A question about steel rules.

Is your post tongue in cheek? Shrink rules are used by patternmakers to make foundry patterns to allow for the shrinkage of the metal after pouring. They are made in many ratios of shrinkage, called out in fractions of an inch per foot of length.

Shrink rules were also used in making thermo-forming dies for vacuum and pressure forming sheet plastics.
 
While digging around the dark recesses of my seldom used tool stash, I ran across an unusual Starrett rule. It reads in 10ths 12ths 14ths! and 16ths. None of my colleagues remember seeing one before, and I'm curious as to its purpose. I figure the 12ths may be an architectural standard, but what about the 14ths?
Any insight will be appreciated
Dean
Hi, I first thought it was a scale ruler,,,,,,,,but no
My best guess is; it just gives the user the option to split an inch into different divisions.
Cheers
 
I have one 12"long with the same graduations. I use it for sheet metal bending alliances. I have to use an eye magnifier.:(
 
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