Saturday, February 23, 2008

Metric cheating. 12 mm is NOT 1/2 inch

Been making the benchwork for the HO train layout. Purchased some 1/2 plywood for the layout top. Cut 1/2" dadoes in the frame to accept the plywood. Damn, the fit is loose. So loose that the glue is gonna have to work overtime to take up a gap that big.
Question, what's off? The plywood or the dado set? Some measuring with a vernier caliper finds the 1/2" plywood measures only 15/32", or 1/32" shy of true, where as the dado set measures 1/2" like it should. Great. Must be plywood exported from some metric armpit, 15/32 is 12 mm pretty much dead on. Must be selling metric 12 mm plywood to the gullible Merkins and calling it 1/2" . That's only about 1/32" shy of what it should be. I've been cheated out of 7 percent of the plywood I paid for, and what's more annoying is I can't cut a 15/32" dado to get a good tight fit, my dado set only adjusts in steps of 1/16", I can do 7 /16" or 8/16" but I can't do 15/32", not with this dado set anyhow.
Things like this make me anti-metrification. It's as bad as when they changed the whiskey bottles over to metric, reduced the size and kept the price the same.

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