I'm making a set of one piece scales and have some 1/8" barrels and torx head screws for the pivot - I'm aware that drilling out the pivot to accommodate the barrel is beyond an ordinary HSS drill bit so can anyone advise the type that I should be looking for? Also any advice on just how much bigger than the barrel would be appreciated.

i would prefer a generic spec rather than specific makes or retailers as I'm in the UK - as you can probably work out.

thanks in advance.