Re: [Amps] Want to use a knob with a 3/8" opening on a 1/4" shaft.

[Peter Chadwick]

I can't remember who wanted the specail sleeve, but if you still haven't got one, drop me an email (g3rzp at g3rzp.wanadoo.co.uk) and I'll turn you out a couple over the holiday. You'll need to let me know what grub screw holes are required.
Twist drills aren't the best way to get accurate holes that don't wander off centre. That's why  they use the special single flute drills for gun barrels. A spade drill is good, too, but has its own problems..
73
Peter G3RZP