View Full Version : Opinion Wanted

12-22-2006, 04:26 AM

I HAVE to motorized my rotary table. The stuff I am making requires lots of turning. Not for indexing, just making circles etc.

CHEAP , $100.00 or so.
variable speed
strong to run a 1/2" rougher EM on an 18" diameter circle with a .100" cut through 1"thick Al. Some 1/4" steel too.
No computer control, don't need that.

I can figure out how to mount a motor, easily. Plan on timing belts and pullies, I have them here for telescopes. Motor will be geared at least 2:1

12 volts/24 volts DC ? 115 AC ?

Where to get something ? I looked at the usual surplus places, but I get torn between AC and DC. Not much experience in this app. of a motor....

If someone has something laying on a shelf, I have a new 2 HP motor I can trade too. IIRC, it's a Dayton.


12-22-2006, 04:51 AM
My hack solution:


12-22-2006, 05:30 AM
1/2 in electric drill (the kind with a mounting collar near chuck) Cheap, variable speed, and reversible. An angle drive attachment or timing belt type drive, or even a worm drive for more reduction. to keep it kind of compact. A cheap DC type drive ..........

Your Old Dog
12-22-2006, 06:20 AM
I would use a DC motor as it's easier to reverse. I'm inclined to think some electric drills not only have the power to do it but are variable speed and reversing negating the need for gearing. I would breadboard the setup and then design the mounting plate to accomodate the breadboard.

If you're looking sell off the 2hp motor could you let me know it's nema type, rpm and voltage. That's the one piece I need to build my 2x72" belt grinder.

Weston Bye
12-22-2006, 10:32 AM
Check out the DC motors used in automotive window regulators (power windows) and seat positioners. They come with an integral worm gear and are quite powerful.

see here:

12-22-2006, 11:20 AM
It don't really matter if it's AC or DC, as long as it has enough torque to turn the shaft at the load you want. I would look for a motor/reduction gear assembly and link it to the table with sprockets and chain. I think brush type motors are best for speed control and good torque at low speeds.

12-22-2006, 11:40 AM
Check the archives. Evan gave us a schematic for a ciruit to use with windshield wiper motors. W/W motors are @ 20.00 at American Science and surplus.

12-23-2006, 02:53 AM
Thanks for the input.
That ebay store, richards foundry, has a motor and controller, ready to plug in, for 149 plus shipping. I think it was 1/2 hp, variable sped, 110 AC, likely a treadmill motor. Much bigger than I had wanted, but I am not too good at sparky stuff....and this will work when I put pulleys on there.
The WW motor is a good idea, I dunno how to vary the speed though. I have to get it slowed down in the steel and reasonably fast in the Al. I like the idea of a $15.00 solution though.

Saw Evans schematic, over my head, as usual.

YOD, The motor is a warranty replacement for my mill/drill. Never used. 1750rpm, 2 hp, 110/220, farm duty, big heavy sucker, from Grainger. I can get the NEMA frame etc. if you want. Might be too big for a sander ? It's a backup for the milling machine's motor, which is a Marathon now and has not given me a lick of trouble. Might as well get it out of the shop if you can use it. It was ~$250 IIRC when I bought the first one.


12-23-2006, 11:35 AM
Lenord, I have used the following 12/24 volt controller with great success. I used it to put both a power leadsvrew and crossfeed on my smithy. The motors I used are kind of similar to ww motors (but at 24 volts), and--with a 3:1 reduction--I can throttle them down to about 15rpm with usable torque. Usual disclaimers apply. Sidegrinder

http://cgi.ebay.com/New-Electronic-DC-Motor-Speed-Control-Controller-15-Amp_W0QQitemZ170062533726QQihZ007QQcategoryZ71393Q QrdZ1QQcmdZViewItem

12-23-2006, 01:21 PM

Oh wow, thanks for posting that link. Precisely what I was looking for ! You saved me a bunch of loot !


Paul Alciatore
12-23-2006, 04:05 PM
Just a thought. Right now you may only be interested in milling a circle, but in the future you will certainly need indexing. I would do this with a stepper and a simple circuit to drive it forward and reverse, perhaps at different rates. Later, if you want to use it for indexing, you only need change the control electronics.

My table has a 90:1 worm so one revolution of the handle gives 4 degrees of travel. A 200 step stepper would have 90 steps per degree or 2/3 of a minute per step. If you want finer resolution gear it down. 2:1 gearing would privide 20 second resolution or 4:1 would provide 10 second resolution. I doubt that your or my worm gear is that accurate.

12-23-2006, 09:04 PM

Oh wow, thanks for posting that link. Precisely what I was looking for ! You saved me a bunch of loot !



Looking at the listing, that needs a pretty beefy DC power supply doesn't it?

12-23-2006, 09:33 PM
Yes, it will take a power supply.

I have a few of those floating around too :)

Looks like I may get out bid though....


12-24-2006, 12:49 AM
Please check your messages on this BBS.


12-24-2006, 02:46 AM
Stop bidding...You can buy 2 of these controllers from the distributor for $39.99+shipping. Here is a link to thier site, it is part MX-033 under assembled electronic modules. I am using a 24 dc 4amp power supply and it is more than adequate. I've had this setup running for 2.5yrs without a hiccup. Sidegrinder


12-24-2006, 11:35 AM

Thanks for not letting me make an even bigger fool out of myself ! Found the part at the site you linked me to. They have lots of other kewl stuff too !


12-25-2006, 09:49 PM

I was outbid on E-bay, thankfully.

Ordered 2 controllers and 2 motors as you suggested. Will send a pic here of the install.

Thanks for the info !

01-27-2007, 06:10 PM
It isn't pretty. It lacks a high speed, I had to gear it 6:1. The motor gets hot after an hour. It did cut a 11.5" curcle in 3/4" steel plate with a 1/2" rougher. At $100.00 and I have 2 motors and 2 controllers...It will do for now.




01-28-2007, 03:42 PM
Thats a really neat setup!

01-28-2007, 06:55 PM
Next should be a shop vac.:D

01-28-2007, 08:05 PM
My friend Alwyn constantly uses his rotary table for hour after hour, day after day...on a car wiper motor connected via loose belt .. ...this is driven off a charger ...that has high, low, medium.

if something goes wrong the belt will slip.

can get pictures if your interested, doesn't look as slick as leonards....but is cheap ...and does the job.

all the best.mark

01-29-2007, 05:07 AM
Thanks for the follow-up Leonard--Glad it worked out for you! Sidegrinder.