While waiting for various bits and parts to arrive for my dovetail slide/hardinge lathe project, I started thinking of the *next* project idea, heh heh.
I have a spare sherline spindle headstock leftover from some project or another, and I think it would be fun to modify it to be an ER-16 or ER-32 collet spindle. Rather than start from scratch machining up a whole new spindle, I was wondering if it might be possible to adapt one of the ER-16 or ER-32 straight shank collet chucks? Enco has quite a few listed in the sale flyer, models with up to a 7" length straight shank in both 3/4" and 1" diameter. Made in the USA, and pretty cheap at $70 or so.
Assuming you could get bearings simillar to the sherline bearings to fit the OD of one of these shanks, and the ID of the aluminum headstock, how would you do the preload? Perhaps grind a groove for a circlip toward the front of the collet chuck shaft and somehow machine threads in the (hardened?) shaft for a preload nut? Hmmm, how long ago was it that I said I didn't need threading capability on my lathe??? two weeks? Sigh.
Rick