Hoyt McKagen <batwings@i-plus.net> wrote

frank booth wrote:
> The reason tapered couplings are used in feed motor assemblies has to
> do with direction reversal. Shafts which change direction are never
> coupled using keys or splines.

Just not true. A good many shafts in machine tools reverse and still use
keys. The example most readily at hand is the bull-gear-to-spindle in my
South Bend. Same goes for the lead screws. I've seen nearly nothing but
keyed shafts in any machine tool for that matter. Not knocking collets
for the job, have seen several MC motors with the primary drive on
collets or taper (Husky and CZ for two) and there is indeed nothing more
secure, just manifestly not necessary.

--

Best wishes,

Hoyt McKagen