Turntable Project

[Jawslandshark]

Been gathering odds and ends for something I have needed for a long time, a large turntable. I am sure somebody will guess what this now turntable was used for in a previous life. This one was taken out of service but never sent for rebuild. The gears inside still look good and everything is still sealed well since it has not leaked a drop of 10 gallons of oil.

Three phase gear motor, with VFD, max rpm on the 12.5 chuck is 12, the table is 3, I can run this thing so slow you can't even hardly see if move, still has decent torque down low. I am guessing the entire thing weighs about 1500lbs. It has forward and reverse with jog, I have tuned the vfd to accelerate and decelerate pretty quick. I have a pedal on order since that is one thing I have found I needed. The chuck comes off the front shaft and can be bolted in the center on top. Came in handy for some surface mounted bollards I was building, I can put a pipe on the front and cut almost a perfect bevel with the plasma also, don't have to worry about it tipping either. I have not finished the ground to the rotation shaft yet, just clamped to the table for now with a little extra lead.

[propanehotrod]

I've seen one of those gearboxes running a fan in a cooling tower for the chiller in a hospital. I think the one I saw was bigger. The shaft on top was around 4". I got in on it because the contractor couldn't get the hub off the shaft. The positioner looks good. What do you build that needs a table that big? I like the chuck on the input shaft, looks really handy.

[Mmock4]

Very cool,

I’m interested to see your solution for affixing the work lead to the rotating surface!

[Jawslandshark]

I've seen one of those gearboxes running a fan in a cooling tower for the chiller in a hospital. I think the one I saw was bigger. The shaft on top was around 4". I got in on it because the contractor couldn't get the hub off the shaft. The positioner looks good. What do you build that needs a table that big? I like the chuck on the input shaft, looks really handy.

It is a gearbox for a cooling tower, yes a small one, well in comparison to some others I have seen at least. I was going to fabricate a smaller table but the aluminum one seems to work just fine even for 4 inch tube on up reaching across the table. I have all sorts of parts I run with bigger bases and flanges, for pulse mig and dual shield I can weld around it without stopping now. It does take a bit to get used to keeping lighter pressure on your arms as the table is turning, I thought a little arm trolley would be handy at some point.

[Jawslandshark]

Very cool,

I’m interested to see your solution for affixing the work lead to the rotating surface!

It will be very similar to what I did on my smaller positioner I built. This seems to handle 250 amps no problem, I machined a grove on the shaft that I can't do on the big table though.

[ccogg]

Looks sweet!

Another option, besides the “arm trolly”, would be some kind of cantilevered arm rest that would hover over the rotating table in a stationary position. Maybe that’s already what you had in mind...


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[Mmock4]

I thought that’s how it might be done, but was wondering if the connection wouldn’t Arc all the time. Really interesting! Is it because the contact surfaces are so smooth that,- that doesn’t happen?

[Jawslandshark]

I thought that’s how it might be done, but was wondering if the connection wouldn’t Arc all the time. Really interesting! Is it because the contact surfaces are so smooth that,- that doesn’t happen?

It has two surfaces on the brass 90 that have been machined to contour the shaft with a little grease to keep it running smooth, the spring holds it tight. I put a load tester and 12 volt car battery and pulled 500cca through it while rotating and no problems so figured it was certified for welding! I regularly weld 1/4 aluminum on it with my sync 350 set above 250 amps and never had an issue with arcing of any HF start issues.

[derekpfeiffer]

Nice build!!! That'll definitely be handy!!!

[Mmock4]

It has two surfaces on the brass 90 that have been machined to contour the shaft with a little grease to keep it running smooth, the spring holds it tight. I put a load tester and 12 volt car battery and pulled 500cca through it while rotating and no problems so figured it was certified for welding! I regularly weld 1/4 aluminum on it with my sync 350 set above 250 amps and never had an issue with arcing of any HF start issues.

Really cool, Thanks for explaining!

[flipsk12]

That smaller positioner is really nice looking. I used that same motor on the one I built. There was a build thread before the great crash. I used a solid copper brush as a ground, the load test is a brilliant idea. Good work man