Martin Reynolds Posted October 13, 2011 Report Share Posted October 13, 2011 (edited) So i was messing around and test fitted a bottom bracket to my Born Ultimatum 26" 2011 frame. The bottom brackets a first spurs pro (i know trials companies re-brand these). I put the drive side cup assembly in by hand (with the tool oviously, but no spanner) and got it in 90% then it started going tight where the thread stops before the end of the cup. i didnt force it and went to undo it and it went tight. I got a spanner on it, and the bottom bracket went stupidly tight. I tried working the threads by winding the bottom bracket in and out, but this didnt help. In the end i completly destroyed my bottom bracket tool. The frame is BRAND NEW, and the threads on the bottom bracket are MINT! I seriously dont why its happened Idea's people? Edited October 13, 2011 by Martin Reynolds Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted October 13, 2011 Report Share Posted October 13, 2011 http://en.wikipedia.org/wiki/Cold_welding Learned about this the hard way, doing exactly the same as you. Ended up bolting the tool into the BB, putting that in a vice, and having two people swinging on the frame to get the BB out. Soak it in release agent, bit of heat (small blowtorch), then try again, if you're lucky it'll scrap the BB but the frame will be ok... I wasn't so lucky! Quote Link to comment Share on other sites More sharing options...
Martin Reynolds Posted October 13, 2011 Author Report Share Posted October 13, 2011 http://en.wikipedia.org/wiki/Cold_welding Learned about this the hard way, doing exactly the same as you. Ended up bolting the tool into the BB, putting that in a vice, and having two people swinging on the frame to get the BB out. Soak it in release agent, bit of heat (small blowtorch), then try again, if you're lucky it'll scrap the BB but the frame will be ok... I wasn't so lucky! So BECAUSE the threads are that good and clean, they lock together? that's BULLS**T! I had the tool locked in with a crank bolt and a washer, a 2 foot 32mm spanner, and i was putting my entire weight on the frame.... thats when the tool broke. SO annoyed! Would using an impact gun help? shocking the threads? Quote Link to comment Share on other sites More sharing options...
Greetings Posted October 13, 2011 Report Share Posted October 13, 2011 (edited) Adam is probably right, happened to me on a few occasions too. Although it doesn't entirely make sense to me, I was recently replacing a Reset BB in a Sky frame, removed the broken one, put shit loads of copper grease on the new one, screwed it in and... yeah. Why did the new one weld, whereas the old one I could undo with my fingers? Edit: shocking the threads won't help, you haven't got them anymore. What Adam said about two people having to turn a frame with the bb tool locked in a vice is true, that's how much force you need. Easily 500-600Nm of it. What I did once when the bb jammed close to the end of the thread was to hammer it out and just leave the cup in. Then make cuts in the cup from the outside which allowed me to break it up and slide a screwdriver between the threads. Having done that, I had the frame tapped and all was good. Edited October 13, 2011 by Greetings Quote Link to comment Share on other sites More sharing options...
Martin Reynolds Posted October 13, 2011 Author Report Share Posted October 13, 2011 Edit: shocking the threads won't help, you haven't got them anymore. What Adam said about two people having to turn a frame with the bb tool locked in a vice is true, that's how much force you need. Easily 500-600Nm of it. What I did once when the bb jammed close to the end of the thread was to hammer it out and just leave the cup in. Then make cuts in the cup from the outside which allowed me to break it up and slide a screwdriver between the threads. Having done that, I had the frame tapped and all was good. No, the threads are there, what Adam is saying is that because both thread surfaces are so finely machined they've cold fused. Worse case i'll hammer/cut the axle out, then air demmel the cup until its breakable, but id prefer to find a less crude way of doing it Quote Link to comment Share on other sites More sharing options...
Greetings Posted October 13, 2011 Report Share Posted October 13, 2011 (edited) The moment you start to undo the bb, you'll be mashing the threads up - mostly on the cup, less so in the frame. If you haven't done more then 1 rotation in/out since it seized then you really ought to break the cup up. You won't be able to re-use it anyway, and you might save some thread on the frame. edit: the axle in a First bb will hammer out very easily, it's not 1 part with the cup. Just give it a few taps with a wooden mallet and it'll fall out the other end. Edited October 13, 2011 by Greetings Quote Link to comment Share on other sites More sharing options...
Martin Reynolds Posted October 13, 2011 Author Report Share Posted October 13, 2011 The moment you start to undo the bb, you'll be mashing the threads up - mostly on the cup, less so in the frame. If you haven't done more then 1 rotation in/out since it seized then you really ought to break the cup up. You won't be able to re-use it anyway, and you might save some thread on the frame. edit: the axle in a First bb will hammer out very easily, it's not 1 part with the cup. Just give it a few taps with a wooden mallet and it'll fall out the other end. Im pretty sure it is one part. the drive side cup contains the axle, and both bearing integrated into it. I'll break the cup up anyway, its just all a big piss off. Adam, is there any way to prevent his happening again? im guessing Grease/lubricant will still have the same effect as it can cause a vacuum? Quote Link to comment Share on other sites More sharing options...
Greetings Posted October 13, 2011 Report Share Posted October 13, 2011 Im pretty sure it is one part. No it's not. Quote Link to comment Share on other sites More sharing options...
Martin Reynolds Posted October 13, 2011 Author Report Share Posted October 13, 2011 No it's not. http://www.selectbikes.com/index.php?act=viewProd&productId=30 - The bearing races are integrated into the bb shell giving larger bearings which means a stronger bb. Quote Link to comment Share on other sites More sharing options...
Greetings Posted October 13, 2011 Report Share Posted October 13, 2011 The axle is integrated with the bearings and shell but not with the bb cups. Just twat the axle and the whole thing will fall out the other end you big pussy! Quote Link to comment Share on other sites More sharing options...
Martin Reynolds Posted October 13, 2011 Author Report Share Posted October 13, 2011 (edited) The axle is integrated with the bearings and shell but not with the bb cups. Just twat the axle and the whole thing will fall out the other end you big pussy! sod it, cba to argue. Any advice to prevent this in the future will help people Edited October 13, 2011 by Martin Reynolds Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted October 14, 2011 Report Share Posted October 14, 2011 Lots of grease, on both the frame and the BB cup. Quote Link to comment Share on other sites More sharing options...
Martin Reynolds Posted October 16, 2011 Author Report Share Posted October 16, 2011 Lots of grease, on both the frame and the BB cup. I thought this, but wasn't sure if it could create problems with causing a vacuum. I'm guessing it just works by creating a barrier between the bb threads and frame threads to stop them welding together? Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted October 17, 2011 Report Share Posted October 17, 2011 Exactly. Quote Link to comment Share on other sites More sharing options...
Martin Reynolds Posted October 17, 2011 Author Report Share Posted October 17, 2011 Update. Got the cup out by cutting 4 slits in it, and collapsing it in. Threads on the frame are a bit dodgy, will they go again with a tap? Quote Link to comment Share on other sites More sharing options...
AdamR28 Posted October 17, 2011 Report Share Posted October 17, 2011 Hmm. Hard to tell from that pic, but looks ok providing you can get it chased through. Quote Link to comment Share on other sites More sharing options...
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