Need a very slow motor (like 1 RPM).

[AtlantaTerry]

I have an idea for a project where I will be photographing items on a surface that rotates slowly and smoothly.

For the surface I'm thinking of starting off with my Ikea "lazy Susan" since it is fairly large and seems to rotate without any wobble. Or I could purchase from a hardware store the mechanism that makes a "lazy Susan" function then install it between a couple pieces of plywood.

But I need to be able to make the surface rotate extremely slowly. Possibly as slow a 1/4 RPM to 1 RPM. Maybe faster.

I own various power tools such as electric drills and a Dremmel. But I don't believe they work slowly enough.

In an ideal world the motor would have a dial where I could set the rotation speed. The maximum load would be only a couple pounds.

Also, how do I calculate something like gear reduction? I know if I have a motor with a small spindle that I can put something like a pulley on it then run a belt around the surface. Can't I by changing pulley sizes make the surface rotate faster or slower? We probably covered gear reduction in junior high shop class but that was way back in the '50s and I have forgotten most of it.

Where would I find a motor that would do the job? Money is an issue...

Thanks,
Terry

[Jim C.]

What you want is a DC gear motor, you can vary the speed of DC motor with the motor controller, eBay has all sorts of new and used Bodine gear motors
you'll have to get a controller ( basically a variable voltage DC power supply ) with the correct voltage for the motor.

You can also look into variable speed display turntables if you don't want to get into the nitty gritty of gear ratios,
search eBay for rotating display stand

[Bob Salomon]

Why not check out old turntables and see if one can be slowed down easily?

[Sean Mac]

Windscreen wiper motors often come with a reduction box built on. Scrapyard cheap.

Set it up to drive a piece of allthread as a "worm drive" for the slowest reduction. Let the allthread cut its mating teeth in a disc of something soft.

The reduction ratio is the ratio of the circumferences of your two pulleys. 3.142 x Radius Squared will probably ring a bell.

[Drew Wiley]

You need to look for gearmotors, with reduction gearing built into them. And no, at 25,000 RPM, a Dremel tool trying to drive a reduction gear would not be a good
idea. It would probably fry in about a hundredth of a second. Leave those things for doing root canals on meadow mice.

[Taija71A]

B&H sells 'Small' (9" Platter, supports up to 25 lb) Motorized Photography Turntables.
They come on sale quite frequently (< $100 USD).

The Rotational Speed is 1x Full rotation @ 1 to 2x RPM.

Kind regards, -Tim.

[Emmanuel BIGLER]

Hello from France

1 rpm motors are standard industrial products that you can buy on eBay!
For example those motors made in France (the speed is fixed)
http://www.ebay.com/itm/CROUZET-8234...-/111803825772

You can buy the gears separately
http://www.ebay.com/itm/1-Reducteur-...-/190375387776

So you juste have to chase on eBay close to your home and look for similar products.

[thaakre]

Why not a discoball motor?

[el french]

Surplus Center usually has a selection of AC and DC gear motors like this: http://www.surpluscenter.com/Electri...788-5-1771.axd

[Struan Gray]

Butcher a clock. Use the second hand drive for 1 RPM. Change the photo-taking rate for other speeds.