Identify this tool

Factual Questions
1

My great-grandfather was a master carpenter in the late 1800s & early 1900s and had a large wooden tool chest full of tools. My sister and brother-in-law currently have the tool chest at their home in Iowa. I was visiting recently and we were going through some of the stuff. Apparently some of the old saws and planes have some value.

We came across a small object we couldn’t identify. Here is a photo. It appears to be aluminum and the pivoting arm appears to be brass. The long side of the triangle is about 3.5 inches.

Here is a close-up of the pivoting arm. It says “PAT’D.OCT.1.07”

My brother-in-law thinks something would lay across the two teeth on the right and the brass arm swung around and locked it in place.

So what do you say, Dopers? Anybody know what this is?

2

Yep, here’s the 1907 patent.

“…small and compact, so that it can be readily carried in the pocket or tool-chest, and which is capable of a quick and easy adjustment to the ordinary foot-rule or the usual straight-edge, so as to be capable in its use as a marking gage, a depth-gage, a T-square, a try-square, a miter, and similar uses.”

3

Thanks, Folly! Eight minutes, not bad! I figured someone would know how to look up a patent using just the date. Thanks again!

4

Nice. I haven’t seen one before, and I collected vintage measuring tools.

Dennis

5

This has to be one of the fastest answers I’ve ever seen on the SDMB! Well done!

6

You can still buy something very similar.

7

You won’t find aluminum tools much earlier than that, either. Industrial production of aluminum didn’t really take off until the 1890s.

8

I was wondering about that. I thought it seemed pretty old to be made of aluminum.

9

What does the underside of it look like? The patent looks like it has a bubble level under there.

10

You’re right, it does look that way in the drawings. The one we have does not have a bubble level, or even a space for one. I’m guessing it’s a later version without the built-in level.

11

After a closer look at the patent drawings, it looks like the level was detachable and simply clipped into place (ours was probably lost many years ago). Figures 5 and 6 show the level on the hypotenuse of the triangle while Figure 7 shows it on one of the legs.