How To Date Starrett Protractor Head

[DieCastElectrician]

 

[leg17]

Look carefully along the bottom edge on both sides.
Early ones had the patent date marked (1879 or 1880).
The "checked" on the fill part looks pretty early.

 

[DieCastElectrician]

It Says "Pat Aug 7 1883 on one side and the other side has 597

 

[leg17]

Likely made prior to 1900.
The level looks a little 'primitive' also.
It was an add-on available separately.
Nice find.

 

[DieCastElectrician]

Thanks For Your Help

 

[RTM]

As leg17 implied, 17 years after a patent date is the high end for how old it can be. Used to be that was as long as it was protected. Could obviously have been made the year patented, or 17 years later, using only that guideline.

 

[AreBeeBee]

Does anyone have date info for the "checkered" pattern on Starrett squares (combo & double)? That pattern seems to have begun in the late 19th century and continued through WW2 until some date, when the company switched to the crackle and smooth finishes, respectively, for the cast iron and hardened steel heads.