Day 35, A small No. 21 Stanley miter and try square

Published on 2025-05-22 by Mark VandeWettering

This little gem is at the intersection of three things that I really like:

  • old tools bought for a song at a garage sale
  • particularly when they have a patent date or number on them
  • for some reason, I have a particular liking for squares of all kinds

This is a small Stanley No. 21 machinist miter and try square, probably around 100 years old. It has a pretty clear stamp of the Maker and patent date along the rule, despite being in pretty rough shape. I did some work at trying to clean up the rule, but as you can see in the closeup, there is some pretty rough pitting, although the numeric markings are quite good. It locks into an accurate 90 degree when tightened. I probably could do a bit more cleaning of the base, but I have at least got it roughly clean and waxed so that it operates reasonably smoothly.

Stanley No. 21

Maker's mark and patent date, No. 21 Stanley, 1-17-23

The specific innovation listed in the patent is that the blade has a slot all the way through, rather than being notched as in other designs. This allows the blade to be pivoted to any position. The patent contains the tool is:

A combined miter and try square comprising a tool stock having convergently arranged mitering and squaring edges and a blade pivotally secured in the head of the tool stock between said edges and adapted to be swing from cooperating relation with one of the said edges over to the opposite side of the head in cooperating relation with the other edge with a seat on each side of the pivotal mounting for said blade, said seats being positioned to simultanously engage one side edge of said blade to definitely establish the angular position of said blade and stock.

Yeah, what he said.

Illustration from the patent

I like this little guy for working on small boxes and stock. The 6" size is quite convenient, and fits easily in my toolbox where a larger one would be less convenient.

Happy Thursday to all.