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#51
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drill/tap in frames
Joy Beeson wrote:
I put it there with cable ties ("wires") but there was an annoying sound while riding the bike. You need a hose clamp. Wrap the tube with handlebar tape to protect the paint. Also, clamp on tape has a much higher co-efficient of friction than clamp on hard surface. I attached two bottle cages this way late in the twentieth century, and haven't thought about them since. Good idea, I'll try that next. The hose clamp is an underrated commodity when it comes to bikes. -- underground experts united http://user.it.uu.se/~embe8573 |
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#52
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drill/tap in frames
On 7/11/2018 11:42 AM, Jeff Liebermann wrote:
On Tue, 10 Jul 2018 20:41:08 -0700, John B. Slocomb wrote: On Sat, 07 Jul 2018 12:33:38 -0700, Jeff Liebermann wrote: On Sat, 7 Jul 2018 11:06:52 -0400, Frank Krygowski wrote: This group has debated Rivnuts extensively. One poster claims nobody should install a Rivnut unless he has access to a complete machine shop. Others with more experience have said that the installation is easy for anyone with normal mechanical skills. That would be SMS (Steven Scharf) on one of his web pages: http://nordicgroup.us/cageboss/ Since I've made a mess with all the available technologies, Rivnuts (steel and aluminum), brazing (steel), TIG (aluminum), and epoxy glue (plastic boss on aluminum), I'll remain neutral on the matter. Hint: Use steel Rivnuts on steel frames, aluminum Rivnuts on aluminum frame, and plastic straps or clamps on CF (carbon fiber). One can only suppose that those "dumb asses: that manufacture rivnuts deliberately make their product in a number of materials :-) I'm not sure about the deliberate part, but yes, one can buy them in steel or aluminum. I couldn't find any plastic or carbon fiber rivnuts. And, it might be added that not knowing what you are doing is not limited to bicycle maintenence :-) True. If those expounding on bicycle technology by various electronic means really knew what they were doing, they would be riding instead of pounding on the keyboard. If you really want to know how things work, find someone that is actually doing the work and interrogate them for the information you need and don't bother reading books, manufacturers literature, magazines, forums, and newsgroups. The only downside is that those who really know, tend to be inarticulate and have difficulties explaining complex concepts, like which way to tighten a right handed bolt. However, persistence, intimidation, and perhaps bribery will eventually produce the required answer from a real expert. As I mentioned, I have successfully trashed most everything I've tried to do with Rivnuts on bicycles, and therefore have no opinion on the matter. However, it might be interesting to try a simple test. I could probably finance the test by taking bets on the outcome. Take two identical lengths of steel bicycle tubing. Install a Rivnut in only one tube at midpoint. Clamp one end in a pipe vise. Pull on the other end with a Come-Along perpendicular to the tubing. Measure the force with a load cell. Draw a graph to show when the tubing went plastic and eventually buckled. Compare results between the tubing with and without the Rivnut. That should settle the debate whether Rivnuts are detrimental to frame and stay strength. I think the question isn't so much 'has the tube's ultimate strength been diminished?' but rather 'is it yet strong enough for expected application?'. In theory and in absolute yes the tube is less strong. In practice, from Santana ExoGrid tandems to Bianchi thinwall tempered aluminum models, to their carbon bikes, rivnuts are not a failure point. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
#53
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drill/tap in frames
On 7/11/2018 2:42 PM, Emanuel Berg wrote:
Joy Beeson wrote: I put it there with cable ties ("wires") but there was an annoying sound while riding the bike. You need a hose clamp. Wrap the tube with handlebar tape to protect the paint. Also, clamp on tape has a much higher co-efficient of friction than clamp on hard surface. I attached two bottle cages this way late in the twentieth century, and haven't thought about them since. Good idea, I'll try that next. The hose clamp is an underrated commodity when it comes to bikes. Not by Joerg! ;-) -- - Frank Krygowski |
#54
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drill/tap in frames
On 7/11/2018 2:38 AM, Emanuel Berg wrote:
Frank Krygowski wrote: There also seems to be a horizontal welded tab protruding from the seat tube above the chainring. (Or underneath the chainring in the photo of the inverted bike.) That may be a mounting point for the top surface of the chainguard. The chainguard also seems to have a bracket that would connect the chainguard's bottom to the underside of the bottom bracket area of the frame. Perhaps that's the spot he wants to drill and tap? The chainguard typically has a three stays. One down below, to the bottom bracket. There is a threaded hole both ways, i.e. two such occurrences. One stay front. There is usually two threaded holes on the stay/chainguard interface. But here there is more variation as sometimes it is a bent bracket screwed into the frame, also threaded with no nut. But sometimes the bracket appears to be an extention of the frame, I suppose it is welded as it is a steel frame. Then there is a stay at the back. This is sometimes a likewise extention of the frame as above (with a single threaded hole) but sometimes it is a loose part, a bracket bent around the seat stay tube, much like the component that connects the rear hub brake arm to the chain stay. If this is the case, there is no threading to it, save for the bolt that has a nut on the other side. Actually this is not what I had in mind for drilling and tapping, that was a bottle cage on the down/diagonal tube. I put it there with cable ties ("wires") but there was an annoying sound while riding the bike. So your real objective is to fasten a bottle cage to the down tube? Then you should definitely not just drill and tap the frame tube itself. A Rivnut can work. So can various clamp arrangements - yes, including screw-type hose clamps. The chainguard stay example I brought up to contradict the claim that it cannot be done because of too thin tube walls. The stays are not very thin, and besides they are screwed into the frame, so there are possibly two, at least one example how a small width would suffice. I write "possibly" because it was brought up possibly the tubes are butted. I doubt that because these bikes are commuter bikes, solid, but not optimized. But I suppose anything is possible. The normal rule of thumb - i.e. threaded portion at least equal to the diameter, and preferably 1.5 times diameter - is sometimes successfully violated. It depends on the magnitude and direction of the loads, as well as the consequences of failure. But I wouldn't try tapping the down tube of a bike. -- - Frank Krygowski |
#55
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drill/tap in frames
On 7/11/2018 2:48 PM, AMuzi wrote:
On 7/11/2018 11:42 AM, Jeff Liebermann wrote: On Tue, 10 Jul 2018 20:41:08 -0700, John B. Slocomb wrote: On Sat, 07 Jul 2018 12:33:38 -0700, Jeff Liebermann wrote: On Sat, 7 Jul 2018 11:06:52 -0400, Frank Krygowski wrote: This group has debated Rivnuts extensively. One poster claims nobody should install a Rivnut unless he has access to a complete machine shop. Others with more experience have said that the installation is easy for anyone with normal mechanical skills. That would be SMS (Steven Scharf) on one of his web pages: http://nordicgroup.us/cageboss/ Since I've made a mess with all the available technologies, Rivnuts (steel and aluminum), brazing (steel), TIG (aluminum), and epoxy glue (plastic boss on aluminum), I'll remain neutral on the matter. Hint:Â* Use steel Rivnuts on steel frames, aluminum Rivnuts on aluminum frame, and plastic straps or clamps on CF (carbon fiber). One can only suppose that those "dumb asses: that manufacture rivnuts deliberately make their product in a number of materials :-) I'm not sure about the deliberate part, but yes, one can buy them in steel or aluminum.Â* I couldn't find any plastic or carbon fiber rivnuts. And, it might be added that not knowing what you are doing is not limited to bicycle maintenence :-) True.Â* If those expounding on bicycle technology by various electronic means really knew what they were doing, they would be riding instead of pounding on the keyboard.Â* If you really want to know how things work, find someone that is actually doing the work and interrogate them for the information you need and don't bother reading books, manufacturers literature, magazines, forums, and newsgroups.Â* The only downside is that those who really know, tend to be inarticulate and have difficulties explaining complex concepts, like which way to tighten a right handed bolt.Â* However, persistence, intimidation, and perhaps bribery will eventually produce the required answer from a real expert. As I mentioned, I have successfully trashed most everything I've tried to do with Rivnuts on bicycles, and therefore have no opinion on the matter.Â* However, it might be interesting to try a simple test.Â* I could probably finance the test by taking bets on the outcome. Take two identical lengths of steel bicycle tubing.Â* Install a Rivnut in only one tube at midpoint.Â* Clamp one end in a pipe vise.Â* Pull on the other end with a Come-Along perpendicular to the tubing.Â* Measure the force with a load cell.Â* Draw a graph to show when the tubing went plastic and eventually buckled.Â* Compare results between the tubing with and without the Rivnut.Â* That should settle the debate whether Rivnuts are detrimental to frame and stay strength. I think the question isn't so much 'has the tube's ultimate strength been diminished?' but rather 'is it yet strong enough for expected application?'. Exactly. Strong enough is strong enough. And BTW, the test you're describing would be much, much easier to do in a proper tensile testing machine. Find an engineering student, get him interested, have him get permission to do it as a class project, and your data would be much better. But on the other hand, tensile strength of the tube isn't really the concern. The concern would be fatigue strength, and if we're talking about the down tube, it would be under repeated, reversing torsional stresses. I strongly suspect that you'd find no significant difference. One feature of the Rivnut is that its clamping action on the parent metal applies compressive stress. Fatigue cracks start in regions of tensile stress. The Rivnut may even make the object stronger. In theory and in absolute yes the tube is less strong. In practice, from Santana ExoGrid tandems to Bianchi thinwall tempered aluminum models, to their carbon bikes, rivnuts are not a failure point. And that's really all you need to know, apart from how to properly install them. (No, it doesn't require a machine shop.) -- - Frank Krygowski |
#56
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drill/tap in frames
On 7/11/2018 1:18 PM, Jeff Liebermann wrote:
On Tue, 10 Jul 2018 21:25:06 -0700, John B. Slocomb wrote: One might comment that a fairly large number of bridges, that subsequently fell down, were designed by the engineers of the times :-) Therefore, anything designed by an engineer will eventually fall apart. I like the logic. The problem with mechanical engineering is that problems, such as falling bridges, are easily visible. Even Joe Sixpack can recognize a mechanical failure. The fault is always with the architect or designer, and never with cost cutting contractor, sloppy construction company, defective imported components, blind inspectors, bribed officials, or the demands of the aesthetics committees. It's for this reason that I chose to go into electronics. Few can recognize an electronic problem or find someone on the design staff to blame. It's safety through obscurity. More on that theme: http://dilbert.com/strip/1994-06-10 I was once assigned the task of rationalizing countless pages of spaghetti code that was controlling various robotic workcells. The original author was probably ****ed that I succeeded. -- - Frank Krygowski |
#57
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drill/tap in frames
On 7/11/2018 12:25 AM, John B. Slocomb wrote:
One might comment that a fairly large number of bridges, that subsequently fell down, were designed by the engineers of the times Locally, the current hot problem is a historic and well-loved pedestrian suspension bridge in a park. One know-it-all claims he talked to one engineer who said "It's reached the end of its useful life" and offered to design a replacement for several thousand dollars, which would require many tens of thousands of dollars to build. Know-it-all wanted the village to hire the guy on the spot. When there was skepticism, the know-it-all (a marketing guy, BTW) brought in another engineer. Know-it-all claims this engineer said "I'd close it immediately for safety reasons." No details from either of those engineers on what might possibly fail. In fact, no direct communication from them at all. All we have is know-it-all's version of their views. Meanwhile another registered Professional Engineer examined it and reported in detail, saying that there is no danger at all, that safety factors are in the hundreds, that only minor repairs are needed, and that those can be done by volunteers. I'm a retired PE, and I agree with that guy. But we'll see which way the politics go. -- - Frank Krygowski |
#58
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drill/tap in frames
On Wed, 11 Jul 2018 07:42:26 -0700, sms
wrote: On 7/9/2018 11:16 AM, David Scheidt wrote: he was also wrong about many things. Every bike I've ever had has had holes drilled in it. Clearly, there is a range of holes that do not cause failure, and some that do. The question is where does a rivnut fall? I wouldn't drill a 5 mm hole a on 26mm diameter tube, but they work fine on large diamter ones. Did you drill those holes and install the Rivnuts or did they come from the factory that way. Were these steel or aluminum tubes? Rivnuts in very thin tubing need to be installed very carefully. Drill them with the wrong drill and you'll crack the tubing. Install them too loose and they'll spin. Install them too tight and they cause cracking. You can get away with doing this but it doesn't mean that it's a good idea. There's a reason why all the experts advise against doing this, and why it voids the frame warranty (if you're the original owner with a lifetime warranty, you might worry about this). Err.... Crack the tubing? How so? Is there some sort of magic here? Drill a hole a tiny bit larger then optimum and CRACK! The tube cracks? You just seem to delight in telling us just how little you know about what you are talking about. As you also obviously know little about rivnuts you might be interested in knowing that the Rivnut people are very explicit in specifying dimensions and even how tight to compress them when installing them. See: https://www.google.com/search?tbm=is...i h=660&dpr=1 for some examples. Searching for "rivnut+specification" will return some 65,000 hits specifying all kinds of information useful to the embryo rivnut installer. And even to the experienced. Given that the rivnut company has published their installation data for you to read. Read it. You don't have to be a dumb ass. For those determined to do this, look into the Plusnut (made by Rivnut) which is more suitable for end-user applications. Why do you say that? After all Rivnut advocates their Plusnuts as "Ideal for plastics and thin sheet metal applications where ultimate pull-out strength is required." Have you seen a lot of rivnuts ripped out of the frame tubes by sheer force? For the OP, is the chainstay even a large enough diameter for a Rivnut? What might work is using M3 x 0.25 screws. You'd have enough threads for a 1 mm thick tube. Both the screws and the taps are not cheap as these are used on high-precision machinery. Tthey also have M6 x 0.25, but I did not see any M5. -- Cheers, John B. |
#59
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drill/tap in frames
On Wed, 11 Jul 2018 07:45:09 -0700, sms
wrote: On 7/10/2018 6:02 PM, jbeattie wrote: snip it was a schizophrenic time, unlike today when we have it all together, and the technology is perfect. I tell my kids, “back in my day, people didn’t think it was a good idea to grab an electric drill and drill holes in you bicycle frame, now we know better.” Strange isn't it? After all the normal road bike frame has holes in it. Usually, as a minimum, 4 for bottle cages, one for seat tube clamp and another one or two for the derailers , quite frequently 6 to 8 more for the fenders (Oh, I forgot, "it never rains in southern California") and a couple for racks. I've even got a couple of frames with holes drilled for the shifters. Some of these frames are 25 or more years old and haven't cracked yet.... how long do I have to wait? -- Cheers, John B. |
#60
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drill/tap in frames
On 7/11/2018 11:42 AM, Emanuel Berg wrote:
Joy Beeson wrote: I put it there with cable ties ("wires") but there was an annoying sound while riding the bike. You need a hose clamp. Wrap the tube with handlebar tape to protect the paint. Also, clamp on tape has a much higher co-efficient of friction than clamp on hard surface. I attached two bottle cages this way late in the twentieth century, and haven't thought about them since. Good idea, I'll try that next. The hose clamp is an underrated commodity when it comes to bikes. No it's not. It's an over-rated kludge. |
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