I decided to mount the arbor washers on the faceplate. I couldn't use the slots that were already on the faceplate (they weren't quite big enough), so I needed to drill some new holes. I scored a line at the correct diameter with the faceplate mounted on the headstock and eyeballed half-way between the slots. Bigger...

As each hole was drilled, I tapped it using a 10-32 tap. I made the taper have a light fit with the draw bolt removed, and turned the drill chuck by hand. As the tap drew itself into the faceplate, it could wobble a little bit, but it stayed more or less square. The faceplate is fairly thin and of a soft material, so this could have been done fairly easily by hand as well. Bigger...

In order to make sure that facing operation which was to be performed on the arbor washers was perpendicular to the axis of rotation, you need to ensure that the faceplate itself is perpendicular to the axis of rotation. Here you can see the faceplate after it was faced. Bigger...

I mounted the arbor washer using some 10-32 brass screws I happened to have. Bigger...

Here you can see one side of the arbor washer after facing. Bigger...

Now that one side of the washer is true, mounting it to the faceplate will allow the second side to be made parallel. It turned out that the #1 Morse Taper used to mount the drill chuck fit nicely through the center and I was able to clamp the washer down using the draw bolt. Bigger...

The other side of the arbor waher was faced. Bigger...

Here's a picture of one side of the finished washer (there are two of these washers). Bigger...

This is the other side of the arbor washer. In retrospect, truing the washers didn't seem to have much improvement on side-to-side wobble of the grinding wheel. I was able to rotate the wheel & washers a slight amount and eventually found a position which minimized the side-to-side wobble. Bigger...

The diameter of the hole in the center of the grinding wheel was 1", and the shaft on the grinding wheel is 1/2". These are the plastic inserts that came with the grinding wheel to adapt to the difference. Once the side to side wobble was eliminated, there was still a fair amount of wobble casued by the grinding wheel center not coinciding with the center of the shaft. This was caused in large part by the slop in the plastic inserts. Bigger...

I decided to create an aluminum insert to eliminate the slop. First the outside of a piece of aluminum was turned so that it fit nicely in the center of the grinding wheel. Here the center portion is being bored to match the diameter of the shaft. Bigger...

This is the finished aluminum insert. The grinding wheel now runs fairly true side-to-side and concentric with the shaft. I'll perform a final truing operation using a single point diamond dresser. Bigger...