U-G-L-Y quartering tool

It could hardly have been less beautiful or elegant, but the Polymorph seems to have put me back in action. Indeed, it was so quick and effective, I’m hard-pressed to see why anyone would quarter drivers any other way!

Having learned that the spokes would stick to the Polymorph, I masked off the front drivers. This had the side benefit of keeping the plastic out of the spokes – they are irrelevant for quartering.

Then I boiled water to heat up the plastic and made two short snakes and two sheets slightly bigger than the wheels. The stuff has about the same working properties as melted cheese, and you have to form it quickly. However, it is easy to re-heat if you get it wrong the first time, as I did.

Then I smushed (yes, smushed) the sheets over the wheels, poking the crankpins through, and making sure the sheets were snug against them and draped around the tyres. Finally I connected the two sheets together with the snakes roughly on opposite sides of the assembly so that any stress from shrinking plastic would be equalized.

After everything had cooled, I had a bit of carving to free the wheels from their cases. I also carved the snakes so they were pointy on the outside so they would present a precise line to work with. Finally I cut the snakes and carefully wheedled the casings off the wheels.

To use it, the misaligned driver set almost snapped into the two shells. Then I simply rotated them until the carved points on the snakes lined up. I dropped some thin CA into the gap, hoping to take advantage of capillary action to pull it into the failed joint. Once that was set, I followed it up with epoxy because nobody trusts CA.

The test run worked very nicely. But, typical two steps forward one step back, I found there is a short somewhere and started disassembling before I shot any video.

Front driver free of the casings
The rear drivers, re-quartered

4 thoughts on “U-G-L-Y quartering tool

    1. Thanks John. It certainly is an interesting material. My brother made some little silicone (?) molds that he and my daughter used to create simple Polymorph castings. He dusted corn starch on for a mold release. However, compared to resin, even at its most liquid state, Polymorph is very thick – too thick for most molds. Melted cheese is a very good analogy; it solidifies harder than Parmesan, however, so it would be a difficult mold-making material.

      My local art store has another reusable material for mold making that might be better. I think it is this one: http://composimoldstore.com/. I’ve not tried it, but if you do, let us know how it turns out!

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