Re: [CAD_CAM_EDM_DRO] DEEP POCKET MILLING

"Victor Cantu Jr." wrote:

> I WILL SOON BE HAVING TO MAKE A PART THAT IS 12 X 6 X 6.250 DEEP. THE PART IS ALUMINUM 70-75. ANY WAYS MY QUESTION IS IT HAS ALMOST THE ENTIRE CENTER BORED OUT, AND THE BORE GOES ALL THE WAY THROUGH. BEFORE I GET STARTED I AM HOPING SOMEBODY WILL GIVE ME SOME ADVICE ON TOOLING AND ALSO HOW YOU THINK YOU WOULD GO ABOUT DOING IT.

This isn't completely clear. Are you saying you need to bore out a hole, pehaps
5 x 5" and 12" deep? This is going to be pretty tricky to hold any accuracy on
unless you have a horizontal boring mill. A larger horizontal mill with the
arbor running all the way through the work would also work. A smaller H mill
just doesn't have the room to accomodate the setup. I don't think this is a good
candidate for a vertical mill. You could do it with a long boring bar, but the
unsupported far end will make things real difficult. Another alternative is
to do it on the lathe with a boring bar held between centers, but there would
be a lot of fixturing to do the whole thing, unless the hole is to be completely
round, not rectangular.

If I've got this wrong, and the hole is roughly 11 x 5 x 6 or 6.25" deep, that
is a bit more approachable on a vertical mill. A boring head migh be the
best way, depending on the corner radius. You could start with an ordinary
end mill, then flip the work over, or go to an extended shank end mill.

Jon