(no subject)

[fivemack]

I've recently been trying some woodwork. If I want a cube of wood 33 millimetres on a side, I buy a stick of wood hat has been planed down to 33 millimeters on a side with square corners, I set up a mitre saw, I make two pencil marks 33mm apart on the edge of the wood, put the wood on a flat table and extend the marks across the side of the wood using a square resting on the table. I make sure the blade is in the same position relative to the mark each time I cut. I clamp the bar of wood to the back of the saw housing in two places, and I cut twice. If I've been careful the cube is 33mm rather than 34mm.

I believe that a competent metalworker could make a metal cube 33.00 millimeters on a side, I've read about Fabry-Perot etalons which are essentially glass blocks with one dimension precisely 33.0000 millimeters. Where would I look for information at the boringly-detailed level of accuracy that I gave for woodwork of how these extra orders of accuracy are obtained?

I suppose I'm looking for information at a grade that would satisfy a six-year-old's sense of recursive questioning - yes, you measure it with a micrometer, but how did you make the micrometer and ensure it was accurate. I guess this is a one-term module taken in the first year of a mechanical engineering degree, but what's the best textbook for that course?

Comments

[fivemack.livejournal.com]

I was initially thinking of making a Menger sponge (http://en.wikipedia.org/wiki/Menger_sponge), but that turns out to be particularly difficult; at the moment I've reached a frustrating stage in making what's basically a Greek-key design (eighteen 45-degree mitre joints to have a line wander around a cube in an interesting way).

Grandad made me a burr puzzle and some 3d pentominoes when I was very small, and I'm not quite sure where they are now, which is a pity.

[randwolf.livejournal.com]

Oh, dear. Problem made for additive technology, I think.