Breechblock pin

[DonVoigt]

Originally Posted by mrerick

The pins are hardened, are brittle and tend to snap / fracture. I had it happen a couple of times before replacing a pin with an oversized one.

Mark,
If they are brittle, then they are not hardened and drawn correctly.
There is a difference between "hard" and too hard(=brittle).

More likely what we are seeing is stress cracking emanating from a flaw or inclusion in the original material.

Rick,
I gave the drawing dimensions and tolerances in my post above.
The toggle train is designed with some "looseness", but not a lot.

Sandromxp,
If the pin was received "broken" in the replacement toggle, I'd send the whole thing back; and start over.