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i have the goods to construct a rotary positioner... how would you do it?

tnmgcarbide

Diamond
Joined
Jul 6, 2004
Location
N. GA- 33.992N , -83.72W usa
^6" Whiton 3-jaw , massive ball bearing thing. 2"-8 threaded hub .
12x12 x 1/2" hot roll plate. honda 12v right angle gearhead window motor.
Square -D SPDT pedal factory safety switch... and tweco-CABLEHOZ finely braided
copper ground. and 4Amp 15v power supply .

how /where to start?
 

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Motor/gearhead is way too small for that chuck.

I will post pix of mine tomorrow.

Thru hole is nice, just had to tear mine all apart the other day to drill the main shaft out to accommodate a 1 1/2" shaft.
 
^6" Whiton 3-jaw , massive ball bearing thing. 2"-8 threaded hub .
12x12 x 1/2" hot roll plate. honda 12v right angle gearhead window motor.
Square -D SPDT pedal factory safety switch... and tweco-CABLEHOZ finely braided
copper ground. and 4Amp 15v power supply .

how /where to start?

De-grease, electro-strip, and copper-plate the piss out of the chuck to reduce weld-splatter sticking to it?
 
Is that winder cranking motor rated for continuous duty ?

Gonna need to think about tilting it too....
 
honda gearmotor might be deceptive . i think it should work ok. pwm, or resistive - whatever.
it has plenty of torque. up to maybe 10# .

belt drive? rim drive? what about it getting hot as hell ? decouple the chuck
and workpiece ?

this is all new to me.... why i've asked.
 
First off, figure out what speed you want the chuck to run at.

Work from there.

I would suggest bicycle chain, sprockets with many speeds are readily
available.
 
honda gearmotor might be deceptive . i think it should work ok. pwm, or resistive - whatever.
it has plenty of torque. up to maybe 10# .

belt drive? rim drive? what about it getting hot as hell ? decouple the chuck
and workpiece ?

this is all new to me.... why i've asked.

Tilting, as Doug mentioned, might make this harder, but so long as you have space under the top of the welding table, the drive should stay cool enough with even a modest length of shafting. Bicycle-type chain can stand more heat than elastomers. Both need shielded from weld spatter..
 
I find there is not much weld splatter, seeing how 99% of this welding is done continuous MIG welding.

I have been around many commercially built machines, and have not seen copper plating anywhere.
 
I found one of these with a speed controller on eBay for cheap. I used roller chain and cut the speeed in half. Works perfect for my job. Also I use it to flame cut steel circles to make flanges. DAYTON AC'/'DC Gearmotor 115VAC'/'DC Nameplate RPM 8 Enclosure Open Vented - 1LRA5'|'1LRA5 - Grainger

Old Day Job used a similar Dayton one in a product. It had the mounts arranged so the shaft was vertical, so that might be the better fit, here.

Cheap enough - about $40 ea. back in the 70's. Lasted for ages.
 
Do you have an old wire feeder laying around?

I find the old feeders are real tough and have a great DC drive in them that's easy to adapt.

The Rotostar positioners are made near me and I've used them a few times. I would try to copy that design if you were going to make one. Owner sells a shitload of those things.

No copper plating, rubber timing belt, carbon brush on back of chuck, tube through bushings w/zerks for the spindle, several sets of overlapping drilled holes and a pin for angular adjustments. The body is all 1/2" aluminum flatbar milled, bolted, then powdercoated and the critical surfaces finish machined after coating.
 
i'm too much of an ignor-anus to understand steppin' motors . it would involve
"boreds" and such ...... i prescribe to the "KISDF" as in
"keep is stupid dumbfuck"

Well, if you just want to watch things spin in circles, A ceiling fan will do. Most of 'em are three speed.
 
Do you have an old wire feeder laying around?

I find the old feeders are real tough and have a great DC drive in them that's easy to adapt.

The Rotostar positioners are made near me and I've used them a few times. I would try to copy that design if you were going to make one. Owner sells a shitload of those things.

No copper plating, rubber timing belt, carbon brush on back of chuck, tube through bushings w/zerks for the spindle, several sets of overlapping drilled holes and a pin for angular adjustments. The body is all 1/2" aluminum flatbar milled, bolted, then powdercoated and the critical surfaces finish machined after coating.

actually...yes . i do have an old feeder lying around..two of them...

push-pull MK-Cobra-matic feeders . they are set up to run from the connector
on a Miller CP- power supply.

never crossed my skull.
very brilliant!
indeed. !

i will look at the guts and see.
that is great news.
thank you.......


that's why we ask questions... to get reminded of shit that's staring us blindly
in the face...

ask a silly question..get a silly answer... (FHLH)
 
Here is what I cobbled up for 1 job, have used it for other things:


What I would change are:
1. larger thru hole (looks like your bearing might allow this)
2. chain final reduction drive with a sprocket welded to the backing plate
on the chuck, that large pulley on mine needs to be bigger, and is getting
in the way.
3. a footpedal for the on/off.
 

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I don't understand the question or more importantly the desired output of the project.
Bob

It involves welding...not carbide grinding....:D

Sorry, couldn't help myself Bob.

Valid question though. Some people use positioners to manipulate objects to where they can weld them. Perhaps they make all the welds horizontal or something that's easier for the welder to give a better weld.

In this case it seems the OP is looking for something to help him weld the circumfrence of round objects. Something that is very hard to do without a rotary.

I like the stepper motor idea.
 








 
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