TOP LEFT: You can bolt the existing mount of the transmission drive case to your wooden frame. TOP RIGHT: A piece of bent angle iron or sheet metal connects the side mounts of the gearbox to the chassis. BOTTOM LEFT: Clay spins on a cast epoxy head attached to the washing machine spindle by a split-taper bushing. BOTTOM RIGHT: The finished project.
MOTHER EARTH NEWS STAFF
Few amateur potters can justify the purchase of a motorized potter's wheel. After all, the prices of economy models start at more than $200, and variable speed units will often cost well over twice that amount.
However, the "motorized" pot turners do make throwing easier, and freedom from the chore of constantly kicking a "person-powered" wheel can be a real boon for the beginner who's trying to learn to turn a lump of clay into a bowl. As a consequence, when reader Rea Williams told us about a wheel that he'd fashioned from an old washing machine, MOTHER EARTH NEWS' research staff quickly began studying how to make a pottery wheel based on that idea.
Our wringer washer potter's wheel—which was inspired by Mr. Williams' design, but turned out to be a little different from the inventor's original—proved quite a bit easier to build than we had initially imagined. As it happened, the Maytag wringer model we chose required little more than an epoxy head and a bushing, an automobile headlight dimmer switch, a hog pan, and a wooden frame in order to be pressed into its new service. And once we located a suitable washer, the conversion materials cost less than $25 ... giving us a true bargain in wheels.
A Clean Machine
Old-style wringer washers have the virtue—for a potter's purposes—of spinning at a relatively slow speed ... most run between 70 and 90 RPM. (Rea picked up an 85-RPM Speed Queen from the dump, while our scavenged Maytag clips along at 72 RPM.) The newer automatic washers, on the other hand, have much lower transmission ratios and rotate far too rapidly for potting ... so avoid them when you're searching for your recycling candidate. (We managed to buy three functioning Maytags, for between $5 and $10 apiece, by simply placing an ad in the local paper.) Furthermore, there are many different shaft and mounting bracket arrangements among the numerous brands of wringer machines. Therefore, if you choose a make other than a Maytag, you'll probably have to make a few alterations in the dimensions we've provided.
Once you've toted your retired clothes cleaner home, remove the machine's tub and disassemble the chassis so you can extract the transmission and drive motor. The leftover parts can be stowed away for future projects, while the drive components should be set on your workbench for inspection and modification.
On Maytag units, you'll need to cut back the housing around the drive spindle about 1/2" ... to provide enough engagement of the head on the spindle to prevent wobbling. (Just cut around the tube with a hacksaw, but be careful not to mar the bronze bushing which is set into the sleeve.)
Cast epoxy makes a very serviceable head for the wheel ... since it's practically unbreakable, easy to form, and provides just the right amount of adhesion for the clay. We made ours by pouring the resins into a smooth eight-inch pie pan ... but you can cast yours in any size that you feel is appropriate to the kind of work you intend to do.
Once the epoxy has hardened, find the exact center of the head and mount an H X 7/8" malleable split-taper H bushing on the underside. The screw holes will need to be drilled and tapped, and it's a good idea to set two of the fasteners from the bottom and two from the top—by countersinking them into the surface for extra strength. Then test the bushing's fit on the transmission spindle, and squeeze the split-taper in a vise until it will nestle snugly on the shaft. (As added insurance against the head's spinning on the shaft, you can fashion a locking key—which will slide into the transmission spindle and the bushing's keyways—using a piece of 3/16" steel.)
While experienced potters may not feel that a splash pan is necessary, throwing a pot can be a pretty messy experience ... especially for the novice. A suitable drip catcher can be made by cutting a 1 1/2" hole in the center of a 16 1/2"diameter hog pan. Just slip the modified container over the transmission drive housing, add a rubber grommet to prevent leaks between the pan and spindle case ... and you'll have a splash retainer that's easy to remove for cleaning.
Our Maytag transmission and drive motor are encased in a triangle of lumber, which allows the use of the original gearbox mounting holes in conjunction with a set of brackets made from angle iron. You should use either a miter box or a radial arm saw to cut the angled pieces of the chassis, but "guestimation" and some filing will get you close enough for an acceptably snug fit.
Start the framing by fitting the two long sides of the triangle to the double-width leg and the two side legs. Then line up the transmission unit between the long 2 X 6 boards—set high enough to allow the spindle shaft to reach at least three inches through the soon-to-be-added top—and bend two pieces of angle iron to form the side brackets. Once you've secured the drive assembly in its mounts, attach the third side of the triangle and bolt the rear transmission mount directly to the wood.
Now saw a top covering from a quarter sheet of 1/2" plywood, line it up very carefully, and cut a 1 1/2" hole in the board, so it will fit over the drive spindle. Slip the lid into position, drill and countersink holes for wood screws, and fasten the top to the frame rails. Finally, you can complete the chassis by fashioning a seat—to rest atop the side legs—from a suitable length of 2 X 12.
To allow for instant shut off without the need for removing one's hands from the clay work—we fashioned a foot-operated cutoff from an automobile dimmer switch and some leftover 2 X 6. The original cord from the washing machine can be wired into the switch ... though you might want to add some additional wire to provide a longer hookup.
Potters who have tried our wheel find that it works quite well and is actually comparable in performance to any single-speed commercial unit. However, a variable-speed head can be very helpful for accomplishing the different steps in the throwing process. For example, it requires a skilled hand to center the clay accurately at the relatively slow speeds at which our wheel turns. Unfortunately, we know of no practical way to modify the existing washing machine motor to provide higher speeds, so conversion to a variable-speed system would require either the substitution of a brush-type motor capable of operating at varying RPM without overheating perhaps a DC unit with a transformer or the use of a multiple ratio transmission.
Nonetheless, for the money and time invested, you'll have a hard time beating our scrounged potter's wheel, and with a little effort on your part it'll turn out some very worthwhile additions to your household crockery supply!