Marbles blades were mostly outsourced for grinding, etc.

I do have a few Marbles blades that their primary grinder ended up when they [bleep] on their suppliers and went overseas.
Most all the blades I have were out of their 'Proprietary" 52100B.
It is a good steel, but likes to pit and rust.
The blades I have are sterile as they never made it to Marbles for final assembly.

"The significant problems we face cannot be solved at the same level of thinking we were at when we created them."
Albert Einstein

At Khe Sanh a sign read "For those who fight for it, life has a flavor the protected never knew".