Gillette Copper-Colored Brass Caps

[TADIII]

When did Gillette move to the three-piece razor cap alloy that looks "red" instead of "yellow"?
My (admittedly small sample) observation has been that the change occurred in the '30s; later NEWs and Techs can be found with the copper-colored metal under their worn plating. I have seen yellow brass NEW caps on pre-Reissue heads, but I have never seen an Old Type copper-colored cap, only yellow.
The Gillette ownership change took place in mid-32, so was that when the cap alloy changed?
Thank you.

Tom

 

[TobyC]

You've probably narrowed it down as best as it can be. I've only seen it on New's and Tech's, and not on later Tech's.

 

[jar_]

I will have two News offered during St Sue, one with the yellow cap and the other with the red cap. So the transition was likely right about the time the New was introduced. I've never come across a yellow cap Tech.