Rotary Table Backlash

[MyLilMule]

I picked up a John B. Stevens 8" rotary table last year, spent some time cleaning it up (see my video below).

How much backlash is too much for a rotary table like this? I think I can squeeze a little more out of it before it binds the shaft, but not sure if it's worth the hassle.

 

[Manual Mac]

I had my 6” RT apart yesterday to drill & tap so I could install an adjustable angle zero pointer.
while it still had plenty grease on the worm gear, the ring gear & the worm were dry & showing showing signs of wear.
in my quest to remove all backlash, I had gone *too* far.
when I put the RT back together I left a few thou backlash clearance , hopefully this will prevent wear.
This works for me.
cheers.
EDIT: while my *budget* RT has ball oilers, I need 1 more (I guess) to lubricate the worm gear?

 

[woodchucker]

damn, couldn't you have given a time mark so I didn't have to watch the whole thing? You can get more backlash out. It's pretty good, but I think you need to adjust your stops a little more. It didn't look like the worm was worn. if that eccentric can engage a little more on the gear you might get close to 2-3 ticks. You are already pretty good, but there's more that can be gotten from it I think.

 

[RJSakowski]

My 12" Enco RT has about 10 seconds of arc backlash when the worm preload is tightened. Backing off the worm preload from the stop by .004", the backlash increases to around 30 seconds of arc and the worm can be turned bur with some difficulty. Further backing off to .008" increases the backlash to around 1 minute of arc. This is where I would set it if I were machining an arc. I always approach a final position from the same direction so that backlash is taken out of the picture.