Integrating Encoder Into Gearbox

[InFlight]

Originally Posted by scottandme

You're confusing the shaft diameter tolerance with TIR. The H1 encoder has a maximum TIR of 0.006", and the shaft itself is between 2 and 6 tenths undersize (-0.0002 to -0.0006).

So the shaft diameter has a tight tolerance, but the encoder might have up to 6 thou of runout, an order of a magnitude larger than the shaft diameter tolerance.

In any case - using a reamer would give you a nice clearance fit, and then use a set screw/retaining compound/whatever to hold.

If your lathe is poorly setup, and doesn't drill holes on center:

1) Fix that
2) It doesn't matter - since the 1/32" piece of lexan holding the encoder will happily flex/float if the encoder has any axial/parallel misalignment. Same idea as using a helical beam coupler/flexible coupling that can deal with axial/parallel/radial misalignment.

If you measured the current runout of your own lathe you might be surprised. Most will be over the 0.006 value which was my point.

If your drilled off center; your applying a bending load into the resolver shaft every rotation with direct mounting. At 100 rpm your going to be challenging a floating mount, and getting higher loads in the resolver bearings.

This is the reason many of us prefer alternate non-direct mounting. For close mounting a no contact magnetic rotation sensor would make far more sense.