Work is progressing and there are even a couple of pictures to show!
The camera was not handy when I started the spindle but thats not special, just a steel tube with a bearing in each end and a shaft right through the middle. The shaft is 3/8" (about 9mm) and the ball bearings are salvaged from a photo copier.
The first picture show the base plate being trimmed using a fly cutter.

Of course no project would be complete without Sally Shaper doing her bit and here she is trueing up the side plates of what will become the tool post grinder.

The two side plates are moved to the lathe after chain drilling the rough shape of the motor cradle, here is the cradle being finished again with the trusty fly cutter.

Starting to look good, the frame is basically complete and is mounted on the compound in what will be it operating position and getting ready to drill and bore the holes for the spindle.

Holes bored, the spindle sitting in place and motor resting in its cradle..

Progress so far...

I still have to do a few things, the motor needs to be fixed to the cradle, I need to make some sort of chuck and of course I need to make pulleys and fit a belt.
The pulleys are the question, the motor claims 1/2hp at 27,000 RPM which I think is too fast for anything except very small diameter stones? So what ratios should I make the pulleys? How about 1:1 for internal grinding with the small stones? What is the slowest speed I should aim for?
As it stands the design would have the stone rotating same as the normal lathe spindle direction but if I added a lay shaft I could flip the motor and reverse the direction and get the speed down to say 3000 rpm, do I need a speed that slow bearing in mind the shaft is only 3/8"?
So many questions...
