"Lloyd E. Sponenburgh" wrote:

"Pete C." fired this volley in news:4d0be94a$0$9804
:

And remember, you *do not* need coolant for most machining operations in
aluminum.

But you need _lubrication_, or you get false edges built up on the tooling.

Not if you are using sharp tools and the correct speeds and feeds. You
can also use compressed air to blow the chips out of the way further
reducing the risk of chip welding.


All the more reason to use a polymer for the backer instead of wood.

Either will work, the MDF will be cheaper, though likely to get reused
less before being tossed, so probably a wash price wise.