The golfsmith catalogue has a guide for sanding ferrels down to match the diametre of the hosel. Do you need to do this very often, or do most ferrules fit with most hosels? If I get a bunch of basic iron ferrules and basic wood ones, will I be pretty much right for most club assembly?
The basic iron ferrules I ordered form GS when they had their F&F sale needed to be turned down just a touch to match up with the hosels of the GS irons I made. I just sanded them down manually, and wiped 'em off with acetone to smooth them and shine them back up. The generic wood ferrules I ordered actually didn't fit the hosels of the fairway woods I was making. The O.D. of the basic wood ferrules was actually about 1/32" smaller than the O.D. of the Compressor fairway woods I was building. I ended up using some generic wood ferrules from Raven Golf that fit perfectly without any need to be sanded down.
I always just match them up by size. A 13.2mm ferrule for a 13.2mm hosel = no sanding, and no need for acetone except to clean off any excess epoxy from the ferrule.