Radius gauge and reverse engineering

[tonyfoale]

Tony, a typo in the pdf´s Appendix:

¨Firstly we calculate the slope of the two lines AB and BC, then we bisect lines AB and BC with normal lines (shown in red), these will meet at the centre. The slopes of these two lines are obtained by multiplying the slopes of AB and BC by -1¨.

This holds true only for slopes of 1 or -1. Perpendicular lines have slopes that are negative reciprocals of each other.

Of course, you are correct. That was a stupid mistake.

PS. File has been fixed.