Classtime 

I have a 73 Raleigh Competition with the original TA cups threading in and out easily. A Shimano adjustable cup goes in and out fine but the drive side fixed cup won’t. I cross threaded it trying to use the shimano but the T.A. Still works fine. My LBS with the Campy tools and an old shop owner to use them wouldn’t try to chase the threads because he feared they would be ruined and then what. I want to use a shimano BB and a Deore crankset with the two small rings to haul my trailer. (Plus the original NDS TA crank arm is cracked.) It doesn’t make sense that the TA BB fits fine but not any of several Shimanos. Next step will be another LBS but what the heck?

repechage

Shimano depending on the vintage did evolve their thread form. Maybe what you want to use is ISO and this frame predates that.
also, Raleigh did produce these with 24tpi and 26tpi…
for that, best to check both TA parts carefully.

should have mentioned English is 1.370”, ISO is 1.375”

abdon 

There are thread less bottom brackets you can use. Or rather the cups thread into the bottom bracket themselves, bypassing the shell. To take out you'll need two bottom bracket tools as both sides will need to be held at the same time.

https://www.amazon.com/Sunlite-Threa...004E3QNXM?th=1

If you mess around with old bikes eventually you'll have need of one of these, either by your own fault or somebody else.

juvela

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if you have access to a die grinder or grinding wheel you can use an old cup to create a thread chaser

this has come up numerous occasions here on the forum

here is an image of an Italian fixed cup which was turned into a thread chaser by this method



such tools cannot serve to cut new threads but can be employed to reform damaged ones


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spclark 

Interesting thread (pun intended, kinda).

I'm looking to put a modern Velo Orange BB assembly into my vintage MBGR's 67.84mm long (2.670") barrel down there.

Just not yet certain what the thread profile is: English or French?

The cups screw in & out fairly easily, never crossed up, none have anything I can find to indicate threading.

Taking my mic' to 'em I came away with DS-side's thread OD @ 34.81mm (seems to taper towards the inner end), ND-side's 34.77mm (similarly tapered.) Repechage added those inch dimensions, converted they're 34.798mm & 34.925mm respectively.

My lock ring threads easily onto two Campy Record hubs I have, I have come to trust as having English threads. Those Stronglight BB cups will thread into three Maeda/Suntour Perfect FW hubs I've collected as 'donors' for the cogs they brought with, up to a point.

Any hints or suggestions?

Classtime 

If the 6200 Shimano adjustable cup is a nice fit, can't I assume that the shell's threads are close enough for the fixed cup as well?

I lied in my first post: I loaded up my Shimano fixed cup with anti seize. It turned nicely by hand for about 4 revolutions and with a wrench back and forth to overcome a few hangups, I got it on with a small uniform utility knife blade gap all around. If I decide to remake this Comp with paint+, maybe I'll have a Cycle BB tool and go at it.


It was attached to a nice B17.

mpetry912 

this is correct, there were some Raleighs that had 26tpi which I think is an older english standard that predates BSC

/markp

merziac

Assuming the Shi*mano DS cup threads in fine elsewhere, I would "burnish" dull/smooth out the threads on the wire wheel bench grinder and see if it helps, if not make a chaser out of it and use anti seize, 1 step forward, 2 steps back very carefully to get there.

I would also start by scribing the shell threads mm by mm with a right angle pick, harsh light and strong readers to get any debris or damaged threads cleaned up the best you can.

I have never had to have anybody else chase a BB or failed to resolve any issue including 2 PX-10's that had BSA cups forced into them.

nlerner

This is why I bought a relatively cheap Cyclus BB threading tool: https://www.merlincycles.com/en-us/c...ool-92193.html

I use it to clean up threads given any sign of cups being stubborn.

Classtime 

Good News.

This will be in my letter to Santa.

3alarmer 

...it doesn't sound like some sort of period authenticity is in your program. I have my own BB taps here, but if I did not, I would just buy a sealed unit BB in the proper spindle length, preferably one with nylon/plastic cups. It should conform to whatever threading you have remaining in there on the drive side, with little problem. Aluminum alloy cups on a sealed unit will work, too, but then you might have some problems down the line with removal, if it corrodes in the steel BB shell.

oneclick 

Some cups have more taper to their threads than others.
If you cross-thread a cup with little taper, it'll damage the threads at the beginning, not at the end, because it won't get there.
If you then try a cup with a long taper, it may find the undamaged threads further in, and those will guide it in properly.

Some bbshells have deeper threads than others.
If the innermost threads are dirty or rusty or just not cut deep enough, a cup with little taper may appear to bottom out when it reaches the end of the threaded potion.

I just went through a very similar situation fitting a bb cup to a Romet Sport, mfr'd in Poland.
The bb shell had poor threads for the adjustable cup, I had to bolt the pin-tool to the cup so I could turn it with enough force to clean them up enough so the cup went in far enough.
It also had been cross-threaded (previously) and the first few goes with a Shimano cup (not much taper) it found the wrong set; back-and-forth a few times with a long-taper cup re-formed the outer threads enough that it eventually went in as it was supposed to.

Swearing helps.

merziac

Well I get it and they can and may get the job done but the old guy at the LBS knows a thing or two.

Those taps in the right hands can solve problems, the wrong hands and or lack of patience, well.......

I have never needed them and more importantly never want to remove any material unless absolutely necessary, you cannot easily put it back and many BB shells are sloppy beforehand even though they cross threaded and may have seemed tight.

Homebrew01

I have done that on pedal threads. Worked well.