# Repurpose old rotary table as welding positioner.



## Tmate (Dec 2, 2022)

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.


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## jwmelvin (Dec 2, 2022)

Good stuff. I did about the same with an extra dividing head, stepper motor, and cheap controller/driver. I kind of rushed through it and supported the motor from a base plate; I’d like to make a coupling tube so that I can pivot the dividing head. 







It worked great for the one thing I’ve used it on so far.


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## Firstram (Dec 2, 2022)

Where did you get the controller/driver?


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## jwmelvin (Dec 2, 2022)

Firstram said:


> Where did you get the controller/driver?



I used this from Amazon:

Stepper Motor Driver Controller Integrated Board Forward/Reverse Pulse Speed Angle Control Module PLC Serial Communication for NEMA 17 23 Motor https://a.co/d/gdcrUmO


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## benmychree (Dec 2, 2022)

Nothing I see mentions having a rotating ground unit to spare the bearings form spark erosion, this is important, when I made one, I electrically insulated the rotating bearings and made a copper against steel rotating ground.


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## jwmelvin (Dec 2, 2022)

benmychree said:


> Nothing I see mentions having a rotating ground unit to spare the bearings form spark erosion, this is important, when I made one, I electrically insulated the rotating bearings and made a copper against steel rotating ground.



It’s a good point for sure. I’m not too concerned as long as the work clamp connects on the work side of the bearings. For my initial try, you can see the copper plate I used in the work clamp. A slip ring affixed to the chuck would be good and I do think I’ll make one.


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## MrWhoopee (Dec 3, 2022)

You guys are killin' me here. That's exactly the size RT I need.


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## aliva (Dec 3, 2022)

A couple of suggestions, get some anti spatter spray for the RT and put some sort of hinged plexiglass cover on the controller, sparks and slag get all over the place


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## Tmate (Dec 4, 2022)

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.


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## Tmate (Dec 7, 2022)

I got it all put together last night, and tried some welding.  It worked, but the motor isn't quite fast enough, and not powerful enough.  I ordered the pictured motor & variable speed control which is 3 times as powerful and 3 times as fast (135 rpm).  Obviously, it's going to need to be bolted down to a bigger support stand.


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## Firstram (Dec 7, 2022)

Interested in how that motor works out, I’ve been eyeballing that setup for a project.


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## aliva (Dec 7, 2022)

I posted this a while ago








						Welding Positioner
					

Not really a day project more like a couple of weeks.  This is my latest project, a welding positioner. I have a shaft and sprocket to weldup and I thought it would be a nice project. I checked the cost of a commercially available unit, but the prices are ridiculous. So why not attempt at...




					www.hobby-machinist.com


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## Tmate (Dec 10, 2022)

Firstram said:


> Interested in how that motor works out, I’ve been eyeballing that setup for a project.



Got the motor and hooked it up.  Runs quietly and smoothly.  I'm working on a mounting bracket for it now.


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## Tmate (Dec 11, 2022)

Finished up the rotary positioner today.  With the timing pulley arrangement as shown, top of the table has a speed range of zero to 1.5 rpm.  An almost infinite combination of pulley sizes are available to adjust the speed range.  Of course, the optimal table rpm varies with the diameter of the piece being welded.


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## Tmate (Dec 24, 2022)

Status report on positioner project:

The motor shown above ran fine, but had to have a wiring change to run in reverse.  Also, the capacitor didn't like it when you turned it on at a pre-set speed, ruling out the use of a  foot pedal.

I went with a variable speed DC motor from Motormakers.  It had a slightly slower top speed, but I was able to make up for it with a different timing pulley ratio.  I used an 8 amp Radio Shack power supply and a speed control i picked up from Amazon.  The setup works fine with my foot pedal.

The ground is connected to a spring loaded brass rod (brush) that rides against the edge of the table on the work side of the bearings. The bracket that holds the rod is insulated from the rest of the unit via nylon bolts, with nylon washers between the bracket and the plate below it. Ground cable is either bolted to the vertical flat part of the bracket or clamped to it.

The brass rod, spring, etc. can be accessed from the rear without having to remove the bracket.

My first attempt with the positioner is pictured below.  Travel speed was probably a bit low.  I'll have to play around with it to get the feel of it.


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## Tmate (Dec 25, 2022)

Three clamping shaft collars and some scrap steel bar make for a super sturdy adjustable hand rest.


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