In this thread about converting my 5 string bass to a 6 string...
Conversion I found a fix for those who want smaller tuners to fit larger pegholes from larger tuners...
In taking off the tuners I found the holes for the old ones were 11/16" hole size and the new ones are 9/16". No worries.
So what does the plumbing department in the hardware store have to do with bass guitars?
Turns out a 1/2" section of grey PVC (when cut to size) makes the perfect shim around the new tuners shaft.
When cut to size with a split, they fit tightly around the new tuner shaft, as well as the new tuner then fitting tightly in the headstock peg hole. Nice tight fit, no wobble and it can't move. So tight I can barely budge them at all and that's without even the top lug installed or putting in the holding screw on the back! Best 65 cents I ever spent.
Not as ideal as buying the right size tuners or having a new neck where you can drill the correct size, but I thought this might help someone in the future. Honestly, this fix makes the tuners fit tighter than even the stock ones were.