crazy sherline spindle mod - opinions?

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
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.
Reply to
Loading thread data ...
Interesting idea; the 3/4" OD collet chuck would almost fit in the stock Sherline bearing. Still only gives you 3/8" through. I don't offhand know the tradeoffs for a "thin-walled" bearing in terms of accuracy and life.
Another WA idea would be to get the 1" OD chuck, at whatever length you prefer, then bore and thread the back end to fit on the stock spindle. It would at least give you the ability to hold a short piece of over-3/8" stock, although it might need a steady or even a bearing to support the overhung chuck.
Seems like the answer to a relatively rare need, maybe.
Reply to
Fred R

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.