I needed to copy the positions of the holes
in the old cast brakeplate to my new brakeplate, so I first
removed a lot of material from the back of the old brakeplate
so the two plates could be clamped together tightly. Using the
old plate as a drilling template I drilled the new plate with
a slightly smaller drill size (0.5mm smaller) and finally I
reamed the holes to the exact size needed.