Finding when a Plomb Ratchet was made

[natas2000]

The ratchet is on its way, might be a fake who knows, but I got it cheap.
One side says Plomb with the 2 arrows pointing down and the side just says Made in the USA.
Very plain but I think its cool.
Any way to determine the year?
I can post a picture when I get it.

 

[natas2000]

Actually in the poor pictures its marked F-21 so like others I'm guessing it's WF-21.

 

[Mintgrun]

Alloy Artifacts says WF tools were made between 1942-1945. Here's a link to that page.

Plomb Tool Company [Appendix A]

Appendix A of an article on the Plomb Tool Company.

alloy-artifacts.org