Encoder mounting

I looked a bit further at the encoder mounting on the P&W last
night. The coupling used looks to be a bit easier for the HSM to fabricate
than some described here, the helical coupler, in particular.
There is a standard solid coupling on each end, one on the shaft of
the ball screw, one on the encoder. In between the two is a one inch square
piece of brass shim stock that looked to be about 0.005" thick or so. The
square of brass was fixed to one coupler by two rivets on opposite corners
of the square. The other two corners were fixed, in the same manner, to the
other coupler. The rivets themselves gave the square a slight standoff from
the couplers, about 1/8". This space would allow the axis of the two shafts
to be off a bit, which will result in the flexing of the brass square shim
stock in the axial plane, while still being very stiff to rotation.
After seeing it, I remembered seeing many of these in the past, some
with multiple stacked squares, each fixed to the opposite corners of the one
next to it. The stack, obviously, to take a greater misalignment than a
single square. I think that this style mount may be the best (easiest to
make) for the HSM on this list.

Brad Heuver