What pots to fit my vintage knobs?

[Piplodocus]

I've been jazzing up a guitar, and when I got it the new BKPs, I also got new replacement BKP pots. All fine and dandy.

Then I bought it some nice vintage push-on knobs. The buggers won't fit on my BKP pots (or the original ones)! So I bought some more different vintagey looking hofner type ones (NOS or some modern reproduction of sorts). These won't fit either. The hole in the knob is slightly too small.

So obviously I can go with the current fendery looking ones, but if I can get the right pots I'd probably do the pot swap to use these old knobs as they're definitely nicer for this guitar's new look. But what dimension am I looking for? Where could I source good quality ones? Else I could try mod the knobs (but they're push-on so I'd have to be careful not to overdo it and I'd lose the wiggly internal texture that I guess helps stop them slipping)? any tips?

[Dave Sloven]

Are you sure they are too small?  Split shaft pots are designed so that you can open or close the split slightly to ensure a snug fit.  Put a match stick in the split so that it doesn't crush altogether and gently squeeze it together slightly with pliers.

If that doesn't work maybe you have metric size knobs.  If you bought them from China or someone who trades with China it's possible they just fell of the back of a truck from the Epiphone factory and they are made to fit metric pots

[Piplodocus]

If I push far more than I deem sensible, they go half way on and slightly chew the inside. When I then give up I need to use something to splay out the split shaft so the old ones (original, and fender/allparts replacements) aren't loose and don't spin too freely. So far to different to account for sligh snugness difference.

The vintage replacement knob sets are from Teisco and Hofner, so if they're japanese/german respectively, then I guess it'd make sense if these were metric shaft pots instread of the usual imperial fender/gibson and other US company ones.

So, where would I find good quality metric split knurled-shaft pots? Most parts shops don't seem to ever mention whether they are imperial/metric and just state smooth/split or long/short (so I assume imperial by default).

I can just go googling for any old metric pots if the theory is correct, but that doesn't mean they're any good for guitars...

[Piplodocus]

These any good...  http://www.axesrus.co.uk/1-x-CTS-Pot-Split-Shaft-Metric-Size-p/cts59met.htm

[Piplodocus]

Guess I'll find out - I've bought some!

If they turn up with a narrower shaft for European/Japanese guitars, but the head is still imperial for US knobs I'm gonna be annoyed!