Hole Depth Gauge

TLDR: Simple depth gauge for holes etc with a minimum diameter of 5mm

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This is my take on a design I first saw in 1976 during my very first term of high school metalwork. It was drawn on the 'shop blackboard by our teacher, “Digger”. His real name (and the name you used when in his presence) was “Mr Gardiner”. But to every pupil throughout the school - and quite possibly to some of his colleagues in the staff room - he was “Digger”.

Anyway Digger's design consisted of a small chunk of metal (to be cut and filed into a coathanger-shape by each student), a short length of metal rod (to be cut, cross-drilled, and a thread added by the student), a slightly larger diameter length of dowel (to be drilled, tapped, and then knurled by the student), and the final part was a plain 6" (150mm) length of 1/8th" (approx 4 mm) thin steel rod to act as the depth probe.

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