It's a sweet gauge, I sometimes regret not keeping it, but you are putting it to good use...
I figured that since it was built in the "good ol days" when made in the USA meant quality, it would be better than what you can buy today (chinese crap...)... I can't believe that I found it...
My great grandpa started a tool and die business in his garage back in the day. In WWII, he got enough business to move to a small shop, which I believe was real close to where that gauge was made. My grandpa and uncle ran the shop after great grandpa died, but my uncle and grandma closed it down in the 90's.