Repurposing old rotary table as welding positioner

[Plasmaman]

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.

 

[TFrench]

how are you handling the earth?

 

[Plasmaman]

how are you handling the earth?

I'm working on that one. I don't want to do it through the rotary table. Any ideas?

 

[imageel]

If you search youtube for 'cutting edge engineering' you'll find a guy who does a lot of large heavy work on Caterpillar earth grading machines and the like, and he frequently repairs hydraulic pistons, cylinders etc and one video he did was turning up a custom rotating earth terminal that he usually tack welds to whatever workpiece. Whilst that method might work for larger workpieces I'm sure the same principles apply for smaller items where a G-clamp or Crocodile-clip would be more convenient earth attachment

 

[Johnwa]

Re the earth (ground ) if there is enough room on the rotary table drive shaft you could fit a couple of slip rings and brass/ copper alloy brushes. Thats what i did when I had to build a similar thing. That way you get full 360 degrees of rotation without worrying about cables.knotting up.

 

[ChaiLatte]

Re the earth (ground ) if there is enough room on the rotary table drive shaft you could fit a couple of slip rings...

Let us say the RT has worm ratio of 90:1. Putting the ground on the input shaft would wear it out 90 times as fast as putting it on the table itself. In addition, the current has to travel through the worm and wheel interface, which might not necessarily be a low resistance path.

There is a big hole up the centre of the table. Poke something up that from the bottom that is spring loaded outwards to make contact with the inside of the hole. A smaller and inverted version of the Cutting Edge design might fit there: the brass rings touching the table and the cable attached to the bolt in the centre.

However, before you go for elaborate solutions, ask yourself why a rotary ground is necessary. It only really helps if you are welding more than one complete revolution. One revolution or less, you can just clamp the earth to the side face of the table utilising one of the T-slots and route the cable so it unwinds throughout.

In the sketch at the bottom of the original post, it would not take a lot more pieces to enable the table to be set at any angle between horizontal and vertical: a base plate, a pivot and a clamping mechanism. So even if you do make it only HV just now, maybe do so with a future enhancement in mind if you ever need it.

 

[Plasmaman]

i ended up with a totally different arrangement using parts of a dill press as the basis of the machine. It can be tilted up to 90 degrees, and swiveled side to side for weight distribution as needed. The ground is a spring loaded brass rod riding against the edge of the table. The ground bracket is insulated via nylon bolts & washers. Ground clamp attaches to vertical part of bracket. Super-sturdy adjustable hand rest is made from 3 clamping shaft collars and some scrap steel bar. Works great!

 

[Fitzroy]

If you search youtube for 'cutting edge engineering' you'll find a guy who does a lot of large heavy work on Caterpillar earth grading machines and the like, and he frequently repairs hydraulic pistons, cylinders etc and one video he did was turning up a custom rotating earth terminal that he usually tack welds to whatever workpiece. Whilst that method might work for larger workpieces I'm sure the same principles apply for smaller items where a G-clamp or Crocodile-clip would be more convenient earth attachment

I’ve a man crush on Kurtis, his ability to not only fix, but improve something is brilliant.

 

[TFrench]

i ended up with a totally different arrangement using parts of a dill press as the basis of the machine. It can be tilted up to 90 degrees, and swiveled side to side for weight distribution as needed. The ground is a spring loaded brass rod riding against the edge of the table. The ground bracket is insulated via nylon bolts & washers. Ground clamp attaches to vertical part of bracket. Super-sturdy adjustable hand rest is made from 3 clamping shaft collars and some scrap steel bar. Works great!

That earth arrangement is some fantastic thinking. Very nice setup.

Kurtis from cutting edge is one of my favourite metalwork youtubers these days, since abom fell off a cliff with his content...

 

[Plasmaman]

I mounted a used Tweco torch holder I managed to pick up. Also switched to a 13 amp 12 volt dc planetary gear motor with a switching 30 amp power supply. Waiting for some steel to arrive to try out the latest setup.