The Daimler armoured vehicles made during WW2 had a much more accurate hardness test and done with a very small ball probably only a few millimetres in diameter. Every armour plate had a small area surface ground, approx. 15mm square and the ball mark within it. This way the indentation could be accurately measured for depth. Not sure if this was Rockwell or Brinell method now, without checking.
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Richard
1943 Bedford QLD lorry - 1941 BSA WM20 m/cycle - 1943 Daimler Scout Car Mk2
Member of MVT, IMPS, MVG of NSW, KVE and AMVCS
KVE President & KVE News Editor
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