Correct finish for side plate?
 

What is the correct finish for pre-WWI, WWI and WWII side plates. I have heard everything from color case hardening, to straw, rust blue and hot salt blue?

Rust blue before 1937, salt blue after serial# 1500t (approximately) in 1937.

--Dwight

Is 1500t also where the straw disappears?

Is there a known reason for stopping the strawing?

Hi,

The reason was money. Salt blue is a speedier process which produces the same quality (from a user's standpoint).

Speeding up production = decreasing cost price.

Yes.

--Dwight

Rust or Belgian rust bluing is a very labor intensive and time consuming process and hot salt blue is much faster with less labor involved. Rust blue looks so much better though. So, the sideplates were always rust blue until the late 1930s. Thanks.