Self Build Bamboo Bike Frame Kit Build Thread

[Tenacious Sloth]

Don't become overly paranoid and lose your nerve just because it went bad the first time. You say you don't want to force it, but how much "force" have you given it? It will take alot to strip those threads, alot more force than you can put in by accident. Make sure it is as aligned as it can be and give it a fair bootful. - That's my penny anyway.

**Edit: sometimes problems occur when people care and overthink things, sometimes you really need to not care

Hmmm. Easy to say when it’s not your BB Shell.

You could always send one of the shells and the B.B. back to them and see if they can get them in. Last resort though.

I’m enjoying your posts. Keep up the good work.



Graham.

 

[Gary E]

As you've tried 2 sets of BBs and you've confirmed it's the correct thread (by fitting the RH thread side) I'd say that it's down to the manufacture of the shell. As you've already said; this isn't a massive company and so all of the items you've received so far are likely from the same batch.

As far as forcing the BBs in is concerned, I'd be inclined to leave this as a last resort - remember at some point in the future, once the bike is complete, you're likely to want to get them out again. You ideally want the BBs to come out of the fitting rather than the fitting to tear out of the Bamboo frame!

It's worth having a look at the thread and cleaning if required and you could try greasing them and putting them in as it looks in the picture that you're doing it dry. This doesn't have to be the final assembly (so you can use as much as you like then clean it up again later), once you've managed to fit the BB once, you'll hopefully find that the BBs are better fit. Don't force it and do it in stages - every half turn or so take the BB out and clean out any swarfe that may have built up. If you have a good bike shop near you they might have a thread tap they can run down the threads to clean them up (if they're not too far out).

 

[fixedfixer]

Local bike shop will run a tap through it to clean up threads. Should then spin in and out nice and freely. Althernative would be to make a tap from an old cup - I copied and idea I saw on another forum.

 

[Deleted member 26715]

Or at least take the unit you are trying to screw in to LBS & ask if they can screw it into a known good unit to test that, if that's okay then you know the issue is with the one bonded in.

 

[chriswoody]

Thanks folks for the input, much appreciated. I've been having another go this morning and the left hand side goes in an absolute treat, but the right hand one will go in one turn relatively easily and then bind completely. I've tried the other cup in there gently to see if the've accidentally put in a clockwise thread, but no joy with that.

The bottom bracket shell is strongly bonded in to a Bamboo Frame in much the same way that a Carbon Fibre framed one is. So once it's it there's no way to remove it, which is why I'm keen for it to be correct from the start. I've actually pushed it as far as possible to the extent that I needed to clamp the BB removal tool in the vice and use a lot of force on the shell to remove the cup.

I've eliminated the dirty threads problem by using a brand new bottom bracket and the shell from the bike is brand new as well. I've had a good look at the shell threads and there's no swarf in there, it's actually really well machined with no visible problems or burrs, it just doesn't work!

As @Gary E has said because these are all small run items they must be all from the same batch. However I would expect that there must be more of them out there in the wild so maybe someone else is having the same issues.

There's a really good old school bike shop not far from here who've helped in the past, maybe I'll swing by shortly and see what they say. One issue is that you can't clamp the shell into a bench vice to work on it, because you risk deforming it.

 

[Deleted member 26715]

It could just be the wrong thread, imperial against metric, or tpi (threads per inch) or I suppose there is a new acronym for metric (I'm old)

 

[Gary E]

It could just be the wrong thread, imperial against metric, or tpi (threads per inch) or I suppose there is a new acronym for metric (I'm old)

If the other side hadn't gone in this would have been my guess too. However they're unlikely to use 2 different thread patterns in the same BB Shell (obviously one is LH and the other RH). Customer service (from what you say so far) seems excellent so might be worth another call? They'll likely be happy to hear from you if it saves them having to recall/replace components from future sales?

 

[fixedfixer]

use an old cup from a cup and cone type in the good end with a nut and bolt through it (like my photo) . Then clamp the bolt in the vice and operate on the other 'bad' end. As you say don't clamp the bb shell in the vice it WILL deform.

 

[Illaveago]

It could just be the wrong thread, imperial against metric, or tpi (threads per inch) or I suppose there is a new acronym for metric (I'm old)

It sounds like you could be right in that the cup goes in part way and then seizes. One way of confirming that would be to try a cup of a different thread to see if that works.
A better solution might be to return the part for a replacement which works rather than damage the existing one.

 

[chriswoody]

It could just be the wrong thread, imperial against metric, or tpi (threads per inch) or I suppose there is a new acronym for metric (I'm old)

Thats been going through my mind as well. It does seem implausible, but the way the problem manifests itself is just like that.

There's some really good suggestions here and @fixedfixer I like your makeshift tap, thats a definite one to try for the future.

However, given that the shell is not yet fixed into the bike and how easy it will be to pop them in a jiffy bag and send them back. I think this time that's the route I'll take. It's been good though to hear peoples thoughts and I appreciate you taking the time to voice them it's helped to clarify that I've not overlooked something. As I said at the beginning of the thread I'm in no rush with this project I'm enjoying myself and there is still some work I can do in the meantime. I'll drop them an email now and see how I get on.

 

[fixedfixer]

@chriswoody I used a good quailty cup and cone set, cut across with a dremel drill and then put a 'shamfer' on one edge to create the flat. Cleans up threads fine - wouldn't cut them obviously. Has been great on bike restorations and cleaning up spray painted frames. As said, not my original idea so can't take credit for it.

Keep posting the build thread. I must get back to building my USS recumbent and updating my thread - but not had to much time recently.

 

[Randy Butternubs]

the right hand one will go in one turn relatively easily and then bind completely

Sounds like the thread pitch is wrong except that the left one goes in fine. Therefore, I think you have probably cross-threaded it slightly (not a big deal): the first turn of thread has cut a new path and will turn in and out quite happily but when you try to screw it in further the combined resistance is too much. As I said before it is easily done when screwing in these broad, shallow things. I could be totally wrong of course .

Time to take it to a bike shop I think: it's too hard to diagnose this kind of thing remotely.

 

[Crackle]

Take it too a bike shop, they'll have a tool to clean up the thread and it takes moments. It's not unusual for a new thread to be wrong and need cleaning out. If you try to do it yourself you might foul it up.

 

[chriswoody]

Thanks again folks for your input. So small update time. I emailed the Bamboo Bicycle club this morning and they replied within the hour!

Anyway it seems that there is an issue with the current batch of BB shells and their chatting to their supplier over the issue. Strangely it only seems to affect some makes of Bottom Bracket, Tange brackets have no issues whereas Shimano are causing problems. They've found that some brute force and ignorance will get the cup in and clean the threads up, at which point it should then screw in and out with no problems.

So as some of you have recommended, I just need to get some form of tap or use an old BB cup, if I can work out how to hold the shell without crushing or deforming it, then I'll give it a go. I can also give one shell to a local bike shop and see how they get on. They've also promised to send out a working shell if I want. So I figured I can't lose anything now by at least having a go with the shells I've got.

 

[raleighnut]

Thanks again folks for your input. So small update time. I emailed the Bamboo Bicycle club this morning and they replied within the hour!

Anyway it seems that there is an issue with the current batch of BB shells and their chatting to their supplier over the issue. Strangely it only seems to affect some makes of Bottom Bracket, Tange brackets have no issues whereas Shimano are causing problems. They've found that some brute force and ignorance will get the cup in and clean the threads up, at which point it should then screw in and out with no problems.

So as some of you have recommended, I just need to get some form of tap or use an old BB cup, if I can work out how to hold the shell without crushing or deforming it, then I'll give it a go. I can also give one shell to a local bike shop and see how they get on. They've also promised to send out a working shell if I want. So I figured I can't lose anything now by at least having a go with the shells I've got.

If you stick an old steel cup in t'other side will that stop the tube deforming.