The new spindle motor and pulleys are finally installed and working (and all the gearing and oil is out of the head).
As you can see in the picture below, I ended up with two cap screws to hold the spindle pulley in place. This is because I did a poor job on the bore and the pulley had 0.020″ runout. I just added the second cap screw and got it to within 0.002″, which really reduced the noise level.
The next step is to run the spindle up in steps and see how the temps look. It’s currently running the stock bearings, but I do have replacement angular contact bearings that are good up to at least 8k RPM with grease.
After that I want to try out some commercially available pulleys as I put together the BOM and instructions for the plans I’ll be selling.
The biggest benefit by far is the difference in noise level. It now makes 77 dB at 3k RPM, compared to 85 dB with the gears in place.