Originally posted by Bart Veerman
Chances are they'll work just fine without them washers...
No reason to change anything.
Turns out I had several flat/thin hex nuts such as go on quarter-inch jacks, but no washers or trim rings with them. All the washers I keep with instrument parts are either nickel or chrome plated actual tuner washers or stainless steel from the hardware store and all are about as thick as what's on the banjo now.
FWIW, I've had good luck enlarging a hole by finding a drill bit close to the existing hole size, inserting it into the peg hole and twisting it around By Hand. No drill. You can take out very small amounts of wood with low risk of damage.
'1992 Gibson RB3' 1 hr
'KERSHNER UNIQUE' 1 hr
'Crowe model Gibson' 2 hrs
'Roy's own finger picks' 3 hrs