[jtybt]

Need ideas on how to make a turntable to run a bead more than 3/4" at a time around a tube/base.

I have a small 2'X2' rolling welding table that fits under my bigger table. I'd like to have a removable turntable for it. Also how to attach the ground.

Any ideas?

[Rhyno21]

Well you could start by looking at Jody's video here
https://youtu.be/CXsd0AmWueU

https://youtu.be/1R3eqRui-zc

You could do that and use; gears and a chain, pulleys and a belt, shaft driven or rotating it by hand.
Now inside of my automotive collision repair class (autobody) we have a table about the size of this table in the following web address. https://m.alibaba.com/product/605970499 ... .25.6gDynI Now at this web address is about the size of table we have at school I guess the same size. The table that we have works like the photo I have attached is essentially what we have. It rotates with either ball bearings. Here is a ball bearing explained. http://www.globalspec.com/learnmore/mec ... l_bearings
or it could be two pieces of pipe/tubing one lager than the other. On welded to the table and on welded to the legs. There are four 1"X1" square tube that are short enough that if you have to move it allow you to balance it one one leg and move it more easily than just pushing or pulling. Good luck.

[Otto Nobedder]

One way to ground a rotating surface without grounding through ball-bearings or a greased bushing (both bad ideas) is to build a slip-ring and brush arrangement like in a car's alternator, but you only need one ring. You don't need actual carbon brushes. A piece of pipe (stainless preferred for a steel table) for the slip-ring. For the brush, a couple wraps of stripped 1-ought welding cable clamped back to itself tight enough for contact but not tight enough to be dragged. Lubricated with No-Ox-Ide A or similar compound to prevent oxidation and galvanic corrosion of the copper. This gives you many hundreds of fine strands making contact in many thousands of places so there's never an arc from make or break of contact.

Search e-bay for gear-motors. Look for one with enough max RPM for your needs (with the gear drive, something 120v and anywhere from 1/10 to 1/4 horsepower will be plenty. Should be a brushed motor, and not have a start capacitor), and use a router speed controller to set slower speeds.

Good luck, and please share pictures of your build.

Steve S

[clavius]

You may have seen this video of one guy's build of a small rotary welding table:

https://www.youtube.com/watch?v=ny5Xxwwpkxs

If not, it's a good source for ideas, and note how he handles the ground. It is at about 26 minutes in, if you don't want to watch the whole thing. He simply has a smooth round surface on the shaft that he clamps a welding lead ground clamp around and he restrains the clamp from turning with the shaft and lets the shaft slip through the jaws. The springs in the clamp maintain good contact and the copper surfaces slide nicely on the smooth shaft. Simple and effective.

[exnailpounder]

I am in the process of building one right now. It's not a priority but I take a run at it once in awhile. Finding the gear drive and rheostat was the hard part. I have to cast and machine a couple pulleys and I'll be done....some day

[exnailpounder]

20170414_073549.jpg (45.72 KiB) Viewed 978 times

This is the pile of parts I have amassed to build my rotator. The white base is a barbell stand that I garbage picked. The motor and rheostat are from an old track welder a guy gave me. I am using the steering head out of a scooter to rotate the table. The gears are from a lawn tractor jack that I was given but I have decided to cast a couple pulleys instead of using the gears. I have a small sheet of 1/2" cold rolled plate I garbage picked for the table. My buddy is going to machine some slots in it so I can attach a lathe chuck. I have almost nothing into this project but time as it was all given to me or I dumpster dived for it. It's amazing what you can find in the garbage if you have a good eye. Hope this gives you some ideas.

[ldbtx]

Adam Booth, abom79 on YouTube, built a rotary welding table a couple years ago. This is the URL to the first episode of the build. A later episode has excellent detail on his grounding system.

https://www.youtube.com/watch?v=9gRMNaTkjQs&t=2s

Looking forward to seeing what you decide on and build.

Larry