Carrier armour manufacturer?

[rob love]

I just finished sandblasting a carrier about 2 weeks ago, and found that SDA Galt mark several times, sometimes two and three times on the same plate.

The hammer marks will be the straightening process. As well, there is a fixed number of little punch marks (usually 5 on each side armour) with a cleaned circular area around each. It is thought this is some kind of hardness testing. There are normally 4 of them in a rectangular formation on the larger portion of the side armour, and one more on the smaller portion of the side armour. I have found this to be the case with both mk1 and mk2 armour.

As well, sanding marks can be seen where factory holes were drilled for things like the smoke discharger mount or the antenna mounts. I am unsure whether these were punched before hardening or drilled before hardening.

There are about 3 pages in the design branch records re the manufacture of armour plate in Canada. If there is interest I could photograph them and post them here. I can't scan them as I don't wish to break the spine on these rather uncommon manuals.