The Balltar

When the ball isn't on tour, it has to reside somewhere. It does the occasional stint just sitting on an available flat surface, but it is most properly displayed on it's presentation fixture; the balltar. (It rhymes with altar, in case it's not obvious.)

The balltar has already gone through several iterations, and at least one more is planned. The first balltar was a glass jar, the mouth of which was somewhat smaller than the ball.

The current balltar has the notable feature of spinning the ball about an axis perpindicular to the surface on which it is sitting. It was made from an AC motor which was pulled from an 8 track player. The legs are two pieces of coat hanger wire, which were bent appropriately and hot-melt glued to the bottom of the motor. Feet were formed on the ends of the legs with more glue. The wiring and the starting capacitor were glued to the side. The disc, upon which the ball sits, was formed on the pulley with (you guessed it) more glue as the motor spun.

I have 4 versions of an animated GIF image of the ball on the balltar; spinning up from a dead stop. (Reload if you missed it.) I made 4, because I discovered that the 9 frame animation, even at 1/2 size (relative to the original 640x480 images) and only changing the non-static rectangle of the image, is over 200KB in size. That is a bit large. So, I put it to you to chose one of the images linked to below to replace the arbitrarily chosen one at the top of this page. Once you've made your decision, follow the Feedback link in the navigation bar and let me know what it is.

The fact that the ball can, in fact, spin on the balltar is a testament to its roundness. It also emphasizes the fact that the ball is not perfectly uniform in terms of surface curvature and distribution of mass. As the ball approaches normal speed, it usually needs a little help to keep it from flying off in a random direction. However, once it has gotten up to speed, it is actually quite remarkable how little vibration there is, considering that it is handmade, as massive as it is, and spinning rather quickly. I'm guessing that the motor's speed is probably 1800 revolutions per minute. It does appear to be synchronous with the power frequency, judging from null beat which is visible under flourescent lights.

Occasionally, somebody comes by and tries to pick the ball up while it is spinning. Of course, that proves to be a mistake. 8)

I mentioned above that another iteration is planned for the balltar. Actually, it is an augmentation of this one. Someday, I'll get a piece of red or blue velvet or other suitable fabric. I'll build a wire frame which covers the motor and does not interfere with its operation. Then, the fabric will be draped over the frame and attached to it.


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