In need of a centre finder primarily for lathe work, I went to google and found this
Ames square.jpg a centre finder/ square patented by Ames in the 1800's.
There were a few false starts in making a reproduction , but it has become my go to on the workbench accurate enough for everything that I do.
20180511_171846.jpg
As a centre finder20180511_171619.jpg
As a square20180511_171742.jpg
And to draw a 45*, or to square an inside corner20180511_171641.jpg
Turns out that Ames had many patents including one for a moving staircase, the precursor of the escalator
Regards
Bill Howes
Not sure why pictures are rotated 90* countrclockwise. Suggestions