Unimat-SL DB-200 Motor/Spindle Bracket Modification

I may have said in the previous post that there would probably be no more projects on this lathe. Well that didn't prove true. I decided to do some whittling on the motor bracket. The reason for this bit of work is because the hunk of steel that encompassed the spindle was way too stiff, and the screw that clamps the bracket to the main spindle needed to be tightened a bunch for the clamping action to do its job. I figured if I removed some metal on the bracket, it would be easier to clamp. Here's what I started with. The red is the main part I planned on cutting out, plus a few minor touch-ups.

This next photo shows how I secured the bracket in the Smithy mill. It is very far from ideal but worked fairly well. I found a piece of 1-3/8-inch diameter bar, the same size as the spindle hole in the bracket. I then clamped the bracket onto the bar using the clamping screw. The bar was then mounted into my dividing head.

This next photo shows the finished product. The clamp is much easier to engage onto the spindle now.

Here's a shot of all three motor bracket iterations, left is what I started with, center is cleaned up, and on the right are the finishing touches I did today.

And the next couple photos show the bracket back in place.

I happened to spot my vintage Craftsman RPM gauge sitting on the table I was working at so I measured the RPM of the spindle. It was 2,500. The manual I have says the speed should be 1,600 with the large belt in the middle pulley on both the motor and spindle stepped pulleys and with a motor speed of 4,000, which is what the manual states. After a bit of cipherin' (ala Jethro Bodine), the motor RPM on this lathe must be around 6,250, not 4,000 as is mentioned in the manual. To use the chart in the manual, I need to multiply its numbers by 1.5625 (2,500/1,600) to get actual RPM of my lathe spindle.