[nateman_doo]

This is a simple project for me. I want to take a rotary table which I have only used 3 times in the 5 years I have owned it and turn it into a lapping machine. It will have a ground plate on top with an adhesive sand paper disc spinning slowly and a fence to keep the parts in place.

The part I am trying to figure out is a motor. I would like it to be about the size of a stepper motor (nema 23) and just plug into the wall and start turning at a slow rpm. I do have extra stepper motors, but I don't know how to make them spin by themselves without some type of mach software. I can follow instructions too, so if someone has a way to make a stepper turn to a specific rpm (that I dont yet know) and is simple to either make, or cheaper to buy, then I am all ears.

[hoss2006]

Why be tied to a computer or spend for a special standalone stepper driver, just use a small dc motor or gear motor, plenty for cheap at surplus stores.
Hoss

[nateman_doo]

exactly my point. I don't want to have it computerized at all. I just want to put a part on it, flip a switch and the motor starts to slowly turn. i can tinker with the speed with gear ratio's, but still I need a motor that is a plug in and go.

[Potatohead908]

exactly my point. I don't want to have it computerized at all. I just want to put a part on it, flip a switch and the motor starts to slowly turn. i can tinker with the speed with gear ratio's, but still I need a motor that is a plug in and go.

What are you going to lap? If it needs to be precise then a figure 8 motion is probably better than just circular. As far as motor goes an AC motor would be the easiest I would think. There is already a good amount of gear reduction in the table. I would be worried about the AC motor RPM being too high. I think you can use a potentiometer to reduce the RPM but you loose torque, which shouldn't be an issue in your case as long as your motor is not too small.

[nateman_doo]

lapping small copper parts. AC motor is fine, but I don't want a hulking size 56C type motor, more like the size of a nema 23 motor. but AC, DC, I don't care. AC motor that takes 120V plug in the wall would be the easiest. I could use a ceiling fan controller to adjust the speed, but I just need a link to a motor of a hand held size.

[Potatohead908]

Google is your friend

[Potatohead908]

AMETEK LAMB Universal AC/DC Mtr, 1/4hp, 20, 000rpm, 120V - G0560603 at Zoro

115VAC RAPID REVERSIBLE AC MOTOR | All Electronics Corp.

China 120V 40W Small AC Gear Motors with Speed Controller - China Small Ac Gear Motors, Induction Motor 40w

I just Googled small AC motor. Choose your flavor.

[nateman_doo]

ive been googleing for days, but there SO much info there, I was trying to sort through it all. Thank you. The first 2 of those sound like they would foot the bill nicely.

[dorro1971]

What about a rear window wiper motor?...even comes complete with reduction and back and forth motion......?

[nateman_doo]

wow, no wonder I couldn't find my thread. I didn't realize it was moved. I figured a benchtop lapping machine would fall under.... well... benchtop machines right? I know its not a mill, but its on a benchtop. But whatever... I digress.

Anywhoo.... I had a moment while staring into the infinite beyond in my basement where my old X2 mill used to live. Then I realized that the X2 sized motor was exactly what I was looking for (or a bit smaller). So I bought a DC motor controller, (KBLC-19) and I am now looking at this particular motor since the X2 ($213) or even the X1 micro mill motor ($157) is too expensive:

0.5kw Air cooled spindle 1Pcs ER11 chuck CNC 500W Spindle Motor + 52mm clamps For DIY CNC 1050456B-in Machine Tool Spindle from Industry & Business on Aliexpress.com | Alibaba Group


So the motor control was $35.00, and the motor here is $80 shipped. I didn't pull the trigger yet since I wanted to see if I could find the motor itself without the clamp and ER collet so it would be cheaper, but so far my attempts have been unsuccessful.

[Eldon_Joh]

Why not use a granite countertop cut off as both the plate and the abrasive(use oil as a lubricant) simply put it on top of a turn table or something. no need to wear out a worm driven rotary table...

[nateman_doo]

I already have the rotary table. It will sit there and collect dust forever. At least I could put it to some use.

[Eldon_Joh]

i'm thinking you could direct drive the rotary table from 1800 rpm.. is it 60:1 already?

[nateman_doo]

I honestly have no idea what the ratio is.

[nateman_doo]

Some other motor choices:
http://www.amazon.com/0-19A-Speed-Sh...sin=B00EZEBTWK

300G.cm DC 12V 0.58A Brushed Electric Motor 3000RPM - Electric Fan Motors - Amazon.com

Ultrashort motor High-torque worm gear motor DC motor GW31ZY 12V 100rpm - - Amazon.com

AmpFlow E30-150 Brushed Electric Motor, 12V, 24V, or 36V DC, 5600 RPM: Amazon.com: Industrial & Scientific

8mm Dia Shaft Rectangle Permanent Planet Gear Box Motor 35rpm DC 12V | eBay

http://www.ebay.com/itm/Globe-AC-Ind...item589ba9697c

http://www.ebay.com/itm/NEW-ORIENTAL...item43d4617fe3
(although not sure about the spline shaft)

So many choices.... its hard to shop online without actually seeing something in your hand.

[nateman_doo]

i'm thinking you could direct drive the rotary table from 1800 rpm.. is it 60:1 already?

I think it is 90:1. I did 1 turn on the handle it it went about 4°, so that gave me 360 / 4 = 90

which if I am thinking right, a 1500 rpm motor divided by 90 would be turning it at 17rpm. Lapping is a slow process, but at 17rpm's is that too slow?

[Eldon_Joh]

17 rpm would probably be about right for something 3 foot diameter or larger.

[nateman_doo]

The motor should arrive today. In the meantime I began the physical construction of the other parts:

[nateman_doo]

Motor arrived. 12mm shaft, and the rotary table shaft is as well.

[nateman_doo]

Here is a test setup for the motion: