According to :
Loren wrote:
If you were in my shoes.. what would you do?
A shaft is needed for a machine, 1.5" dia, but with a collar at the
middle of it. ...
Thanks for the advice
- Loren

I'd look real hard at a separate collar clamped or pinned to the shaft.
If you use a taper pin it can be retightened if it works loose.

And to add to the complexity -- you mentioned keyways in another
branch of the thread. How close do they need to come to the collar?
Given that, I would be tempted to make the shaft with a full-length
keyway, and fit the collar to it with a key to prevent rotation, a
setscrew to hold the key in firmly, and then the taper pin to lock it at
a given point along the shaft.

This way, the keyway can be cut in a single pass with a
horizontal milling cutter -- a lot less trouble than trying to make a
keyway up close to an integral collar.

Good Luck,
DoN.
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