Lap Testing

In an attempt to improve my faceting, I have been trying various laps and polish combinations, to see which produces the flattest facets and the sharpest facet edges. The present series of experiments was designed to test three laps under similar circumstances to see which produced the sharpest edges. I had been using tin for some time and, although I didn’t notice any major rounding of the edges as some people have claimed, it was possible to see the edge as a line of light under a 20x glass if the illumination was arranged correctly. (This is an old toolmaker’s test to see if a tool has a sharp cutting edge). I had read reports of ceramic producing “flatter facets and sharper edges” and so I obtained a ceramic lap from a US supplier. I was also kindly given a Corian lap by Roy Wikman, (,) for a trial. Corian is a rather hard polymer which is, I believe, blended with a mineral filler, (alumina I think but the DuPont site isn’t very informative in this respect). Both ceramic and Corian laps were half an inch thick, used as new, and had satin-smooth surfaces with no blemishes.

The test samples …

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