Regrinding a drillpress spindle

Video to go along with the project:
Regrinding a drillpress spindle
(Link opens on Youtube in new window.)

A customer asked me if I could regrind the arbor of a drillpress spindle. After some inspection it was clear that the complete spindle with its bearings, mounted in the quill was running well enough to be reground running in its own bearings. This method is widely used to grind precision grinding/milling/dressing spindles. But why not also use it to regrind a „lesser“ spindle?

The spindle has a B-taper, thats a shortened morsetaper (Thick or thin end of the MT, depending on the size of the B-taper).
The B16 taper I had to grind here is the smaller end of a MT2 taper, easy to prove with a male MT2 arbor against the supplied drill chuck with the B16 internal taper.

The tool and cutter grinder is the ideal machine for this task. The quill was mounted in two magnetic prisms and set for half the taper angle using a sine bar.

The spindle is driven via an O-ring off the workhead. A small delrin pulley is clamped to the input-end of the spindle, a second pulley with a 6mm shank is held in the workhead.

The taper got ground with a 80 grit aluminium oxide wheel, thats a good compromise between heat input and surface finish.
If to much heat is put in the work, the part grows in diameter, into the grinding wheel, which has more heat input as a result, which leads to something failing.