On my steel tape measure, I've got the usual inch and centimetre markings, and also a diamond marking every 16 inches. Fair enough.
But my measure also has smaller black diamond markings at 19 7/32", 38 13/32", 57 19/32", 76 25/32", 115 7/32", 134 13/32", and so on. Generally every 19 3/16", but not always. There seems to be one missing at 95 31/32" and the next one skips an extra 1/16"!
I've since seen similar markings on other tape measures. Anybody got any idea what they represent?
But my measure also has smaller black diamond markings at 19 7/32", 38 13/32", 57 19/32", 76 25/32", 115 7/32", 134 13/32", and so on. Generally every 19 3/16", but not always. There seems to be one missing at 95 31/32" and the next one skips an extra 1/16"!
I've since seen similar markings on other tape measures. Anybody got any idea what they represent?