Repurposing old rotary table as welding positioner.

[C6Z06]

Since I purchased a slightly larger Yuasa rotary table, i have no need for my old 9" Troyke BH-9. Since they are not worth a great deal on the used market, I thought I might try my hand at using it as a welding positioner.

Using it solely as a flat, horizontal positioner requires virtually no fabrication or modification. I coupled it with an adaptor to a Grainger gear motor, and hooked it up to an electric train transformer. It rotates easily and has a broad speed range in forward and reverse.

I plan to fabricate a right angle mounting plate for it so it can be used both horizontally and vertically. The motor rests perfectly flat against the mounting plate, and is held in place by the coupler. There is little to no oil in the unit, so leakage shouldn't be a problem if used vertically. I'll need to make a top plate for it to protect the top of the unit and provide some clamping holes, etc.

I happened to have several of the gear motors and a transformer on hand, so the project cost me nothing. Kind of a dumb project, but fun to experiment with.

[arizonian]

Sounds like a great idea. What will be your ground configuration? Are you going to tie the motor down somewhat to prevent torquing the motor?

[C6Z06]

Originally Posted by arizonian

Sounds like a great idea. What will be your ground configuration? Are you going to tie the motor down somewhat to prevent torquing the motor?

Not sure about the grounding. I don't want to do it through the rotary table. Any ideas?

I was going to mount the motor on a little bracket. Amazingly, when the motor is coupled to the rotary table shaft, it sits perfectly flush on the same surface the table is resting on. Under power, it doesn't budge a bit. I might not need a bracket. The table will be bolted down to the same surface the motor sits on.

It's not the end of the world if the motor gets damaged over time. I've had a case of these motors sitting for over 25 years. Now I have a use for them.

I threw this little support table for the positioner together out of some scrap from my plasma table. I know it's pretty Mickey Mouse, but it should do for the time being.

[Ironman]

This should be quite useful. As for a ground, you may just have to have extra slack in the ground cable so the work can make a full rotation with the ground clamped to it.

[arizonian]

I used a carbon block against an old brake rotor for my little positioner. Not a really good photo, the band just inside the clamp is the spring to hold the block against the rotor. Your situation is much different.

[camdigger]

Grounding suggestions

Strip a short piece of welding lead and wrap it around the work ( against the direction of rotation so it loosens with rotation.)

Make a poor man's brush rubbing on the top plate of the positioned witha block of carbon brushes or a pad of stripped copper braid.

Make a post and flag style ground to be tacked or bolted to the work. ( common on rollout wheels)

Make up a rotary ground ala Curtis of CEE https://m.youtube.com/watch?v=bIkHtYWENiA

[C6Z06]

New approach:

I have some old drill press parts on hand. I think I'll use the base and swiveling table pictured, and use a 12" long piece of 2 3/4" o.d. DOM tubing as a column.

It will allow the rotary table to swivel anywhere from horizontal to vertical and lock in place. Pin holes are in place for horizontal and vertical positions. It will also have the ability to rotate around the column slightly for heavier work. I would make an adapter plate to mate the rotary table to the drill press table.

A 1" length of cold roll round bar will extend down from the 1" hole in the center of the rotary table to provide a ground when the table is horizontal. It would be removed and the work grounded directly when used in other than horizontal.

The drill press parts should easily support the 40 lb. rotary table weight. Since the swivel axis would not be centered on the mass, I would probably mount some sort of handle to help control it.

[C6Z06]

New approach:

I have some old drill press parts on hand. I think I'll use the base and swiveling table pictured, and use a 12" long piece of 2 3/4" o.d. DOM tubing as a column.

It will allow the rotary table to swivel anywhere from horizontal to vertical and lock in place. Pin holes are in place for horizontal and vertical positions. It will also have the ability to rotate around the column slightly for heavier work. I would make an adapter plate to mate the rotary table to the drill press table.

A 1" length of cold roll round bar will extend down from the 1" hole in the center of the rotary table to provide a ground when the table is horizontal. It would be removed and the work grounded directly when used in other than horizontal.

The drill press parts should easily support the 40 lb. rotary table weight. Since the swivel axis would not be centered on the mass, I would probably mount some sort of handle to help control it.

[arizonian]

If the lower surface of the rotating table is smooth and uninterrupted, you could machine a pocket for a copper or carbon block to give a slip ring type of action. That way you could ground to the frame and not worry about arcing in any position.

[C6Z06]

Originally Posted by arizonian

If the lower surface of the rotating table is smooth and uninterrupted, you could machine a pocket for a copper or carbon block to give a slip ring type of action. That way you could ground to the frame and not worry about arcing in any position.

Another possible solution: