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Saturday, November 27, 2010

Bonhop Loom

When my wife's grandmother passed away not too long ago, they found an old toy loom at her place while tending to her estate. It had belonged to my wife's aunt. It was made by a company called Paul Bonhop Inc. in New York. It was mostly in good shape, but had a couple of busted comb-shaped plastic pieces on it. One is a heddle piece, and one is a beater comb. You can find the manual here. It looks like Bonhop made a couple of different models of this sort of loom, as you can see in this other blog entry .

To make replacement pieces, I drew the broken pieces up in a solid modeling program. Since these pieces were amongst the most complicated pieces of the whole assembly, I modeled the rest of the assembly on a whim. For those of you who know about solid modeling, look for the Alibre Design format files here and the step format model here. A 3d PDF for the loom is found here. (Note: use these files at your own risk, there may be small mistakes in them.) All the pieces except the nails and screws are there in the model, if someone wanted to make their own from scratch.

I took some ABS sheet to Club Workshop to cut on their Epilog Laser cutting/etching machine to replace the broken parts. For the most part this worked reasonably well. 1/16" thick black ABS cut the best, and was used for the heddle piece. It did warp slightly under the heat, but the detail was well preserved. For the beater, I used white 1/8" thick ABS. This was harder to cut well, and required multiple passes with the 60 watt laser. It warped noticeably, and left behind black soot marks on the plastic that are very hard to remove. Nevertheless, I got useable parts out. I tried cutting the Beater from some scrap 1/8" acrylic lying around, but the comb tines on it were so thin that the brittle acrylic simply cracked and had teeth fall off. The ABS piece will simply bend under reasonable force, and then return to shape when no longer pushed. ABS is much tougher, even though it is a bit of a pain to use with the Epilog. I also confirmed for myself one thing my fellow makers at club workshop had warned me about: ABS really smells bad after being cut with the laser, and takes a long time to lose the odor.

Thanks to Derek, who showed me how to set my line weights in an Alibre Design drawing layer to less than 0.03 so that the laser print driver will interpret these outlines as a cut instead of a raster etch.

Anyway, the loom is working again now. Some lucky kid (or perhaps even an adult) can now make some textile with it.

Posted by Kurt at 7:36 PM
Edited on: Saturday, November 27, 2010 9:02 PM
Categories: Maker