Tuesday, May 8, 2012

UABMM2 Shaft Assembly

The first thing I need to do is make a shaft key.  The key slot in the split taper bushing.is 0.125 inches square.  The closest key I have is 0.150 inches square.  So rather than drive to the hardware store and buy another one, got plenty of the wrong size, I'm just going to modify one that I have.
I'll just chuck the key up into the vise, and grind it down to the right size.  Then test fit it into the groove.

Next I want to make an 0.125 inch groove in the shaft.  The problem I have is how to hold the shaft.  I need to clamp the shaft to the table before I can machine it.  It would be nice to have a set of V Blocks to do this, but I don't.  So, gotta make something similar.  I have some Steel bar stock that I can use to make a U Block.
 The shaft is 0.500 inches, so I put a half inch hole in the 1.000 inch by 0.500 inch barstock.  Then cut it in half to make two half inch diameter U Blocks.  They will help me hold the shaft while I cut a groove in it.
Then I sliced the two U Blocks off the end of the bar stock.  I'll go clean them up and see how they look.
The U Blocks support the bottom of the shaft and the Table Clamps hold the shaft down on the table.  The radius in the U Block provides the friction to prevent the shaft from turning when the tool hits it.  The plan was to mill a 0.125 inch groove into the shaft.
The plan changed when I snapped off a 0.125 inch Cobalt mill, Doh!  So, rather than a slot I just made a flat with a 0.500 inch mill.  Really I should have used a High Speed Steel Mill instead of a Cobalt Mill.  Doh!
I was careful to sneak up on the right depth so that the fit is tight and needs to be pressed into place.  I don't want a floppy split taper bushing, especially since this one is holding the UABMM2 Rotor.
Then I'll take a piece of pipe and tap the split taper bushing into the right place.  Then the split taper bushing is solidly mounted on the shaft.  More rigidity for the Rotor is always a plus in this application.
The last thing was to drill a couple of holes in the Rotor to bolt it to the split taper bushing.  This locks the Rotor to the shaft, and makes the whole assembly have the rigidity of a single piece.
Next I need to re-install the magnets on the Rotor and get back to testing.

1 comment:

  1. I very much like this. No matter what the scientist is improving his/her skills by the search for greater understanding. Ever greater, ever stronger, onwards towards excellence! Keep it up!