Question Concerning Proto Los Angeles Semi Finished Adjustables

[Straightgrain]

I have two semi finished adjustables (704-S & 706-S) with a black finish & two (704-S & 706-S) with a bare metal finish. The two with a black finish are from 1956 (4") & 1951 (6") and the two with bare metal finish are both from 1950.

According to a catalog from 1954 (p 17) it states "..full-finish wrenches are highly polished and then chrome plated" whereas the "semi-finish wrenches have polished heads." No mention is made of the black finish.

Neither of the two with bare metal show any indication they were black at one time. Was the black finish an option, or did my wrenches originally have a black finish that was somehow removed?

 

[twertsy]

The black was offered to industry. That is just about the time Plomb started turning their focus toward the industrial market, but still had a general consumer presence. On dating those adjustables................while it's thought those JPD 3 character stamps are date codes, it hasn't been proven absolutely. Moreover, how to read/interpret them is also a matter of debate.