drill/tap in frames
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? -- underground experts united http://user.it.uu.se/~embe8573 |
drill/tap in frames
On 7/7/2018 10:27 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? Exactly what are you planning to attach, and where? If you're drilling and tapping in (say) rear dropouts, normal practices should be fine. But if you're planning on drilling and tapping frame tubes, you probably wont' have sufficient wall thickness in the tubes. It's usually considered proper to give tapped holes a thread depth at least 1.5 times the screw diameter. So for a 5mm screw, you'd want 7.5mm of thickness. Sometimes a little less can be OK. But your frame tube walls are probably less than 1mm thickness. That's not enough. So you probably want to install "Rivnuts" instead. https://www.boellhoff.com/us-en/prod...uts-rivnut.php 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. Here's a video: https://www.youtube.com/watch?v=P_uu_ba6qAM but it's also easy to install these without special tools. -- - Frank Krygowski |
drill/tap in frames
Frank Krygowski wrote:
If you're drilling and tapping in (say) rear dropouts, normal practices should be fine. But if you're planning on drilling and tapping frame tubes, you probably wont' have sufficient wall thickness in the tubes. It's usually considered proper to give tapped holes a thread depth at least 1.5 times the screw diameter. So for a 5mm screw, you'd want 7.5mm of thickness. Sometimes a little less can be OK. But your frame tube walls are probably less than 1mm thickness. That's not enough. The stays that hold the chainguard, both from the front and under, are very thin, probably around 1mm. Still it is enough for a couple of Torx flat-headed M5 screws to hold it (1 from under, 2 front, the one at the rear is usually bolted tho with a nut on the other side). The down stay is also fastened in the same way to the frame. (I don't know how the front one is attached because you typically don't remove it. But I'll check it out.) With Loctite I suppose it'd be even more strength to it? -- underground experts united http://user.it.uu.se/~embe8573 |
drill/tap in frames
On 7/7/2018 9:27 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? Subtract pitch from major diameter, e.g., tap drill for an m5x0.8 is 4.2mm and use lard-sulphur cutting oil for drilling and tapping in steel. Yes use chainsaw oil on your chainsaw. -- Andrew Muzi www.yellowjersey.org/ Open every day since 1 April, 1971 |
drill/tap in frames
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? -- underground experts united http://user.it.uu.se/~embe8573 |
drill/tap in frames
On 7/7/2018 9:27 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? From playing with the metalworking machines I have... 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. 2) there are tap/drill charts online that tell you what hole size is needed for which tap size. 3) for cutting fluid--real fluid is best but any lubricating oil you have is way better than nothing. 4) cheap taps tend to be really ****ty--there's no other word for it. The metal is weak, the thread fit is loose and even with lube they are hard to turn in (being ground poorly),,, which makes breaking them even more likely. They aren't worth stealing. But good taps,,, cost money (just like drill bits). The $50 set at Sears would cost you $400+ from a real machinist supply place. I would suggest you buy a single spiral-point tap online, as you need them. For am M6x1mm, this is what I'd get at McMaster: part # 2703A74, $10.72 https://www.mcmaster.com/#2703a74/=1dm1s97 5) and you didn't ask, but just FYI: stainless steel is a royal bitch. It is way, way, way tougher than carbon steel. Other than an angle grinder, cheap tools simply won't cut it. You pretty much need a BIG drill press or mill and good cobalt/carbide drill bits w/real cutting fluid. I have seen posts online where people wanted to drill a hole in a cheap stainless-steel mixing bowl, and they couldn't figure out why the drill bit would just spin around and not go through. |
drill/tap in frames
On Sat, 07 Jul 2018 16:27:01 +0200, 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)? Use a drill press and a tubing drilling jig. I use one of these: https://www.trick-tools.com/Center_It_Drill_Jig_CI_1_1154 I've had bad luck using an electric drill. A drill press (or vertical mill) is best. Do the normal rules apply, e.g. to get a threaded hole for an M6, you first drill with a 5.0mm drill? 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. You should have a drill chart available. Print one and hang it somewhe https://www.google.com/search?q=tap+and+drill+chart&tbm=isch And you can use chainsaw oil, right? Maybe. High tack oil can be applied to the boss and left to harden into a passable glue. In a few months, it should be sufficiently hardened to support an empty water bottle for a few miles before it falls off. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
drill/tap in frames
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). -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
drill/tap in frames
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)? 2) there are tap/drill charts online that tell you what hole size is needed for which tap size. Yes, I have the table on virtually every calipers and ruler I have... -- underground experts united http://user.it.uu.se/~embe8573 |
drill/tap in frames
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.) -- underground experts united http://user.it.uu.se/~embe8573 |
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