Interesting thread over on The Home Shop Machinist describing the use of H.J. Watts’ 1918 US patent 1,241,176 drill, based on the Reuleaux triangle (Wikipedia), for drilling a (mostly) square hole.
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Interesting thread over on The Home Shop Machinist describing the use of H.J. Watts’ 1918 US patent 1,241,176 drill, based on the Reuleaux triangle (Wikipedia), for drilling a (mostly) square hole.
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