...these little magneto/ignition wrenches are 3 1/2" long.
Mintgrun, your 3-piece magneto wrench set was made by Indestro.
That is a really sweet set, Tom! Nice ID, 4.c!
I like how prominent the knurled thumbnut is. Say what you want about Indestro, when they had an idea, they stuck with it. They looked at ignition wrenches, pretty much just like these....
...and thought, '
Gee, wouldn't it be better if they were kept nice and neatly altogether, so they don't get lost,' and applied the same principle that they used for Auto-Kit type combination wrench sets, with the little bulge in the middle for the screw and nut.
Later on some genius figured out you could simply stamp sizes on the wrenches and they'd fit all kinds of stuff.
I've posted these two catalog excerpts before.

Pic 1 is from a c. 1930's Bonney. Pic 2 is from a c. 1940's New Britain. When looked at together, though, they tell the story of the evolution of ignition wrenches and ignition wrench set production.
From wrenches with individualized and specialized shapes and service openings tailored to specific brand ignition systems (i.e., magnetoes, magdynos, generators, etc), to standardized wrenches (miniature DOE) with standardized angles (15* x 60*, sometimes 75*) and openings (15/64" through 1/2") that fit all the various ignition systems.
I especially admire New Britain for that table, because you will NOT find the opening sizes in early catalogs and you will NOT find the system correlations in the ignition wrench pages of
any other mfgr's catalogs, just the opening sizes. It's actually very helpful and informative.