Milling cast aluminum

Newbie here, first post… So my question is, do i need any special bit to mill a cast aluminum plate from an amunition reloading machine a friend of mine has. It’s current thickness is 1.060 inches and he needs it down to .099 inches.

I’m not sure of the exact kind of aluminum and I don’t even know if cast aluminum is any different than say 6061 sheet aluminum or whatever. Like I said, total newb here… Any advice would be very welcome. Thank you.

Also fyi, I’m running a Shapeoko3 xxl with the Dewalt router.

Casting is a process, 6061 is the number of a particular alloy. There’s a bit of discussion on this at:

I being cast ought to make it easier to mill than if it were a forged / tempered sheet, but it being cast means that it may be made up of an alloy which is difficult to machine.

A carbide endmill ought to work fine if it can be machined easily. If it’s a soft, gummy alloy which is difficult to machine, coolant and/or a suitable endmill may help.

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  1. Buy some ZrN Coated end mills (Bits?)

  2. Advice: Buy a Makita RT0700 Router (runs at 10k, so it produces less heat)

  3. Trust me.


Thank you for all this info! Much appreciated

Rich, re those coated end mills, one, two or three flutes?

Three (3) or as my BIL says, tree flute…

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Cast aluminum is usually 356, can be porous, not too gummy and usually small chips. HS 2 flute, TiN coat is OK. Avoid high spindle rpm & heavy feed.


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