save half a gram?? It's like the bicycle industry employs specialists whose job it is to destroy standardization. Or maybe their procurement department got a really, really, great deal on 4mm bolts -) What's the old theory? ""Never attribute to malice that which is adequately explained by stupidity"? |
Selecting An Appropriate Bolt
On Friday, April 14, 2017 at 4:15:34 AM UTC-7, John B Slocomb wrote:
On Thu, 13 Apr 2017 20:07:48 -0700, Art Shapiro wrote: I had a bit of an adventure when one of the two handlebar-fixing bolts on my Deda Murex quilled stem decided to snap with a rather impressive cracking noise. I somehow didn't crash and happened to be only about seven miles from home. I got slowly home holding the stem with one hand and one of the brake levers on the dangling handlebars with the other hand. (This is not recommended to the reader.) I see that the bolt is a M6x18 tapered cone head Allen cap screw with pressed-on washer. The stem is two months shy of 15 years old, but I don't want to have this happen again. Looking on eBay, I see quite a few appropriate bolts, but I'm not sure what is optimal. Can anyone help? Everything seems to be Grade 5. Is that safe enough, or do I really want to (somehow) find Grade 8? Many are titanium. Is that a better choice than the more-common steel? Or should I look for stainless steel? I am always happy to save a few grams, but not if that's a significant risk. Advice welcome! Art Grade 5 bolts should certainly be strong enough to hold the handle bars on. But there are grades 8 or 9 that are stronger. What makes you say this? Do you have some #s to back this statement up, or is it just your wild guess? Have you calculated the load on this part when when a rider of a given weight hits a pothole at a given speed, or ??? And more importantly, why skimp here? As an aside your description is incorrect. It might be an U.S. size which might be 8-32 or it might be metric in which case it would be M8-1.25 or maybe M8-1.0. A U.S. #8 bolt is about half the thickness of a 8mm bolt. Huh?!? What are you on about? It is you who is incorrect not he. He said it was an M6x18. The x is pronounced "by". Put M6x18 in google and click images. You will see M6 bolts in an 18mm length. He chose to identify the bolt by it's diameter and length, just like the rest of the world does most of the time. You are describing bolts using diameter and pitch. This is incomplete, as it does not specify the length. Further is is irrelevant since the JIS and ISO standards both specify 1.0 as the standard pitch for 6mm bolts. It is not an 8-32, nor is it an 8mm. Both of these suggestions are ridiculous. It is an M6x18 and while fine m6 bolts do exist in 1.10 pitch they are not common and it is safe to say it is, in this application, almost undoubtedly a 1.0. You seem to have latched on the number 8 for some reason. Generally speaking stainless is no stronger than mild steel and Titanium is about the same strength as steel of the same hardness. stainless, of course doesn't corrode much and titanium is about half the weight of steel. Steel has or can have greater strength for a given diameter. Why skimp here? Again an aside. The bolt(s) broke once in 15 years..... Looking at it the other way, it already broke once. Furthermore some possible reasons e.g. (e.g. over-tightening) might have also affected the threads that the bolt went into. The stem is two months shy of 15 years old, but I don't want to have this happen again. Get a new stem. This one is a flawed design. There is built-in problem with the shape of the part, and that is a lack of remaining metal around the bolt hole. The stem has been made bigger around the front bolt hole to overcome this, but it still has the 2-bolt-1-failure problem. The traditional shape does not make this concession to ease-of-handlebar-change, and carefully places the single bolt in the rear where there is plenty of metal surrounding the threads. The traditional design is both less likely to experience a bolt failure, and - in the wild guess dept., be more likely to hold on to the bars and remain usable in the event that one does. Deda Murex 2-bolt: https://www.google.com/search?q=deda...f3AGoQ_AUIBygC 3ttt traditional: https://www.google.com/search?q=3ttt...w=1306&bih=724 |
Selecting An Appropriate Bolt
On Mon, 17 Apr 2017 13:52:56 -0700 (PDT), Doug Landau
wrote: On Friday, April 14, 2017 at 4:15:34 AM UTC-7, John B Slocomb wrote: On Thu, 13 Apr 2017 20:07:48 -0700, Art Shapiro wrote: I had a bit of an adventure when one of the two handlebar-fixing bolts on my Deda Murex quilled stem decided to snap with a rather impressive cracking noise. I somehow didn't crash and happened to be only about seven miles from home. I got slowly home holding the stem with one hand and one of the brake levers on the dangling handlebars with the other hand. (This is not recommended to the reader.) I see that the bolt is a M6x18 tapered cone head Allen cap screw with pressed-on washer. The stem is two months shy of 15 years old, but I don't want to have this happen again. Looking on eBay, I see quite a few appropriate bolts, but I'm not sure what is optimal. Can anyone help? Everything seems to be Grade 5. Is that safe enough, or do I really want to (somehow) find Grade 8? Many are titanium. Is that a better choice than the more-common steel? Or should I look for stainless steel? I am always happy to save a few grams, but not if that's a significant risk. Advice welcome! Art Grade 5 bolts should certainly be strong enough to hold the handle bars on. But there are grades 8 or 9 that are stronger. What makes you say this? Do you have some #s to back this statement up, or is it just your wild guess? Have you calculated the load on this part when when a rider of a given weight hits a pothole at a given speed, or ??? And more importantly, why skimp here? As an aside your description is incorrect. It might be an U.S. size which might be 8-32 or it might be metric in which case it would be M8-1.25 or maybe M8-1.0. A U.S. #8 bolt is about half the thickness of a 8mm bolt. Huh?!? What are you on about? It is you who is incorrect not he. He said it was an M6x18. The x is pronounced "by". Put M6x18 in google and click images. You will see M6 bolts in an 18mm length. He chose to identify the bolt by it's diameter and length, just like the rest of the world does most of the time. You are describing bolts using diameter and pitch. This is incomplete, as it does not specify the length. Further is is irrelevant since the JIS and ISO standards both specify 1.0 as the standard pitch for 6mm bolts. It is not an 8-32, nor is it an 8mm. Both of these suggestions are ridiculous. It is an M6x18 and while fine m6 bolts do exist in 1.10 pitch they are not common and it is safe to say it is, in this application, almost undoubtedly a 1.0. You seem to have latched on the number 8 for some reason. An M6X10 is the metric "functional equivalent" of a 1/4" UNC bolt. It's dimensions and strength are very close. Being a metric bolt it will be neither a Grade 5 nor a Grade 8. - it will be a class 8.8 or 10.9 or 12.9 An 8.8 is the metric "functional equivalent" to a grade 5 |
Selecting An Appropriate Bolt
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Selecting An Appropriate Bolt
On Friday, April 14, 2017 at 11:11:18 AM UTC-7, Frank Krygowski wrote:
On 4/14/2017 12:33 PM, jbeattie wrote: On Friday, April 14, 2017 at 7:27:06 AM UTC-7, AMuzi wrote: On 4/14/2017 9:14 AM, Art Shapiro wrote: On 4/14/2017 5:35 AM, AMuzi wrote: Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. How does one get these "readily available" Grade 8 guys? Deda doesn't seem to have much of a web presence outside of Italy. Is this a generic item stocked by a good LBS? Any metric fastener supplier if not your local hardware store. https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web My neighborhood hardware store has them: http://aboysupply.com/wp-content/upl...1024x415_c.png They have a crazy selection of fasteners. By the way, what's the deal with thread pitch? I always worry I'm getting the wrong pitch, but I guess that the whole "standard/fine/extra fine" thread pitch only kicks in with fasteners over 8mm(?). Otherwise, it's a pre-set. Right? No. It's just the charts that only kick in at 8. They are clearly both a)written by someone who doesn't actually know, themselves, and b)plagarising heavily from each other, and repeating the other's mistakes. There are metric fine pitch threads https://mdmetric.com/tech/thddat3.htm like 5mm-0.5 instead of 5mm-0.8 That chart is ****ed up. It says fine but lists more than one thread pitch in the first column, and inconsistently shows extra- and super-fine pitches instead. The commonly found standard M5 bolt is indeed 0.8 pitch, but the commonly found fine pitch M5 is 0.7. 0.5 must be extra-fine or super-fine. Which is why when you buy a tap and dies set it comes with 5-.8 and 5-.7 but not 5-.5. I think but am not 100% sure that M6 fine is 0.8 not 0.75. http://www.sears.com/craftsman-39-pc...g&gclsrc=aw.ds but I've hardly ever come across them in real life. No? Are you sure - you've never chased munged up pedal threads? Doing so sends you down to the hardware store for an M10-1.0 tap, because your tap and dies set comes with a 10-1.5 (standard) and 10-1.25 (fine). There is at least one other place where there is a fine thread, an 8, I think, and I think it's the brake pivot bolt, but am not sure I'm remembering correctly. What's the thread pitch of derailer hangers? |
Selecting An Appropriate Bolt
On 4/17/2017 6:19 PM, Doug Landau wrote:
On Friday, April 14, 2017 at 11:11:18 AM UTC-7, Frank Krygowski wrote: On 4/14/2017 12:33 PM, jbeattie wrote: On Friday, April 14, 2017 at 7:27:06 AM UTC-7, AMuzi wrote: On 4/14/2017 9:14 AM, Art Shapiro wrote: On 4/14/2017 5:35 AM, AMuzi wrote: Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. How does one get these "readily available" Grade 8 guys? Deda doesn't seem to have much of a web presence outside of Italy. Is this a generic item stocked by a good LBS? Any metric fastener supplier if not your local hardware store. https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web My neighborhood hardware store has them: http://aboysupply.com/wp-content/upl...1024x415_c.png They have a crazy selection of fasteners. By the way, what's the deal with thread pitch? I always worry I'm getting the wrong pitch, but I guess that the whole "standard/fine/extra fine" thread pitch only kicks in with fasteners over 8mm(?). Otherwise, it's a pre-set. Right? No. It's just the charts that only kick in at 8. They are clearly both a)written by someone who doesn't actually know, themselves, and b)plagarising heavily from each other, and repeating the other's mistakes. There are metric fine pitch threads https://mdmetric.com/tech/thddat3.htm like 5mm-0.5 instead of 5mm-0.8 That chart is ****ed up. It says fine but lists more than one thread pitch in the first column, and inconsistently shows extra- and super-fine pitches instead. The commonly found standard M5 bolt is indeed 0.8 pitch, but the commonly found fine pitch M5 is 0.7. 0.5 must be extra-fine or super-fine. Which is why when you buy a tap and dies set it comes with 5-.8 and 5-.7 but not 5-.5. I think but am not 100% sure that M6 fine is 0.8 not 0.75. http://www.sears.com/craftsman-39-pc...g&gclsrc=aw.ds but I've hardly ever come across them in real life. No? Are you sure - you've never chased munged up pedal threads? Doing so sends you down to the hardware store for an M10-1.0 tap, because your tap and dies set comes with a 10-1.5 (standard) and 10-1.25 (fine). There is at least one other place where there is a fine thread, an 8, I think, and I think it's the brake pivot bolt, but am not sure I'm remembering correctly. What's the thread pitch of derailer hangers? Pedals are 9/16"-20tpi. The older metric format was m14x1.25 (now abandoned) and there are 1/2"-20 for steel OPC. Modern gear tabs are m10x1. Campagnolo changed from 10f26 (WW 55deg) in 1999. Sidepull pivot bolts are mostly m6x1.0 but outliers include Zeus 2001 with fine m6x0.75. There are (were) others but as I noted they are outliers. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
Selecting An Appropriate Bolt
On Monday, April 17, 2017 at 5:50:28 PM UTC-7, AMuzi wrote:
On 4/17/2017 6:19 PM, Doug Landau wrote: On Friday, April 14, 2017 at 11:11:18 AM UTC-7, Frank Krygowski wrote: On 4/14/2017 12:33 PM, jbeattie wrote: On Friday, April 14, 2017 at 7:27:06 AM UTC-7, AMuzi wrote: On 4/14/2017 9:14 AM, Art Shapiro wrote: On 4/14/2017 5:35 AM, AMuzi wrote: Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. How does one get these "readily available" Grade 8 guys? Deda doesn't seem to have much of a web presence outside of Italy. Is this a generic item stocked by a good LBS? Any metric fastener supplier if not your local hardware store. https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web My neighborhood hardware store has them: http://aboysupply.com/wp-content/upl...1024x415_c.png They have a crazy selection of fasteners. By the way, what's the deal with thread pitch? I always worry I'm getting the wrong pitch, but I guess that the whole "standard/fine/extra fine" thread pitch only kicks in with fasteners over 8mm(?). Otherwise, it's a pre-set. Right? No. It's just the charts that only kick in at 8. They are clearly both a)written by someone who doesn't actually know, themselves, and b)plagarising heavily from each other, and repeating the other's mistakes. There are metric fine pitch threads https://mdmetric.com/tech/thddat3.htm like 5mm-0.5 instead of 5mm-0.8 That chart is ****ed up. It says fine but lists more than one thread pitch in the first column, and inconsistently shows extra- and super-fine pitches instead. The commonly found standard M5 bolt is indeed 0.8 pitch, but the commonly found fine pitch M5 is 0.7. 0.5 must be extra-fine or super-fine. Which is why when you buy a tap and dies set it comes with 5-.8 and 5-.7 but not 5-.5. I think but am not 100% sure that M6 fine is 0.8 not 0.75. http://www.sears.com/craftsman-39-pc...g&gclsrc=aw.ds but I've hardly ever come across them in real life. No? Are you sure - you've never chased munged up pedal threads? Doing so sends you down to the hardware store for an M10-1.0 tap, because your tap and dies set comes with a 10-1.5 (standard) and 10-1.25 (fine). There is at least one other place where there is a fine thread, an 8, I think, and I think it's the brake pivot bolt, but am not sure I'm remembering correctly. What's the thread pitch of derailer hangers? Pedals are 9/16"-20tpi. The older metric format was m14x1.25 (now abandoned) and there are 1/2"-20 for steel OPC. Modern gear tabs are m10x1. Campagnolo changed from 10f26 (WW 55deg) in 1999. Sidepull pivot bolts are mostly m6x1.0 but outliers include Zeus 2001 with fine m6x0.75. There are (were) others but as I noted they are outliers. OK, guess i was rembering derailer hangars http://www.parktool.com/product/frame-tap-tap-10 |
Selecting An Appropriate Bolt
On 4/17/2017 7:19 PM, Doug Landau wrote:
On Friday, April 14, 2017 at 11:11:18 AM UTC-7, Frank Krygowski wrote: There are metric fine pitch threads https://mdmetric.com/tech/thddat3.htm like 5mm-0.5 instead of 5mm-0.8 That chart is ****ed up. It says fine but lists more than one thread pitch in the first column, and inconsistently shows extra- and super-fine pitches instead. I could have walked downstairs and opened my Machinery's Handbook but didn't bother. As I said, I've hardly ever come across fine pitch metric threads in real life. I was simply giving evidence that they exist. but I've hardly ever come across them in real life. No? Are you sure - you've never chased munged up pedal threads? Actually, no, I don't think I ever have. Doing so sends you down to the hardware store for an M10-1.0 tap, because your tap and dies set comes with a 10-1.5 (standard) and 10-1.25 (fine). As Andrew says, my pedal threads are all 9/16", except for some kid bike steel cranks. Andrew says 20 tpi, and I'll trust him. I've never bothered to check. -- - Frank Krygowski |
Selecting An Appropriate Bolt
On Mon, 17 Apr 2017 16:19:15 -0700 (PDT), Doug Landau
wrote: On Friday, April 14, 2017 at 11:11:18 AM UTC-7, Frank Krygowski wrote: On 4/14/2017 12:33 PM, jbeattie wrote: On Friday, April 14, 2017 at 7:27:06 AM UTC-7, AMuzi wrote: On 4/14/2017 9:14 AM, Art Shapiro wrote: On 4/14/2017 5:35 AM, AMuzi wrote: Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. How does one get these "readily available" Grade 8 guys? Deda doesn't seem to have much of a web presence outside of Italy. Is this a generic item stocked by a good LBS? Any metric fastener supplier if not your local hardware store. https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web My neighborhood hardware store has them: http://aboysupply.com/wp-content/upl...1024x415_c.png They have a crazy selection of fasteners. By the way, what's the deal with thread pitch? I always worry I'm getting the wrong pitch, but I guess that the whole "standard/fine/extra fine" thread pitch only kicks in with fasteners over 8mm(?). Otherwise, it's a pre-set. Right? No. It's just the charts that only kick in at 8. They are clearly both a)written by someone who doesn't actually know, themselves, and b)plagarising heavily from each other, and repeating the other's mistakes. There are metric fine pitch threads https://mdmetric.com/tech/thddat3.htm like 5mm-0.5 instead of 5mm-0.8 That chart is ****ed up. It says fine but lists more than one thread pitch in the first column, and inconsistently shows extra- and super-fine pitches instead. The commonly found standard M5 bolt is indeed 0.8 pitch, but the commonly found fine pitch M5 is 0.7. 0.5 must be extra-fine or super-fine. Which is why when you buy a tap and dies set it comes with 5-.8 and 5-.7 but not 5-.5. I think but am not 100% sure that M6 fine is 0.8 not 0.75. http://www.sears.com/craftsman-39-pc...g&gclsrc=aw.ds but I've hardly ever come across them in real life. No? Are you sure - you've never chased munged up pedal threads? Doing so sends you down to the hardware store for an M10-1.0 tap, because your tap and dies set comes with a 10-1.5 (standard) and 10-1.25 (fine). There is at least one other place where there is a fine thread, an 8, I think, and I think it's the brake pivot bolt, but am not sure I'm remembering correctly. What's the thread pitch of derailer hangers? The "fine thread - course thread" discussion if essentially a very simplistic categorizing of fasteners. The U.S. Unified thread system provides a sort of rationalization for a UNC/UNF series but that didn't and doesn't prevent fasteners being made in a large number of thread pitches. In U.S. sizes we have, for example, the 1/4"x20tpi (National Course), the 1/4 x 24 (NS), the 1/4 x 28 (NF), the 1/4 x 32 (NEF) and the 1/4 x 40 (NS). |
Selecting An Appropriate Bolt
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Selecting An Appropriate Bolt
On Tue, 18 Apr 2017 10:29:32 +0700, John B Slocomb
wrote: If you want to talk length then yes. A bolt should be long enough that one complete thread will be extend past the nut. but there is not maximum length, un less, or course it hits the other side of the automobile. This is not true with AN hardware.AN hardware is spec'd by it's diameter and grip length -and there is a stringent spec as to how much thread must/may extend beyond the nut. You NEVER have threads within the "grip" It is not an 8-32, nor is it an 8mm. Both of these suggestions are ridiculous. It is an M6x18 and while fine m6 bolts do exist in 1.10 pitch they are not common and it is safe to say it is, in this application, almost undoubtedly a 1.0. You seem to have latched on the number 8 for some reason. An M6X10 is the metric "functional equivalent" of a 1/4" UNC bolt. It's dimensions and strength are very close. Being a metric bolt it will be neither a Grade 5 nor a Grade 8. - it will be a class 8.8 or 10.9 or 12.9 An 8.8 is the metric "functional equivalent" to a grade 5 If you wish to be picky then let us be picky. There is no such thing as a M6X10 thread, and even if it existed it would hardly be equivalent to a 1/4-20 bolt. After all a 1 inch 1/4" bolt would have 20 threads on it while your imaginary M6X10 bolt would have only (roughly) 4. Probably have to tighten the nut real tight to get it to hold. I wonder can one even cut a 60 degree 10mm thread on a 6 mm rod? Who's being picky?? |
Selecting An Appropriate Bolt
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Selecting An Appropriate Bolt
On Tue, 18 Apr 2017 18:56:17 +0700, John B Slocomb
wrote: On Tue, 18 Apr 2017 00:08:14 -0400, wrote: On Tue, 18 Apr 2017 10:29:32 +0700, John B Slocomb wrote: If you want to talk length then yes. A bolt should be long enough that one complete thread will be extend past the nut. but there is not maximum length, un less, or course it hits the other side of the automobile. This is not true with AN hardware.AN hardware is spec'd by it's diameter and grip length -and there is a stringent spec as to how much thread must/may extend beyond the nut. You NEVER have threads within the "grip" Something must have changed with those AN people after the twenty years I spent fixing their airplanes because the "one thread past the nut" rule was certainly followed then. I've personally seen an Air Force Inspector turn down an installation because the bolt didn't protrude past the nut. (Which is likely why I remember it :-) You didn't read my whole post Slocumb. I was responding to the " but there is not maximum length, un less, or course it hits the other side of the automobile. AN bolts need to be the EXACT length required. No more than 2 washers allowes to adjust the protrusion of the thread through the nut. If it doesn't protrude OR protrudes too much it fails. (at least here in Canada) |
Selecting An Appropriate Bolt
On Monday, April 17, 2017 at 8:29:53 PM UTC-7, John B Slocomb wrote:
On Mon, 17 Apr 2017 17:51:39 -0400, wrote: On Mon, 17 Apr 2017 13:52:56 -0700 (PDT), Doug Landau wrote: On Friday, April 14, 2017 at 4:15:34 AM UTC-7, John B Slocomb wrote: On Thu, 13 Apr 2017 20:07:48 -0700, Art Shapiro wrote: I had a bit of an adventure when one of the two handlebar-fixing bolts on my Deda Murex quilled stem decided to snap with a rather impressive cracking noise. I somehow didn't crash and happened to be only about seven miles from home. I got slowly home holding the stem with one hand and one of the brake levers on the dangling handlebars with the other hand. (This is not recommended to the reader.) I see that the bolt is a M6x18 tapered cone head Allen cap screw with pressed-on washer. The stem is two months shy of 15 years old, but I don't want to have this happen again. Looking on eBay, I see quite a few appropriate bolts, but I'm not sure what is optimal. Can anyone help? Everything seems to be Grade 5. Is that safe enough, or do I really want to (somehow) find Grade 8? Many are titanium. Is that a better choice than the more-common steel? Or should I look for stainless steel? I am always happy to save a few grams, but not if that's a significant risk. Advice welcome! Art Grade 5 bolts should certainly be strong enough to hold the handle bars on. But there are grades 8 or 9 that are stronger. What makes you say this? Do you have some #s to back this statement up, or is it just your wild guess? Have you calculated the load on this part when when a rider of a given weight hits a pothole at a given speed, or ??? And more importantly, why skimp here? As an aside your description is incorrect. It might be an U.S. size which might be 8-32 or it might be metric in which case it would be M8-1.25 or maybe M8-1.0. A U.S. #8 bolt is about half the thickness of a 8mm bolt. Huh?!? What are you on about? It is you who is incorrect not he. He said it was an M6x18. The x is pronounced "by". Put M6x18 in google and click images. You will see M6 bolts in an 18mm length. He chose to identify the bolt by it's diameter and length, just like the rest of the world does most of the time. You are right. I'll change my reply to read "It might be an U.S. size which might be 6-32 or it might be metric in which case it would be M6-1.0. A U.S. #6 bolt is about half the thickness of a 6mm bolt." Happy now? Nope. Please return to the subject, and change your reply to answer the OP's question, which was "Everything seems to be Grade 5. Is that safe enough, or do I really want to (somehow) find Grade 8?" This will require first identifying the most extreme condition that the bolt will experience as long as the rider can hold on and stay upright. The goal is to determine safe enough, and one is not going to be safe after riding at cruising speed into a wall or curb anyway. Hitting a pothole seems reasonable to me, but whatever. Then calculate the tension on the bolt in that situation, and then compare that to specification for grade 8. But what is the value in stating "Grade 5 should certainly be strong enough to hold the bars on." ? So will a rubber band or some scotch tape, as long as one rides slow on smooth road. But there are grades 8 or 9 that are stronger Yes, the OP knows that, and had to to pose the question "Do I need grade 8?" in the first place. You are describing bolts using diameter and pitch. This is incomplete, as it does not specify the length. Further is is irrelevant since the JIS and ISO standards both specify 1.0 as the standard pitch for 6mm bolts. Nope. A thread is described by two things diameter and number of threads per unit. One can easily buy, for example, a 1/4" thread any where from a quarter of an inch long, or so, to three feet, or more. We are not talking about a thread. If you want to talk length then yes. Again the OP was talking about grade; you faulted him for the way he described the bolt, and I am saying that a)he described it in the same way we all do most of the time, which is not flawed, and b)the quality of this method which you say is a flaw also exists in your claim of what is correct. The fact is that a bolt has three identifying characteristics, and all must be expressed in order to avoid being incomplete, and at times, insufficient. |
Selecting An Appropriate Bolt
On Tue, 18 Apr 2017 14:15:09 -0700 (PDT), Doug Landau
wrote: On Monday, April 17, 2017 at 8:29:53 PM UTC-7, John B Slocomb wrote: On Mon, 17 Apr 2017 17:51:39 -0400, wrote: On Mon, 17 Apr 2017 13:52:56 -0700 (PDT), Doug Landau wrote: On Friday, April 14, 2017 at 4:15:34 AM UTC-7, John B Slocomb wrote: On Thu, 13 Apr 2017 20:07:48 -0700, Art Shapiro wrote: I had a bit of an adventure when one of the two handlebar-fixing bolts on my Deda Murex quilled stem decided to snap with a rather impressive cracking noise. I somehow didn't crash and happened to be only about seven miles from home. I got slowly home holding the stem with one hand and one of the brake levers on the dangling handlebars with the other hand. (This is not recommended to the reader.) I see that the bolt is a M6x18 tapered cone head Allen cap screw with pressed-on washer. The stem is two months shy of 15 years old, but I don't want to have this happen again. Looking on eBay, I see quite a few appropriate bolts, but I'm not sure what is optimal. Can anyone help? Everything seems to be Grade 5. Is that safe enough, or do I really want to (somehow) find Grade 8? Many are titanium. Is that a better choice than the more-common steel? Or should I look for stainless steel? I am always happy to save a few grams, but not if that's a significant risk. Advice welcome! Art Grade 5 bolts should certainly be strong enough to hold the handle bars on. But there are grades 8 or 9 that are stronger. What makes you say this? Do you have some #s to back this statement up, or is it just your wild guess? Have you calculated the load on this part when when a rider of a given weight hits a pothole at a given speed, or ??? And more importantly, why skimp here? As an aside your description is incorrect. It might be an U.S. size which might be 8-32 or it might be metric in which case it would be M8-1.25 or maybe M8-1.0. A U.S. #8 bolt is about half the thickness of a 8mm bolt. Huh?!? What are you on about? It is you who is incorrect not he. He said it was an M6x18. The x is pronounced "by". Put M6x18 in google and click images. You will see M6 bolts in an 18mm length. He chose to identify the bolt by it's diameter and length, just like the rest of the world does most of the time. You are right. I'll change my reply to read "It might be an U.S. size which might be 6-32 or it might be metric in which case it would be M6-1.0. A U.S. #6 bolt is about half the thickness of a 6mm bolt." Happy now? Nope. Please return to the subject, and change your reply to answer the OP's question, which was "Everything seems to be Grade 5. Is that safe enough, or do I really want to (somehow) find Grade 8?" This will require first identifying the most extreme condition that the bolt will experience as long as the rider can hold on and stay upright. The goal is to determine safe enough, and one is not going to be safe after riding at cruising speed into a wall or curb anyway. Hitting a pothole seems reasonable to me, but whatever. Then calculate the tension on the bolt in that situation, and then compare that to specification for grade 8. But what is the value in stating "Grade 5 should certainly be strong enough to hold the bars on." ? So will a rubber band or some scotch tape, as long as one rides slow on smooth road. But there are grades 8 or 9 that are stronger Yes, the OP knows that, and had to to pose the question "Do I need grade 8?" in the first place. You are describing bolts using diameter and pitch. This is incomplete, as it does not specify the length. Further is is irrelevant since the JIS and ISO standards both specify 1.0 as the standard pitch for 6mm bolts. Nope. A thread is described by two things diameter and number of threads per unit. One can easily buy, for example, a 1/4" thread any where from a quarter of an inch long, or so, to three feet, or more. We are not talking about a thread. If you want to talk length then yes. Again the OP was talking about grade; you faulted him for the way he described the bolt, and I am saying that a)he described it in the same way we all do most of the time, which is not flawed, and b)the quality of this method which you say is a flaw also exists in your claim of what is correct. The fact is that a bolt has three identifying characteristics, and all must be expressed in order to avoid being incomplete, and at times, insufficient. Obviously Dorman has already thought this through: https://www.ebay.com/p/?iid=25190411...pp=true&chn=ps A bolt should be long enough that one complete thread will be extend past the nut. but there is not maximum length, un less, or course it hits the other side of the automobile. A triple straw man. It's a bike and there is no nut and length is not the issue. An M6X10 is the metric "functional equivalent" of a 1/4" UNC bolt. It's dimensions and strength are very close. Being a metric bolt it will be neither a Grade 5 nor a Grade 8. - it will be a class 8.8 or 10.9 or 12.9 An 8.8 is the metric "functional equivalent" to a grade 5 Another rephrasing of the question, also posed as an answer. If you wish to be picky then let us be picky. There is no such thing as a M6X10 thread Noone said there was. ...After all a 1 inch 1/4" bolt would have 20 threads on it while your imaginary M6X10 bolt would have only (roughly) 4. They are not imaginary; again, M6x10 is the most common way of describing metric bolts. Unlike when describing traditional US sizes, where standard practice is to state either NC/coarse/USS or NF/fine/SAE, metric bolts have a single standard pitch, and so to not state the pitch is not usually ambiguous, despite not being complete. There are exceptions. The ISO standard pitch for an M8 bolt is 1.25, but the JIS standard is 1.0 (or vice-versa), so when buying M8 bolts for your dirtbike at the hardware store, if it fits in your Yamaha, it is not going to fit in your KTM. Nevertheless, M6x10 is still by far the most common way of referring to metric bolts, and with a standard pitch of 1.0, an M6x10 bolt will have 10 threads. https://www.google.com/search?q=cycl...olt+assortment Metric thread pitch is described totally different than inch size bolts. Inch size is threads per inch. Metric thread is thread pitch - so in inch size bolts, a higher number is a finer thread - in metric a higher number is a coarser thread. A 6X10 metric bolt is 6mm with a thread pitch of 1mm crest to crest (or root to root - however you want to measure it) As far as the "grade" of the bolt - a "grade 8" is NOT always better than a "grade 5" or even, possibly, in some cases, a "grade 2" A grade 2 or grade 5 bolt may bend and stretch - and still hold, where a grade 8 would simply snap. It depends on what kind of load is being carried by the bolt - and how it is torqued. On the same vein, a bolt that is undertorqued CAN fail faster than one that is overtorqued. A properly tensioned bolt is "pre-stretched" just enough that any cyclic load does not stretch the bolt any farther, so the bolt does not fatigue in use. No use arguing with Slocumb though - you'll never get anything through his thick skull. |
Selecting An Appropriate Bolt
On Tue, 18 Apr 2017 16:32:48 -0400, wrote:
On Tue, 18 Apr 2017 18:56:17 +0700, John B Slocomb wrote: On Tue, 18 Apr 2017 00:08:14 -0400, wrote: On Tue, 18 Apr 2017 10:29:32 +0700, John B Slocomb wrote: If you want to talk length then yes. A bolt should be long enough that one complete thread will be extend past the nut. but there is not maximum length, un less, or course it hits the other side of the automobile. This is not true with AN hardware.AN hardware is spec'd by it's diameter and grip length -and there is a stringent spec as to how much thread must/may extend beyond the nut. You NEVER have threads within the "grip" Something must have changed with those AN people after the twenty years I spent fixing their airplanes because the "one thread past the nut" rule was certainly followed then. I've personally seen an Air Force Inspector turn down an installation because the bolt didn't protrude past the nut. (Which is likely why I remember it :-) You didn't read my whole post Slocumb. I was responding to the " but there is not maximum length, un less, or course it hits the other side of the automobile. AN bolts need to be the EXACT length required. No more than 2 washers allowes to adjust the protrusion of the thread through the nut. If it doesn't protrude OR protrudes too much it fails. (at least here in Canada) As I said, for 20 years I fixed my uncles airplanes and I can assure you that AN nuts and bolts weren't quite as exact as you seem to think that they are. Certainly one was supposed to not use more than one washer under the head and the nut but there was no restriction about how much stuck out of the nut, as long as it was at least one thread. You are imagining some perfect place where everything is wonderful when in reality it is 23:30 and a B-52 with two Nukes aboard that either gets off the ground by 24:00 or it misses its rendezvous and the aircraft to be relieved won't have sufficient fuel to get home and another tanker will have to be launched.... |
Selecting An Appropriate Bolt
On Wed, 19 Apr 2017 10:04:13 +0700, John B Slocomb
wrote: On Tue, 18 Apr 2017 16:32:48 -0400, wrote: On Tue, 18 Apr 2017 18:56:17 +0700, John B Slocomb wrote: On Tue, 18 Apr 2017 00:08:14 -0400, wrote: On Tue, 18 Apr 2017 10:29:32 +0700, John B Slocomb wrote: If you want to talk length then yes. A bolt should be long enough that one complete thread will be extend past the nut. but there is not maximum length, un less, or course it hits the other side of the automobile. This is not true with AN hardware.AN hardware is spec'd by it's diameter and grip length -and there is a stringent spec as to how much thread must/may extend beyond the nut. You NEVER have threads within the "grip" Something must have changed with those AN people after the twenty years I spent fixing their airplanes because the "one thread past the nut" rule was certainly followed then. I've personally seen an Air Force Inspector turn down an installation because the bolt didn't protrude past the nut. (Which is likely why I remember it :-) You didn't read my whole post Slocumb. I was responding to the " but there is not maximum length, un less, or course it hits the other side of the automobile. AN bolts need to be the EXACT length required. No more than 2 washers allowes to adjust the protrusion of the thread through the nut. If it doesn't protrude OR protrudes too much it fails. (at least here in Canada) As I said, for 20 years I fixed my uncles airplanes and I can assure you that AN nuts and bolts weren't quite as exact as you seem to think that they are. Certainly one was supposed to not use more than one washer under the head and the nut but there was no restriction about how much stuck out of the nut, as long as it was at least one thread. You are imagining some perfect place where everything is wonderful when in reality it is 23:30 and a B-52 with two Nukes aboard that either gets off the ground by 24:00 or it misses its rendezvous and the aircraft to be relieved won't have sufficient fuel to get home and another tanker will have to be launched.... I'm just going by the rules I need to follow when building my own plane up here. The MDRA looks for "good workmanship" and that means using the right bolts. The bolts come in multiples of 1/8 inch, and that allows getting the length accurate to within 2 washer thicknesses (one on each end) with no problem at all. It DOES require having a good assortment of bolts and washers available though. The Naval Ship's Technical manual states "A good rule to follow is to always use the shortest standard length fastener that gives a minimum one thread protrusion" From the EAA: Certain accepted practices prevail concerning the installation of hardware. A few of these regarding bolt installation follow: •In determining proper bolt length - no more than one thread should be hidden inside the bolt hole. •A typical installation includes a bolt, one washer and a nut. •If the bolt is too long, a maximum of three washers may be used. •If more than three threads are protruding from the nut, the bolt may be too long and could be bottoming out on the shank. In Canada the MDRA will flag a bolt with over 3 threads showing on inspection. |
Selecting An Appropriate Bolt
On Tue, 18 Apr 2017 21:17:55 -0400, wrote:
On Tue, 18 Apr 2017 14:15:09 -0700 (PDT), Doug Landau wrote: On Monday, April 17, 2017 at 8:29:53 PM UTC-7, John B Slocomb wrote: On Mon, 17 Apr 2017 17:51:39 -0400, wrote: On Mon, 17 Apr 2017 13:52:56 -0700 (PDT), Doug Landau wrote: On Friday, April 14, 2017 at 4:15:34 AM UTC-7, John B Slocomb wrote: On Thu, 13 Apr 2017 20:07:48 -0700, Art Shapiro wrote: I had a bit of an adventure when one of the two handlebar-fixing bolts on my Deda Murex quilled stem decided to snap with a rather impressive cracking noise. I somehow didn't crash and happened to be only about seven miles from home. I got slowly home holding the stem with one hand and one of the brake levers on the dangling handlebars with the other hand. (This is not recommended to the reader.) I see that the bolt is a M6x18 tapered cone head Allen cap screw with pressed-on washer. The stem is two months shy of 15 years old, but I don't want to have this happen again. Looking on eBay, I see quite a few appropriate bolts, but I'm not sure what is optimal. Can anyone help? Everything seems to be Grade 5. Is that safe enough, or do I really want to (somehow) find Grade 8? Many are titanium. Is that a better choice than the more-common steel? Or should I look for stainless steel? I am always happy to save a few grams, but not if that's a significant risk. Advice welcome! Art Grade 5 bolts should certainly be strong enough to hold the handle bars on. But there are grades 8 or 9 that are stronger. What makes you say this? Do you have some #s to back this statement up, or is it just your wild guess? Have you calculated the load on this part when when a rider of a given weight hits a pothole at a given speed, or ??? And more importantly, why skimp here? As an aside your description is incorrect. It might be an U.S. size which might be 8-32 or it might be metric in which case it would be M8-1.25 or maybe M8-1.0. A U.S. #8 bolt is about half the thickness of a 8mm bolt. Huh?!? What are you on about? It is you who is incorrect not he. He said it was an M6x18. The x is pronounced "by". Put M6x18 in google and click images. You will see M6 bolts in an 18mm length. He chose to identify the bolt by it's diameter and length, just like the rest of the world does most of the time. You are right. I'll change my reply to read "It might be an U.S. size which might be 6-32 or it might be metric in which case it would be M6-1.0. A U.S. #6 bolt is about half the thickness of a 6mm bolt." Happy now? Nope. Please return to the subject, and change your reply to answer the OP's question, which was "Everything seems to be Grade 5. Is that safe enough, or do I really want to (somehow) find Grade 8?" This will require first identifying the most extreme condition that the bolt will experience as long as the rider can hold on and stay upright. The goal is to determine safe enough, and one is not going to be safe after riding at cruising speed into a wall or curb anyway. Hitting a pothole seems reasonable to me, but whatever. Then calculate the tension on the bolt in that situation, and then compare that to specification for grade 8. But what is the value in stating "Grade 5 should certainly be strong enough to hold the bars on." ? So will a rubber band or some scotch tape, as long as one rides slow on smooth road. But there are grades 8 or 9 that are stronger Yes, the OP knows that, and had to to pose the question "Do I need grade 8?" in the first place. You are describing bolts using diameter and pitch. This is incomplete, as it does not specify the length. Further is is irrelevant since the JIS and ISO standards both specify 1.0 as the standard pitch for 6mm bolts. Nope. A thread is described by two things diameter and number of threads per unit. One can easily buy, for example, a 1/4" thread any where from a quarter of an inch long, or so, to three feet, or more. We are not talking about a thread. If you want to talk length then yes. Again the OP was talking about grade; you faulted him for the way he described the bolt, and I am saying that a)he described it in the same way we all do most of the time, which is not flawed, and b)the quality of this method which you say is a flaw also exists in your claim of what is correct. The fact is that a bolt has three identifying characteristics, and all must be expressed in order to avoid being incomplete, and at times, insufficient. Obviously Dorman has already thought this through: https://www.ebay.com/p/?iid=25190411...pp=true&chn=ps A bolt should be long enough that one complete thread will be extend past the nut. but there is not maximum length, un less, or course it hits the other side of the automobile. A triple straw man. It's a bike and there is no nut and length is not the issue. An M6X10 is the metric "functional equivalent" of a 1/4" UNC bolt. It's dimensions and strength are very close. Being a metric bolt it will be neither a Grade 5 nor a Grade 8. - it will be a class 8.8 or 10.9 or 12.9 An 8.8 is the metric "functional equivalent" to a grade 5 Another rephrasing of the question, also posed as an answer. If you wish to be picky then let us be picky. There is no such thing as a M6X10 thread Noone said there was. ...After all a 1 inch 1/4" bolt would have 20 threads on it while your imaginary M6X10 bolt would have only (roughly) 4. They are not imaginary; again, M6x10 is the most common way of describing metric bolts. Unlike when describing traditional US sizes, where standard practice is to state either NC/coarse/USS or NF/fine/SAE, metric bolts have a single standard pitch, and so to not state the pitch is not usually ambiguous, despite not being complete. There are exceptions. The ISO standard pitch for an M8 bolt is 1.25, but the JIS standard is 1.0 (or vice-versa), so when buying M8 bolts for your dirtbike at the hardware store, if it fits in your Yamaha, it is not going to fit in your KTM. Nevertheless, M6x10 is still by far the most common way of referring to metric bolts, and with a standard pitch of 1.0, an M6x10 bolt will have 10 threads. https://www.google.com/search?q=cycl...olt+assortment Metric thread pitch is described totally different than inch size bolts. Inch size is threads per inch. Metric thread is thread pitch - so in inch size bolts, a higher number is a finer thread - in metric a higher number is a coarser thread. A 6X10 metric bolt is 6mm with a thread pitch of 1mm crest to crest (or root to root - however you want to measure it) Who cares, along as the people involved know what you are talking about? Ant metering system is just that, a system which works for those that use it. The old method of measuring gear ratios on a bicycle was to use "gear inches" which described the diameter of a wheel that would move the distance in one revolution. Rather archaic today but made perfect sense to those that used it. As far as the "grade" of the bolt - a "grade 8" is NOT always better than a "grade 5" or even, possibly, in some cases, a "grade 2" A grade 2 or grade 5 bolt may bend and stretch - and still hold, where a grade 8 would simply snap. It depends on what kind of load is being carried by the bolt - and how it is torqued. On the same vein, a bolt that is undertorqued CAN fail faster than one that is overtorqued. A properly tensioned bolt is "pre-stretched" just enough that any cyclic load does not stretch the bolt any farther, so the bolt does not fatigue in use. An exciting theory and technically correct. although I would comment that I've yet to see an under torque bolt break. No use arguing with Slocumb though - you'll never get anything through his thick skull. I served a 4 year apprenticeship and had my papers as a journeyman machinist in 1950. Was a licensed A&E mechanic two years later (note in those days it was Aircraft and Engine) joined the Air Force to avoid being drafted and was in aircraft maintenance for 20 years. When I retired I went to work in the mining business where that called me a "Master Mechanic" for some reason. So yes, I reckon I do know a bit about fasteners, having dealt with them for 70 years or so. Certainly not everything but probably enough to tell the difference between a metric and inch thread. |
Selecting An Appropriate Bolt
On 4/18/2017 11:45 PM, wrote:
On Wed, 19 Apr 2017 10:04:13 +0700, John B Slocomb wrote: On Tue, 18 Apr 2017 16:32:48 -0400, wrote: On Tue, 18 Apr 2017 18:56:17 +0700, John B Slocomb wrote: On Tue, 18 Apr 2017 00:08:14 -0400, wrote: On Tue, 18 Apr 2017 10:29:32 +0700, John B Slocomb wrote: If you want to talk length then yes. A bolt should be long enough that one complete thread will be extend past the nut. but there is not maximum length, un less, or course it hits the other side of the automobile. This is not true with AN hardware.AN hardware is spec'd by it's diameter and grip length -and there is a stringent spec as to how much thread must/may extend beyond the nut. You NEVER have threads within the "grip" Something must have changed with those AN people after the twenty years I spent fixing their airplanes because the "one thread past the nut" rule was certainly followed then. I've personally seen an Air Force Inspector turn down an installation because the bolt didn't protrude past the nut. (Which is likely why I remember it :-) You didn't read my whole post Slocumb. I was responding to the " but there is not maximum length, un less, or course it hits the other side of the automobile. AN bolts need to be the EXACT length required. No more than 2 washers allowes to adjust the protrusion of the thread through the nut. If it doesn't protrude OR protrudes too much it fails. (at least here in Canada) As I said, for 20 years I fixed my uncles airplanes and I can assure you that AN nuts and bolts weren't quite as exact as you seem to think that they are. Certainly one was supposed to not use more than one washer under the head and the nut but there was no restriction about how much stuck out of the nut, as long as it was at least one thread. You are imagining some perfect place where everything is wonderful when in reality it is 23:30 and a B-52 with two Nukes aboard that either gets off the ground by 24:00 or it misses its rendezvous and the aircraft to be relieved won't have sufficient fuel to get home and another tanker will have to be launched.... I'm just going by the rules I need to follow when building my own plane up here. The MDRA looks for "good workmanship" and that means using the right bolts. The bolts come in multiples of 1/8 inch, and that allows getting the length accurate to within 2 washer thicknesses (one on each end) with no problem at all. It DOES require having a good assortment of bolts and washers available though. The Naval Ship's Technical manual states "A good rule to follow is to always use the shortest standard length fastener that gives a minimum one thread protrusion" From the EAA: Certain accepted practices prevail concerning the installation of hardware. A few of these regarding bolt installation follow: •In determining proper bolt length - no more than one thread should be hidden inside the bolt hole. •A typical installation includes a bolt, one washer and a nut. •If the bolt is too long, a maximum of three washers may be used. •If more than three threads are protruding from the nut, the bolt may be too long and could be bottoming out on the shank. In Canada the MDRA will flag a bolt with over 3 threads showing on inspection. I don't get it. What's the downside of having an extra thread or two beyond the nut? -- - Frank Krygowski |
Selecting An Appropriate Bolt
On Monday, April 17, 2017 at 1:52:58 PM UTC-7, Doug Landau wrote:
The stem is two months shy of 15 years old, but I don't want to have this happen again. Get a new stem. This one is a flawed design. There is built-in problem with the shape of the part, and that is a lack of remaining metal around the bolt hole. The stem has been made bigger around the front bolt hole to overcome this, but it still has the 2-bolt-1-failure problem. The traditional shape does not make this concession to ease-of-handlebar-change, and carefully places the single bolt in the rear where there is plenty of metal surrounding the threads. The traditional design is both less likely to experience a bolt failure, and - in the wild guess dept., be more likely to hold on to the bars and remain usable in the event that one does. Deda Murex 2-bolt: https://www.google.com/search?q=deda...f3AGoQ_AUIBygC 3ttt traditional: https://www.google.com/search?q=3ttt...w=1306&bih=724 Doug - a stem should NOT be designed in such a manner that it is being held from failing by a bolt. These should be only there to put the parts together and the forces should be held in check by the design of the stem. Yes, most stems are not so designed but most stems come from China where they don't have to worry about lawsuits from Americans. A stem should have TWO bolts to tighten it to a steerer only to tighten it from rotating. And two bolts so that one breaking does not disable this capacity. Why on Earth would anyone question that? The handlebar mount likewise should have four bolts on it and the mount should be angled and a step placed in it so that the stem itself is carrying the load of a handlebar and not the bolts that are only there to assemble it. Old fashioned threaded-head style stems were vastly overbuilt precisely because they were afraid of aluminum. We have more experience and better alloys today and don't have one single angle of stem to pretend racer with. And those old stems had way oversized stem bolts and still failed because of bolts being given sidewise forces in most of them other than Cinelli who were real engineers. |
Selecting An Appropriate Bolt
On Monday, April 17, 2017 at 8:29:53 PM UTC-7, John B Slocomb wrote:
On Mon, 17 Apr 2017 16:19:15 -0700 (PDT), Doug Landau wrote: On Friday, April 14, 2017 at 11:11:18 AM UTC-7, Frank Krygowski wrote: On 4/14/2017 12:33 PM, jbeattie wrote: On Friday, April 14, 2017 at 7:27:06 AM UTC-7, AMuzi wrote: On 4/14/2017 9:14 AM, Art Shapiro wrote: On 4/14/2017 5:35 AM, AMuzi wrote: Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. How does one get these "readily available" Grade 8 guys? Deda doesn't seem to have much of a web presence outside of Italy. Is this a generic item stocked by a good LBS? Any metric fastener supplier if not your local hardware store. https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web My neighborhood hardware store has them: http://aboysupply.com/wp-content/upl...1024x415_c.png They have a crazy selection of fasteners. By the way, what's the deal with thread pitch? I always worry I'm getting the wrong pitch, but I guess that the whole "standard/fine/extra fine" thread pitch only kicks in with fasteners over 8mm(?). Otherwise, it's a pre-set. Right? No. It's just the charts that only kick in at 8. They are clearly both a)written by someone who doesn't actually know, themselves, and b)plagarising heavily from each other, and repeating the other's mistakes. There are metric fine pitch threads https://mdmetric.com/tech/thddat3.htm like 5mm-0.5 instead of 5mm-0.8 That chart is ****ed up. It says fine but lists more than one thread pitch in the first column, and inconsistently shows extra- and super-fine pitches instead. The commonly found standard M5 bolt is indeed 0.8 pitch, but the commonly found fine pitch M5 is 0.7. 0.5 must be extra-fine or super-fine. Which is why when you buy a tap and dies set it comes with 5-.8 and 5-.7 but not 5-.5. I think but am not 100% sure that M6 fine is 0.8 not 0.75. http://www.sears.com/craftsman-39-pc...g&gclsrc=aw.ds but I've hardly ever come across them in real life. No? Are you sure - you've never chased munged up pedal threads? Doing so sends you down to the hardware store for an M10-1.0 tap, because your tap and dies set comes with a 10-1.5 (standard) and 10-1.25 (fine). There is at least one other place where there is a fine thread, an 8, I think, and I think it's the brake pivot bolt, but am not sure I'm remembering correctly. What's the thread pitch of derailer hangers? The "fine thread - course thread" discussion if essentially a very simplistic categorizing of fasteners. The U.S. Unified thread system provides a sort of rationalization for a UNC/UNF series but that didn't and doesn't prevent fasteners being made in a large number of thread pitches. In U.S. sizes we have, for example, the 1/4"x20tpi (National Course), the 1/4 x 24 (NS), the 1/4 x 28 (NF), the 1/4 x 32 (NEF) and the 1/4 x 40 (NS). From memory the difference between American fine and course is the depth of the thread. Course threads cut much deeper into the mating piece to achieve the same amount of metal to metal contact as fine threads. |
Selecting An Appropriate Bolt
On 4/19/2017 11:12 AM, wrote:
On Monday, April 17, 2017 at 8:29:53 PM UTC-7, John B Slocomb wrote: On Mon, 17 Apr 2017 16:19:15 -0700 (PDT), Doug Landau wrote: On Friday, April 14, 2017 at 11:11:18 AM UTC-7, Frank Krygowski wrote: On 4/14/2017 12:33 PM, jbeattie wrote: On Friday, April 14, 2017 at 7:27:06 AM UTC-7, AMuzi wrote: On 4/14/2017 9:14 AM, Art Shapiro wrote: On 4/14/2017 5:35 AM, AMuzi wrote: Original handlebar clamp bolts are Grade 8; readily available and cheap. Grade 5 may be strong enough but for pennies difference I suggest an 8. How does one get these "readily available" Grade 8 guys? Deda doesn't seem to have much of a web presence outside of Italy. Is this a generic item stocked by a good LBS? Any metric fastener supplier if not your local hardware store. https://duckduckgo.com/?q=DIN+912+grade+8&t=ha&ia=web My neighborhood hardware store has them: http://aboysupply.com/wp-content/upl...1024x415_c.png They have a crazy selection of fasteners. By the way, what's the deal with thread pitch? I always worry I'm getting the wrong pitch, but I guess that the whole "standard/fine/extra fine" thread pitch only kicks in with fasteners over 8mm(?). Otherwise, it's a pre-set. Right? No. It's just the charts that only kick in at 8. They are clearly both a)written by someone who doesn't actually know, themselves, and b)plagarising heavily from each other, and repeating the other's mistakes. There are metric fine pitch threads https://mdmetric.com/tech/thddat3.htm like 5mm-0.5 instead of 5mm-0.8 That chart is ****ed up. It says fine but lists more than one thread pitch in the first column, and inconsistently shows extra- and super-fine pitches instead. The commonly found standard M5 bolt is indeed 0.8 pitch, but the commonly found fine pitch M5 is 0.7. 0.5 must be extra-fine or super-fine. Which is why when you buy a tap and dies set it comes with 5-.8 and 5-.7 but not 5-.5. I think but am not 100% sure that M6 fine is 0.8 not 0.75. http://www.sears.com/craftsman-39-pc...g&gclsrc=aw.ds but I've hardly ever come across them in real life. No? Are you sure - you've never chased munged up pedal threads? Doing so sends you down to the hardware store for an M10-1.0 tap, because your tap and dies set comes with a 10-1.5 (standard) and 10-1.25 (fine). There is at least one other place where there is a fine thread, an 8, I think, and I think it's the brake pivot bolt, but am not sure I'm remembering correctly. What's the thread pitch of derailer hangers? The "fine thread - course thread" discussion if essentially a very simplistic categorizing of fasteners. The U.S. Unified thread system provides a sort of rationalization for a UNC/UNF series but that didn't and doesn't prevent fasteners being made in a large number of thread pitches. In U.S. sizes we have, for example, the 1/4"x20tpi (National Course), the 1/4 x 24 (NS), the 1/4 x 28 (NF), the 1/4 x 32 (NEF) and the 1/4 x 40 (NS). From memory the difference between American fine and course is the depth of the thread. Course threads cut much deeper into the mating piece to achieve the same amount of metal to metal contact as fine threads. Not just ANC/ANF. Greater depth at coarser pitches is inherent to a triangular or sine thread form: http://www.oldengine.org/members/diesel/Tables/form.htm It's not geometrically inherent to an Acme or similar thread although those are noted for hefty-load depths. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
Selecting An Appropriate Bolt
On Wed, 19 Apr 2017 18:43:02 +0700, John B Slocomb
wrote: Metric thread pitch is described totally different than inch size bolts. Inch size is threads per inch. Metric thread is thread pitch - so in inch size bolts, a higher number is a finer thread - in metric a higher number is a coarser thread. A 6X10 metric bolt is 6mm with a thread pitch of 1mm crest to crest (or root to root - however you want to measure it) Who cares, along as the people involved know what you are talking about? Ant metering system is just that, a system which works for those that use it. The old method of measuring gear ratios on a bicycle was to use "gear inches" which described the diameter of a wheel that would move the distance in one revolution. Rather archaic today but made perfect sense to those that used it. As far as the "grade" of the bolt - a "grade 8" is NOT always better than a "grade 5" or even, possibly, in some cases, a "grade 2" A grade 2 or grade 5 bolt may bend and stretch - and still hold, where a grade 8 would simply snap. It depends on what kind of load is being carried by the bolt - and how it is torqued. On the same vein, a bolt that is undertorqued CAN fail faster than one that is overtorqued. A properly tensioned bolt is "pre-stretched" just enough that any cyclic load does not stretch the bolt any farther, so the bolt does not fatigue in use. An exciting theory and technically correct. although I would comment that I've yet to see an under torque bolt break. It's far from "theory" - I've seen numerous head bolts and manifold bolts fail that were attributed to being under-torqued on vehicles that were not properly PDId, and quite a few bolts that failed in shear because they were not properly tightened, and/or the holes were not properly de-burred, allowing the bolt to loose tension. No use arguing with Slocumb though - you'll never get anything through his thick skull. I served a 4 year apprenticeship and had my papers as a journeyman machinist in 1950. Was a licensed A&E mechanic two years later (note in those days it was Aircraft and Engine) joined the Air Force to avoid being drafted and was in aircraft maintenance for 20 years. When I retired I went to work in the mining business where that called me a "Master Mechanic" for some reason. So yes, I reckon I do know a bit about fasteners, having dealt with them for 70 years or so. Certainly not everything but probably enough to tell the difference between a metric and inch thread. Some are pretty difficult to differentiate between without having the wrong bolt for the hole, or the wrong nut for the bolt/stud. |
Selecting An Appropriate Bolt
On Wed, 19 Apr 2017 11:47:24 -0400, Frank Krygowski
wrote: On 4/18/2017 11:45 PM, wrote: On Wed, 19 Apr 2017 10:04:13 +0700, John B Slocomb wrote: On Tue, 18 Apr 2017 16:32:48 -0400, wrote: On Tue, 18 Apr 2017 18:56:17 +0700, John B Slocomb wrote: On Tue, 18 Apr 2017 00:08:14 -0400, wrote: On Tue, 18 Apr 2017 10:29:32 +0700, John B Slocomb wrote: If you want to talk length then yes. A bolt should be long enough that one complete thread will be extend past the nut. but there is not maximum length, un less, or course it hits the other side of the automobile. This is not true with AN hardware.AN hardware is spec'd by it's diameter and grip length -and there is a stringent spec as to how much thread must/may extend beyond the nut. You NEVER have threads within the "grip" Something must have changed with those AN people after the twenty years I spent fixing their airplanes because the "one thread past the nut" rule was certainly followed then. I've personally seen an Air Force Inspector turn down an installation because the bolt didn't protrude past the nut. (Which is likely why I remember it :-) You didn't read my whole post Slocumb. I was responding to the " but there is not maximum length, un less, or course it hits the other side of the automobile. AN bolts need to be the EXACT length required. No more than 2 washers allowes to adjust the protrusion of the thread through the nut. If it doesn't protrude OR protrudes too much it fails. (at least here in Canada) As I said, for 20 years I fixed my uncles airplanes and I can assure you that AN nuts and bolts weren't quite as exact as you seem to think that they are. Certainly one was supposed to not use more than one washer under the head and the nut but there was no restriction about how much stuck out of the nut, as long as it was at least one thread. You are imagining some perfect place where everything is wonderful when in reality it is 23:30 and a B-52 with two Nukes aboard that either gets off the ground by 24:00 or it misses its rendezvous and the aircraft to be relieved won't have sufficient fuel to get home and another tanker will have to be launched.... I'm just going by the rules I need to follow when building my own plane up here. The MDRA looks for "good workmanship" and that means using the right bolts. The bolts come in multiples of 1/8 inch, and that allows getting the length accurate to within 2 washer thicknesses (one on each end) with no problem at all. It DOES require having a good assortment of bolts and washers available though. The Naval Ship's Technical manual states "A good rule to follow is to always use the shortest standard length fastener that gives a minimum one thread protrusion" From the EAA: Certain accepted practices prevail concerning the installation of hardware. A few of these regarding bolt installation follow: •In determining proper bolt length - no more than one thread should be hidden inside the bolt hole. •A typical installation includes a bolt, one washer and a nut. •If the bolt is too long, a maximum of three washers may be used. •If more than three threads are protruding from the nut, the bolt may be too long and could be bottoming out on the shank. In Canada the MDRA will flag a bolt with over 3 threads showing on inspection. I don't get it. What's the downside of having an extra thread or two beyond the nut? With AN hardware there is only a small amount of thread - so if there is more than 3 threads showing the chances are VERY good that the nut is bottomed on the thread - therefore to be safe, the next shorter bolt (1/8" shorter)needs to be installed. Airplane guys are pretty anal - and for good reason. |
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