A piece of vinyl tape on either jaw should protect the coin, and then deduct the thickness of the tape from the diameter. Or if you can easily zero the caliper that would work also.
Posted 07/26/2010 9:28 pm
I have seen 6" calipers used by a dealer at a coin show, where the jaws were made of a moderately hard plastic. Such an instrument would be used in the manufacturing jewelry trade, especially for high purity gold items, which would be relatively soft. I use 4" calipers when I am faceting gemstones, but most gem faceting material I use is harder than steel, so soft jaw material in the calipers is not required.
