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I've been riding a vintage 531 frame bike which I've stripped and rebuilt. However, I'm having problems with extracting the bottom bracket. This has some play in it, so I really need to remove, regrease and replace the bearings. I've managed to free up the lock ring with the help of a chisel and lump hammer (to give you an idea of how frozen it was) but I cannot now remove the bearing cup as I need the correct pin wrench tool.

Has anyone any idea where I might buy a tool for such an old bike in the UK? There are 4 pin holes approximately 2cm (13/16ths)apart. The pin holes are approximately 2mm in diameter. The ones I've found that are readily visible on amazon etc are adjustable, but are for larger pin holes.

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Non-cycling-specific pin spanners do indeed tend to have fatter pins, but in the cycling section you should find something.

Park Tools SPA-2, for example, has pins just over 2mm diameter (so you should check), and the spacing is adjustable over a small range about what you need because its a little springy. I bought mine for working on a 90s Raleigh; they're not needed so often on modern bikes.

Hopefully you'll need less force than to remove the lock ring, as it's not a massive tool.

Alternatively it's possible to measure the spacing of an opposite pair of pin holes and make something from scrap metal using M2 screws as pins. That's only worth it if you've got all the tools and materials to hand

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  • Additionally - pin spanners will not survive hammering, so just don't. – Criggie Feb 28 at 21:09
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    @Criggie good point. That Park one, if you tried hammering it, would probably get its own back by springing into your face at the first hit, but the pins will snap easily – Chris H Feb 28 at 21:39
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    Might be worth mentioning that if they’re going to repack the BB anyway, there’s no harm in putting penetrating oil on the threads to maybe make it a bit easier to move the cup with a pin spanner – Andrew Mar 1 at 19:14
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In the end I resorted to the "brute force and ignorance" solution. Drastic I know, but the bike was unusable as it was, so I really had nothing to lose! I used a lump hammer and a small cold chisel to shift the locking ring by inserting the tip of the chisel in one of the lock ring grooves.
I then used the lump hammer and a 1/16" punch to loosen the cup by holding the punch tip in one of the four pin holes. This took some effort, so I expect a pin spanner would not have been up to the task! Fortunately the bearings were in racers so I didn't need to hunt around for errant bearings.
I tried to loosen the drive side cup but this seemed beyond any reasonable force! Anyhow, I managed to clean it all using a rag liberally soaked in wd40. Bearings regreased and replaced.
From the effort this took I'm expecting that the part of the internal thread might have been a little stripped! However,the play in the bracket has now been rectified and all feels much smoother!

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