I wanted to share this info with the group as it might help someone who has a similar problem.
I bought this 6" rotary table a number of years ago. I bought it new and it was Chinese made so I got it for a good price. A few weeks after I got it, I was going to put it to use and discovered the table had a tight spot on one side and was loose on the other. It felt like the worm gear wasn't concentric with the spindle. I had disassembled the unit and a cursory examination looked like the worm gear and table were part of the same casting.
I decided there wasn't much I could do about so I put it back together. I have a smaller rotary table so didn't use this 6" model very often. Today, I decided to have another look at it and took it apart. A more careful inspection revealed that the worm gear casting was separate from the table, attached with 4 socket head cap screws.
I mounted the table on my lathe in the 4 jaw chuck and centered it on the spindle in the center. Turning on the lathe at slow speed revealed that the worm gear was not concentric and it wobbled slightly. Removing the worm gear casting revealed a depression in the table that the worm gear was supposed to seat in. However, it was .020" too small and slightly off center and the bottom of the worm gear casting was slightly bevelled which allowed the casting to cock slightly when tightened down. Since the worm gear casting had hole in the center that was designed to fit over and center on the spindle, I enlarged the depression with a boring bar so the worm gear casting would fully seat when tightened down. I rechecked it for concentricity and, Bingo, the worm gear now runs dead true.
I'm hoping when I get it back together tomorrow, my problem will be solved!
Chuck
