Back in my Great Uncle’s Old toolbox (he was a finish carpenter in the 1930’s) I found this odd circle marking / cutting device that is used in a brace.
(The tri-square in the photo is 6” long)
The arms are fully adjustable in length from roughly a 1/2” radius out to ~3” So it could mark out a circle out to about 6” in diameter. Given the design, the outer edge of the circle could never be less than ~1 1/2” in radius.
The center post (pivot) has no threads on it and is tapered, so it could fit into a small hole, but could not make the hole deeper (so it is not like a drill).
The ends of the pointed arms are sharpened so it is designed to cut when moving in a circular arc.
I did find a few of these on ebay and they were identified as leather washer cutters. I am not sure if this is accurate or not. It would make sense that it was intended to cut something thin, like leather, because it could not drill deeper on its own. What I haven’t been able to wrap my brain around is why there would be a need for leather washers that large. (who needs a 6” diameter leather washer??) And more importantly why would a finish carpenter in the 1930’s need to make leather washers on the job site?
One idea occurred to me that it may have been intended for making leather washers, but he may have re-purposed it for scribing circles on a surface (like a plaster wall) and then used a compass saw to cut the circle out. Today it could probably cut the hole in drywall with no problem, but in the 1930’s walls were plaster and lathe, which would not cut well with this tool by itself.
Anyone know what big leather washers were used for or have other ideas why this would have been in his toolbox? Thanks in advance for any help provided in working out this little puzzle.
Again anyone interested in old tools can read the rest of my look inside the old carpenter's toolbox.
-- Galootish log blog, http://www.timberframe-tools.com