Rutland Rotary Table woes

BJahn · Dec 15, 2018

I've used my Rutland 12" rotary table off and on for a dozen years and its worked perfectly. The table is always kept safe and dry.
Yesterday, when first set up, I noticed almost two degrees of back-lash.
After turning three of eight holes, it felt like the worm merely fell away from the gear; the handle spun freely and I could turn the table by hand.
I took my set-up apart, removed the table from the base and everything looks OK. I can't move the worm along it's shaft, the worm appears fixed to the handle movement and the worm seems to line up with the big center gear.
Is there some sort of exploded diagram showing how this thing is assembled so I can trace the problem further?

EPAIII · Dec 15, 2018

It would be helpful if you posted a photo of it. A closeup of the area around the crank as viewed from above would be specially revealing.

RTs often have a 90:1 work and that makes it longer to crank it around to the next setting. So many RTs have the worm on an eccentric mount that allows it to be disengaged for quickly moving the table itself to a point close to the next setting. There is usually a locking screw on the main casting behind where the crank is. You loosen this screw and rotate the bushing that the worm shaft is mounted in to swing the worm out of engagement. After rotating the table by hand, you rotate that bushing to bring the work back into engagement and the locking screw is tightened. This is about all that could bring a worm out of engagement. It is awful hard to wear the worm or bearings to that point. So check for this feature.

JohnEvans · Dec 15, 2018

EPAII has it ,sounds like the worm has shifted on it's eccentric . I have the 10" version of that table and have had no issues. But, it is fairly easy with handling to cause the eccentric to move.

DMF_TomB · Dec 16, 2018

EPAIII said:
It would be helpful if you posted a photo of it. A closeup of the area around the crank as viewed from above would be specially revealing.

RTs often have a 90:1 work and that makes it longer to crank it around to the next setting. So many RTs have the worm on an eccentric mount that allows it to be disengaged for quickly moving the table itself to a point close to the next setting. There is usually a locking screw on the main casting behind where the crank is. You loosen this screw and rotate the bushing that the worm shaft is mounted in to swing the worm out of engagement. After rotating the table by hand, you rotate that bushing to bring the work back into engagement and the locking screw is tightened. This is about all that could bring a worm out of engagement. It is awful hard to wear the worm or bearings to that point. So check for this feature.

.
agreed might be a knob to engage and disengage gear

BJahn · Dec 16, 2018

Holy smokes!! I've had this RT all these years and didn't know. Thank you guys...it does exactly like you said. Geez, I feel like such a rookie.

HuFlungDung · Dec 16, 2018

BJahn said:
Holy smokes!! I've had this RT all these years and didn't know. Thank you guys...it does exactly like you said. Geez, I feel like such a rookie.

That's nothing. When I got my first small lathe, I didn't know it had longitudinal power feed for a week or two, thought you used the half nuts to feed it longitudinally. And that was due merely to the fact that one had to jiggle the carriage a bit one way or the other to get the directional clutch lever interlock to go into its detent. No problem getting that lever to go into power cross feed, so I knew it had that.

Limy Sami · Dec 16, 2018

BJahn said:
Holy smokes!! Geez, I feel like such a rookie.

And in one way or another will do, for the rest of your life.

Good here - innit

EPAIII · Dec 16, 2018

One more thought: I would not use this feature if I were making anything that needed high precision in the positioning. There is no guarantee that you will be able to be consistent in re-engaging the worm at the same point each time that you dis-engage it. It's probably OK for making a bolt circle but this could produce significant errors if you are doing something like cutting a gear.

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