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#11
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drill/tap in frames
On Sun, 08 Jul 2018 01:08:28 +0200, Emanuel Berg
wrote: Jeff Liebermann wrote: The tubing is probably too thin for threading the hole. You need at least 3 full threads wall thickness tubing to keep the mounting screw from stripping the threads out of the hole. For an M5x0.8, that's 0.8 mm per thread. So, the minimum tubing wall thickness would be 2.4mm. However, since the tubing on your bicycle is probably around 0.5mm wall thickness, the tubing wall will never be thick enough to support threading. To get more threads to grip is one reason why builders use braze on bosses for mount points. I keep hearing this, Then, it doesn't hurt to repeat it a few more times until you become a believer. Please repeat a few hundred times: "Thin wall tubing should not be threaded" but it isn't the case for my bikes which have chainguards. These have three stays, and of those, two are mounted on the bike frame with M5 screws. Threaded hole, no nut on the other side! How thick is the tubing at the 3 stays? Are you sure that there isn't a Rivnut, PEM nut, or other threaded insert in the stays? Then the chainguard is mounted on the stays, likewise with M5s, threaded holes (only here sometimes there are nuts as well). How do you install a nut when the ends of the stays are all welded shut? There's no sane way to install a nut inside the stays. Hopefully, your machine does not have an M5 fastener going though both sides of the stays, and secured by a Nyloc nut? Overtighten and you'll crush the stays. The stays are about 1mm. How thick the frame tube wall is I don't know, but I can take a discarded frame and cut it with an angle grinder to find out, God willing. The stays are likely to be double butted, with different thicknesses at the ends, compared to the middle of the tube. If you don't mind drilling a tiny hole in your scrap bicycle frame, you can easily measure the thickness. 1. Drill a very small hole in one side of the tube. If you plan to ride this bike again, drill on side of the tube that will drain water. 2. Make a straight pin that is long enough to go through the hole and hit the opposite side while having a little stick out of the hole. 3. Measure the length of the pin accurately with calipers. Flatten the ends if necessary. 4. Using the same caliper as above, measure between the projecting pin end, and the far end of the tubing. 5. Subtract the length of the pin from the above measurement and you have the wall thickness. 6. Plug the drill hole so water doesn't enter. This ain't to say that rivnuts ain't a good idea, of course. Make sure you use steel Rivnuts on a steel frame. Never mind. It's a dumb idea. An M5 Rivnut is going to require a 7.0 mm (+0.1/-0 mm) hole. That's going to seriously weaken the stays. If you notch the hole to prevent rotation of the Rivnut, you also get a stress riser. Don't do it. BTW, do you by them online? I don't think they are in our HW stores... (which is common with the stuff you guys mention: durometer, soft jaw pliers, etc.) Actually, I steal them from former employers and companies where I consult. Same with other consumables, such as pop rivets, office supplies, electronic parts, etc. I'm still using parts that I stole perhaps 30 years ago. I bought my durometer on eBay. I've never seen one in a retail automotive parts sto https://www.ebay.com/itm/322919230951 My soft jaw pliers came with an ITT Cannon circular connector kit. I have three with different tubing diameters. https://www.google.com/search?q=cannon+connector+pliers&tbm=isch However, they're quite expensive from Cannon, so I would get something cheaper: https://www.google.com/search?q=soft+jaw+pliers&tbm=isch Someone sells plastic covers that slide over the jaws to convert channel locks into soft jaw pliers. Avoid. They don't work very well. 147 hardware stores in Stockholm: https://www.yelp.com/search?cflt=hardware&find_loc=Stockholm -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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#12
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drill/tap in frames
On 7/7/2018 4:08 PM, Emanuel Berg wrote:
Jeff Liebermann wrote: The tubing is probably too thin for threading the hole. You need at least 3 full threads wall thickness tubing to keep the mounting screw from stripping the threads out of the hole. For an M5x0.8, that's 0.8 mm per thread. So, the minimum tubing wall thickness would be 2.4mm. However, since the tubing on your bicycle is probably around 0.5mm wall thickness, the tubing wall will never be thick enough to support threading. To get more threads to grip is one reason why builders use braze on bosses for mount points. I keep hearing this, but it isn't the case for my bikes which have chainguards. These have three stays, and of those, two are mounted on the bike frame with M5 screws. Threaded hole, no nut on the other side! Then the chainguard is mounted on the stays, likewise with M5s, threaded holes (only here sometimes there are nuts as well). The stays are about 1mm. How thick the frame tube wall is I don't know, but I can take a discarded frame and cut it with an angle grinder to find out, God willing. This ain't to say that rivnuts ain't a good idea, of course. BTW, do you by them online? I don't think they are in our HW stores... (which is common with the stuff you guys mention: durometer, soft jaw pliers, etc.) In my area you can by them over the counter at a fastener company (http://olander.com/). Probably few, if any, hardware stores carry them. |
#13
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drill/tap in frames
sms wrote:
In my area you can by them over the counter at a fastener company (http://olander.com/). Probably few, if any, hardware stores carry them. Ain't it the truth! I always said the hardware store were overrated, save for the hot chics in their early and mid 20s that works there, which BTW is a capitalist trick so that there won't be a prestige contest who supposedly knows more, and the relaxed and content customers will buy even more. -- underground experts united http://user.it.uu.se/~embe8573 |
#14
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drill/tap in frames
On Sun, 8 Jul 2018 09:10:49 -0700, sms
wrote: In my area you can by them over the counter at a fastener company (http://olander.com/). Probably few, if any, hardware stores carry them. Fastenal also carries Rivnuts: https://www.fastenal.com/product/fasteners/rivets/rivet-nuts/602457?categoryId=602457&level=3 Nearest stores are probably in Mtn View and Santa Clara. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#15
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drill/tap in frames
On 7/7/2018 6:00 PM, Emanuel Berg wrote:
Doug Cimperman wrote: 1) A drill press w/vise will work far better than a hand drill. If you use a hand drill in thicker (1mm) metal, the bits will go dull really fast and tend to break as they come out the back side of the hole. Drill bits, is there a reason to use those instead of just drills (round)? I am not sure what you mean by drill bits not being round? Drill bits with hex or triangle shanks tend to break if they snag in metal. It is better to use a smooth-shank drill bit since if it snags, it will just spin in the chuck instead of breaking. As I understand it, "drill" is the term for the entire tool--either hand-held, or bench- or floor-standing. A "drill bit" is the part that actually makes the hole: https://www.mcmaster.com/#30565a274/=1dmner9 (5.2mm, $2.89 each) I must admit that I kinda prefer buying drills elsewhere... McMaster is fast & easy but they usually do not say what brand you are getting. For HSS drills and taps I usually buy the Hertel brand at MSC: https://www.mscdirect.com/product/details/01076504 (5.2mm, $2.91) |
#16
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drill/tap in frames
On 7/7/2018 7:27 AM, Emanuel Berg wrote:
Are there any secrets to drilling holes in steel bike frames? I have a couple of discarded ones I can test on but I thought I'd ask anyway. Do you use normal power hand tools like a drill-screwdriver and/or a drill press (if possible with the desired bolt position)? Do the normal rules apply, e.g. to get a threaded hole for an M6, you first drill with a 5.0mm drill? And you can use chainsaw oil, right? As Jobst Brandt stated: "I don't know many riders who believe that drilling a hole in a frame tube is a reasonable concept." |
#17
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drill/tap in frames
On Sun, 8 Jul 2018 09:10:49 -0700, sms
wrote: On 7/7/2018 4:08 PM, Emanuel Berg wrote: Jeff Liebermann wrote: The tubing is probably too thin for threading the hole. You need at least 3 full threads wall thickness tubing to keep the mounting screw from stripping the threads out of the hole. For an M5x0.8, that's 0.8 mm per thread. So, the minimum tubing wall thickness would be 2.4mm. However, since the tubing on your bicycle is probably around 0.5mm wall thickness, the tubing wall will never be thick enough to support threading. To get more threads to grip is one reason why builders use braze on bosses for mount points. It depends a lot on what the tube set is design for. A top tier road bike (steel) will likely have tubes in the 0.5 - 1 mm thickness range. Spirit - a top of the line triple butted frame set with oversized tubes will be (top tube) 31mm O.D., and wall thickness of 0.5 - 0.38 - 0.5mm. Steel frames traditionally use a small threaded boss soldered on where the screw is required and other materials often use a "Rivnut", which before anyone starts to disparage them should understand that they were originally designed to provide blind holes in aircraft structure and used literally by the millions. Successfully :-) I keep hearing this, but it isn't the case for my bikes which have chainguards. These have three stays, and of those, two are mounted on the bike frame with M5 screws. Threaded hole, no nut on the other side! Then the chainguard is mounted on the stays, likewise with M5s, threaded holes (only here sometimes there are nuts as well). The stays are about 1mm. How thick the frame tube wall is I don't know, but I can take a discarded frame and cut it with an angle grinder to find out, God willing. The normal engaged thread length depends on the diameter of the bolt and the "standard" (strength) For example, an M5 screw (grade 6h/6g) will have a minimum stressed (threaded)area some 4.0103 mm long. This is usually felt to be a sufficient thread engagement to provide some 100% of shank strength. There are innumerable tables available giving the required data. This ain't to say that rivnuts ain't a good idea, of course. BTW, do you by them online? I don't think they are in our HW stores... (which is common with the stuff you guys mention: durometer, soft jaw pliers, etc.) In my area you can by them over the counter at a fastener company (http://olander.com/). Probably few, if any, hardware stores carry them. -- Cheers, John B. |
#18
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drill/tap in frames
On Sat, 07 Jul 2018 17:54:40 +0200, Emanuel Berg wrote:
AMuzi wrote: Subtract pitch from major diameter, e.g., tap drill for an m5x0.8 is 4.2mm Well, then you still have to look up the pitch, which is in the same table as the drill diameter, all of which is faster than the thread gauge... Yes use chainsaw oil on your chainsaw. Won't that trigger a dangerous chain reaction? I saw what you did there. -- davethedave |
#19
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drill/tap in frames
sms wrote:
:On 7/7/2018 7:27 AM, Emanuel Berg wrote: : Are there any secrets to drilling holes in : steel bike frames? I have a couple of discarded : ones I can test on but I thought I'd : ask anyway. : : Do you use normal power hand tools like : a drill-screwdriver and/or a drill press (if : possible with the desired bolt position)? : : Do the normal rules apply, e.g. to get : a threaded hole for an M6, you first drill with : a 5.0mm drill? : : And you can use chainsaw oil, right? :As Jobst Brandt stated: "I don't know many riders who believe that :drilling a hole in a frame tube is a reasonable concept." Who cares what riders think, what do the egineers do? -- sig 47 |
#20
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drill/tap in frames
On Mon, 9 Jul 2018 16:21:43 +0000 (UTC), David Scheidt
wrote: sms wrote: :On 7/7/2018 7:27 AM, Emanuel Berg wrote: : Are there any secrets to drilling holes in : steel bike frames? I have a couple of discarded : ones I can test on but I thought I'd : ask anyway. : : Do you use normal power hand tools like : a drill-screwdriver and/or a drill press (if : possible with the desired bolt position)? : : Do the normal rules apply, e.g. to get : a threaded hole for an M6, you first drill with : a 5.0mm drill? : : And you can use chainsaw oil, right? :As Jobst Brandt stated: "I don't know many riders who believe that :drilling a hole in a frame tube is a reasonable concept." Who cares what riders think, what do the egineers do? Jobst Brandt was a mechanical engineer. https://en.wikipedia.org/wiki/Jobst_Brandt What's an egineer? -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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