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(David De Vuono) writes:

This machining thing is getting expensive. I broke End Mill number 2
and 3 of the four I bought for my combo mill\lathe today. I can
understand the first one going last weekend as it was a 1/8" end mill.
Then today I broke a 3/8" end mill. Was using it to cut through a
chunk of aluminum when the drill chuck (MT2 taper) or something like
that came loose on the taper when using the power feed from the lathe
lead screw. The end mill went crooked and snap. Guess I need to get a
proper End Mill holder and make sure it is snug more often. I ended up
using a skill saw with 40 tooth carbide blade to cut through the
aluminum, it cut like butter. Then I spent about 3 hours cutting fins
into the aluminum heat sink I am building. I was using a 1/4 End mill
and manually feeding it so it did not break. I then was cleaning up
the groves with a brand new 3/16 Ball End mill and snap. Guess I was
so used to the pressure of the 1/4 inch. Oh well, when I factor in
the cost of end mills, this heat sink is starting to get expensive.

Dave D.

I recently dug out the inside of a chunk of aluminum. It ended up
lots easier to drill a series of holes with a plain old twist drill to
remove the bulk material, then used the mill to clean up and make the
edges nice. The tool and machine were both much happier that way.

Gregm