Perspectives of a Writer and Musician

Issues related to writing, publishing and playing jazz music: One man's muse.
by Al Stevens

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Location: Florida, United States

Sunday, March 22, 2009

The homebrew rotocaster is completed.

Here's a video of the device in operation. It looks just like many of the other rotocasters you see on youtube.

I made one change to the original design. The gear and pulley mechanism make the device topheavy on the vertical rotation. The designer suggests positioning the mold to balance the load. I chose instead to glue a block of wood to the other end of the outer frame.

The original design is found at this link:
Rotomold Machine

Observe in the video that rotation speeds up occasionally and then pauses briefly. This is a balance and friction problem. It almost seems to go into neutral then restart. After shooting this video, I rebalanced the load. The pauses still happen, but not nearly as often.

One clue is found in the motor's behavior if you grasp the outer frame and stop its rotation. The motor changes direction. Microwave ovens might need that feature. If your turkey bumps into the wall, you don't want the plate to stop rotating.

There is no easy way to declutch the mechanism to balance the load. I have to remove the motor from its connection to the axle. Which means I have to unscrew it from its wooden mount. That's a pain. If I ever make another one, I'll consider that requirement.

The infrequent pauses should not compromise the casting process. I've cast by doing the rotation manually. No way was I less erratic in my rotations than this machine will be.

Next step is to actually cast something and see how it works. That means I have to remake the molds. The ones I have now leak. It was bad enough getting urethane all over my clothes. I don't want it gumming up my cool new machine.

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