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Cost is about $12, available many stores and places online, stationary stores, amazon, ebay. Comes in a metal box and easily stores in your car trunk or glove compartment.
Wouldn't surprise me, which is why the Architect I worked for in the late 70's insisted on the Staedtler pencils just as the OP shows. Final drafting work only, was done in Ink.From what I've read, there are a couple of the pencils that give false readings. What was theorized is that the pencils are organized by how dark they are rather than hardness, and somehow some are softer (or harder) than you'd expect.
There is another test using a ball bearing clamped between two pieces of lead. One of the pieces is dead soft and the other unknown. Unclamp them and measure the indentation of each. There's a formula using the diameter of each indent to calculate the hardness of the sample.
Fingernails?
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