Quote:
Originally Posted by Bruceb
So you are saying this is something new? The old ones had a fixed shaft?
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A picture would be useful here, but I don't have any...so I'll try to explain.
The old DeWalt XRPs had a cast metal housing that slipped partially over the gearbox, and extended forward to the chuck. It contained the drive shaft, and retained it with two dissimilar ball bearings (looked like conventional ones; no angular contact or fancy stuff). We (188 in 2006) deviated from the standard NBD plan by removing the shaft, and replacing it with a different shaft that fit within the same housing, but which had a Ø0.5 in keyed shaft instead of the chuck thread and left-hand retaining screw. On the gearbox end of that shaft, we milled two opposing flats on the cylinder (so it looked something like the Ø0.375 in portion of the Globe motor shaft). Those flats interfaced with a little sintered steel coupling on the front of the gearbox, providing a positive connection that was not susceptible to small axial misalignment.
If I'm understanding you correctly, they've replaced the shaft-with-flats with a taper. That ought to work too, as long as you make sure (as we did) to let the shoulder on the shaft transmit the axial loads to the housing, so that the taper doesn't disengage.