Milling an AR Bolt Carrier

[distshooter]

Does anyone have experience milling a AR15 Bolt Carrier? I know they are pretty hard and will probably eat-up allot of tooling. Would CBN tolling be a better option than carbide? If so, does anyone have a good source for CBN tolling?

 

[rcw3]

What is it you wish to do to the carriers as that in and of itself can make a difference what type of tooling is appropriate?

Robert

 

[jscandale]

Does anyone have experience milling a AR15 Bolt Carrier? I know they are pretty hard and will probably eat-up allot of tooling. Would CBN tolling be a better option than carbide? If so, does anyone have a good source for CBN tolling?

Hi,
Just saw this post. I do a lot of work with bolt carriers and can tell you the CBN is not at all necessary. CBN is for high RC materials that are hard thoughout the entire piece which is not the case with bolt carriers. Bolt carriers are typically case hardened on the surface only for resistance to surface wear abrasion and are soft on the inside kind of like a tootsie pop. Some of the chrome ones are not even case hardened, just plated for the same effect.
You can use standard carbide regardless of what your goal is, 4 flute is best. The thing to be sure of is to limit your tool contact time when breaking through the case hardened surface and use lots of coolant and your carbide cutter will last a long time. With hard surfaces, you will make small chips, which equates to small material removal with the same tool pressure required to remove larger chips from, let's say, standard non treated 4140 steel. High pressure with little material removal means lots of heat, which is the enemy to any cutting tool. Hope that helps!

JS

 

[distshooter]

Thanks JS,

That is what I needed to know.

 

[jonbearman]

What do you need to mill the carrier for,extra lightness or what?