Is it possible to remove too much material when chasing bb threads?
 

I am sorry if this is the wrong sub-forum but you guys know metal-work and tolerances better than anyone on the forum. :thumb:

Last year I bought a brand new Surly Karate Monkey frameset and chased the threads using the super awesome Park Tool tool from the shop I worked at. It was my first time but I am a perfectionist and it took me like 2 hours :p. I used TriFlo to lube the threads because we didn't have the lube that Park Tool recommends for chasing threads.

I can now easily screw in my external BB by hand. I have never felt a BB feel so loose before. I wrapped about four or five layers of thread sealing tape and this tightened up the BB but I fear that I may have permanently damaged my frame by removing too much material because there is a faint (but noticeable) click while rotating my pedals (even though I have stripped and built the frame with two TOTALLY different parts and groupsets).

Is it possible that I removed too much material when chasing my threads?

THANK YOU FOR YOUR HELP!!!

It seems to me that it isn't likely you damaged the frame. If they tighten down without stripping, they shouldn't move under pedal load.

Tri-Flow is arguably not an ideal cutting fluid. It's possible the threads may have been damaged, especially if the taps were dull and/or not cleared of debris. In the past, some manufacturers, e.g. Campagnolo, offered slightly oversize cups that would help in this situation, but they are quite rare now. I agree that if you can seat the cups solidly you shouldn't have a problem. Otherwise, you may need to look at a threadless cartridge or reaming and tapping the shell for Italian threads.

Unless the tap crosscut or partially cut into the original thread and chased the threads a bit wider, taps only cut to their specified size. Having a gross amount of side to side /up and down play may indicate the taps may bb cutting over the 1.375 diameter they are supposed to. Since your frame was tig welded and if done without significant heat saturation there should be minimal shell distortion. I am not a fan of park cutting tools and would only resort to using them when there is no other option. I do not know if park has shifted sourcing their cutters from Asia yet and if they have it would explain this. The other thing make sure you are tightening the bb to the proper foot pounds and then maybe more. If the threads hold you are good.
Paul

I agree that the Park cutting tools are marginal but are also serviceable in the right hands. Still it is not likely that they cut an OS diameter or thread profile unless a few things went wrong, starting with the hands holding them. Did the Bb cups strip/jump a thread during install? I have found plumbers tape to be a false solution as it's going to continue to mush about with stress. (On a tapered thread this isn't the case with complete tightening, as it's intention of use is designed around).


As to the click- We need more info to even try to suggest more. But the first thing to try is different pedals. Then lube the ring bolts. The BB's condition is also in play here. There are many threads about these issues so searching the archives might bring some light. Andy.

Thank you for the awesome replies. When I said that I have replaced everything I mean I have TRULY swapped out every part except the headset when I converted the bike from an SS Mtb to a geared monstercross bike.

Last night I removed the cranks/BB and I recorded a 30 second HD video of the bottom bracket "play" when it is 99% screwed in. The BB screws in smoothly and tightens appropriately. I will upload the video after I get home from work tomorrow.

Thank you for all of the input guys!

Ok, I took a quick video. Let me know if you think there is too much free play when the BB is 99% screwed in:

So again my question of if the BB has skipped a thread when tightening it. Does the vid show a fit that'sn the loose end of the range, yes. Is it a problem? We don't know yet. I believe the BB shell is steel (is this right?) if so the threat of thread damage is likely to be to the AL cups. Andy.

Thank you for confirming my suspicion. And yes, the bb shell is steel. The bottom bracket will thread into the shell perfectly smooth without any clicks or grinding. The threads on the bottom bracket appear flawless but it is difficult to fully visualize the threads within the BB shell.

For the third time. Have you had a thread skip, sometimes called a stripping, during the cup tightening? Have you even tried to tighten a cup fully yet? As the damage is most likely to be to be only with the softer AL cup, which is replaceable. At some point you have to try the next step. Andy.

My apologies, I thought I answered this question when I stated the following "The bottom bracket will thread into the shell perfectly smooth without any clicks or grinding." And yes, I have have tightened both cups to the recommended torque specifications without any problems. If that does not answer your question what exactly would I be searching for to determine if there is "thread skip" or "stripping"?

Two nights ago I installed a friend's crankset, BB, and pedals that he had laying around. The noise disappeared for about 3 miles and then slowly came back with a vengeance. This leads me to believe that even if the threads are in good shape there is just too much play in the BB and the creaking is coming from where the BB meets the BB shell.

I appreciate all of the help that I received. Thanks guys!

Thanks for the complete description. Threading in with no clicks or grinding isn't what wrenches would equate with a skipped/slipped/stripped thread. This is only what happens as the final tightening torque is applied, the cup's threads slip one thread within the shell and the final tightening loosens up and is redone only to repeat the slip. It doesn't sound like this happened. So many will say that you have no problem.


The cup threads in smoothly with no resistance. It seats fully against the shell's face (it does, right?) It can be fully torqued down without issue. This is pretty much the definition of a properly done fitting.


Do know that clicks and creaking can and does come from the interface of other aspects about the BB. Like the spindle's fit within the bearing's ID. Or the removable arm(s) being well secured to the spindle. Or the pedals in the arms. Or the ring bolts being dry of lube of not really tight (in how they sandwich the rings, not it their threads are tight).


If I were you I would assemble the BB cups with HD grease between them and the shell to the proper torque. Then do the same with the spindle in the cups. Some arm/spindle interfaces don't want grease. But I believe you're running a pinch bolted arm so it will want grease on the splines and draw/pre load bolt. Then ride and see what happens.


BTW I read your last post about your friend's BB install as being on his bike. But it would be fitting if you meant on your bike, not that you specified this. Either way we don't know the history of these old parts or how they were maintained or assembled yet. Sorry to be such a pain but the little details can be important. We write stuff from a view point that only we have. Assumptions on how we describe are lost on the reader who doesn't share the writer's point of reference. This isn't a problem if you're not asking for help... Andy.

You have been nothing but helpful and I am glad that you asked so many questions because it gives me confidence that no detail was missed! :)


Great! Haha. One thing that you mentioned in your last post that I have NOT yet looked into is the connection between the BB and the face of the bb shell. Hopefully I can tear into my bike again tomorrow.

I have never loved a bike more than this one and the fact that Surly no longer makes it (they changed the geo and went to 27.5 wheels) means that I really want to fix this issue but I CAN NOT STAND LISTENING TO THE CLICK 15 MILES A DAY FIVE DAYS A WEEK! :twitchy:

I really hope you get this resolved to your full satisfaction. I know how frustrating little clicks/creaks/squeaks can be.

I have a Surly Steamroller fixed gear bike--not really like your Karate Monkey, except in the frame materials & construction. It is truly a wonderful bike, and one I'd have a hard time parting with.

Don't give up. Using a logical, methodical process, you'll eventually get that thing to run quietly.

I bet the click most likely is in the drive train.
That said, you mentioned the headset has not been overhauled. Do yourself a favour open it up, clean it, re-lube etc. Then we can disregard the headset as the cause.

Seems like the threads could be rebuilt with epoxy thread building compound and that would remove the play.

I really appreciate all of the help guys!!! I found the noise!!! Over a year of riding, two full drivetrain replacements, and two wheelsets and I finally found the stupid noise. Everytime I took off the crankset I would remove the rear wheel and wipe down my frame with a rag (why not right?). When I would replace my crankset the noise would disappear initially and then come back after a certain amount of pedaling. EVERYTIME I REMOVED THE CRANK this would happen. Well, the last time I removed my crank I was in a hurry so I did not remove my rear wheel. The noise didn't disappear when I finally put the cranks back on. So it HAD to be coming from the rear end. I pulled off the replaceable drop out (which I had ALSO replaced 6 months ago while trying to find the noise, haha) and lubed the crap out of it. I put it back together, took the bike out for a spin, and no noise. I then biked to work. No noise. I biked home. No NOISE! DID I SOLVE THE PROBLEM!!!!????

I have gone on five totally silent rides so I am excited to say that I may have solved my problem!!! I am a bit embarrassed that I postponed lubing the replaceable drop out because I had considered doing this, very simple, task a month ago but I thought NO WAY could that be it! Haha.

Thank you guys sooo much for your help!!!