Meccano meets Anglepoise

I have only had time for a few small tinkerings over the past couple of weeks; these included trying to cast pewter in a way that embeds copper alloys for contrast (the idea came from Oppi Untracht's book and mostly failed, I need a means to secure the copper to the walls of the mold first); carving a design into a gesso panel using standard gravers (went very easily when the gesso was dampened); carving a discarded slab of leather-hard clay into a primitive Gothic arch; and making a very "Heath Robinson"-contraption to help when hand or machine grinding of cabs and other stones requiring a precision flat face. Well, if not precision, then at least not rounded too much. In use, the stone is attached to the base of the left-hand vertical of the jig with setter's wax or similar, the right-hand vertical is ideally screwed to a work bench or immobilised with a weight on top, and the parallelogram arrangement ensures that the lateral grinding action of one's hand is regularised to prevent rounding of the bottom face of the stone. And it works, and even better when the stone is actually on a lapidary wheel. I imagine professional lapidary wheels have a rather better jig built-in. The white blob riding on the sandpaper is actually a thermoplastic, which is a very bad idea since it is as tough as nylon and greatly impedes sanding / grinding; setter's wax worked much better, both by hand and on a flat lap. I have actually thought of what might well be a better system for hand grinding on wet-and-dry, but not got around to making it yet.

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