If I were building a pottery wheel, what would be the ideal situation in terms of motor specifications?

Would the motor from a belt-drive circular saw be sufficient? Is there a simple way to regulate speed reliably and safely? Thanks for your time!

Comments

[steveastrouk]

Try a washing machine motor - they are speed controllable, and they run at around 1400 RPM, driving the flywheel like Rick suggests, making it say 10X bigger than the drive shaft would give you 140 RPM, or 2 and a bit revs/second.

Steve

[Prfesser]

The motor from a belt-drive table saw will almost certainly be powerful enough. Two issues: noise, and duty cycle. Some small table saws have universal motors and they're pretty noisy, which can get kind of tiresome when doing pottery. Steve's suggestion of a washing-machine motor (or a dryer motor) is a good one.  Duty cycle should be "continuous" or the motor will overheat and quit.  Usually in the middle of a job. :)

One way to vary the speed would be to use a cone drive.  For this you need a nicely round flywheel with a smooth edge.  Cut the valve stem off an appropriate-sized bicycle inner tube and stretch the tube over the flywheel to give the wheel a rubber tire.  Make a hardwood or plastic or aluminum cone to fit the shaft of the motor.  Mount the motor so that the cone bears against the tire, and so that the motor +cone can be moved up and down to adjust the speed.

Say for example that the flywheel is 24" dia, the motor is 1800 rpm, and the cone tapers from 3/4" to 2.5" diameter.  When the tip of the cone bears against the tire, the speed will be 1800 x (3/4 / 24) = 56 rpm.  When the base of the cone is against the tire the speed will be 1800 x (2.5 / 24) = 187 rpm.  Probably too fast but you can mess about with the cone size to fix it.  Or just stick a piece of rubber tubing over the motor shaft, to give a single speed.

Good luck!

[freewheel]

The cone drive idea is pretty slick. I never would have thought of that. The cone idea reminds me of another cone-shaped gearing like is used on nicer drill presses where you set the speed by moving the belt from one wheel to a larger or smaller wheel mounted along the drive shaft.

[rickharris]

If you put a fairly heavy fly wheel on the bottom and drive that a) you will get the step down in speed you require and b) it will even out any speed fluctuation.

Have a look at the specs for several commercial potters wheels to gauge motor size - i would have though 1/4 to 1/2 Hp would do it.

[freewheel]

Indeed. The monster-sized ones that people use to center 40 lbs of clay and up (to raise planters and urns) max out around 1 hp. Most of the wheels operate at 1/2 to 1 hp. Great idea with the fly wheel!

[rsanchez20]

I have an 8000 rpm motor, 2.9 hp. Is this going to be way too much power for this project?

[orksecurity]

For whatever it isn't worth, I'm told that one of the traditional approaches to homebrewing large pottery wheels is to use an automotive differential (from a junkyard) as the base and gear train.

Beyond that, deponent knoweth not.