Machining 416

[mr fixit]

I know some here have used some 416ss, and would like to know what it is like to machine and use for baffles. I'm considering 416 baffles for a 9mm PCC build that might also see both sub and super 300Blkout. What I have found is in the annealed state. Just wondering what I am getting into.

[T-Rex]

I've never made baffles from it, but have used barrel cutoffs for thread protectors and brakes. Cuts great. You should know your machine so push it till you can't

[Capt. Link.]

I heat 416 to a cherry red to stave off rust from forming.They also can be hardened with relative ease.Standard HSS or cobalt tooling and brush on cutting oil is all that is needed to machine.

[ECCO Machine]

416 machines easily, but not very cleanly if you don't use very sharp cutters. Gear oil will further aid in machining and tool life.

The stuff is soft in the annealed state and highly magnetic, so when you go to do your surface finish, be conscious of the fact that small chips will stick to the work piece and gall it under your files, stones & sand paper if you don't take steps to mitigate that.

416 machines much cleaner in the tempered state, but is obviously much more difficult to work with that way. Parts needing high quality finishes and precise dimensions should be rough machined in the annealed state, hardened and tempered and then hard turned/machined to final dimensions.

Small, thin cross section pieces can be hardened with a torch by color if you don't need exact mechanical properties. Tempering can be done in your home oven at highest normal setting (don't use clean cycle, 416 develops undesirable properties when tempered between 800-1100°F)

Ultimately, while a little cheaper and easier to machine than 17-4, I think you'll find 416 less desirable to work with for these purposes. 17-4 still machines pretty freely, is much easier to get a good surface finish on, is easier to heat treat, and is about twice as strong in H900 condition as tempered 416.