On 9/27/2010 3:08 PM, Rich Grise wrote:
On Mon, 27 Sep 2010 07:19:21 -0500, Karl Townsend wrote:

How bad were the chips?

I had no trouble with my mystery metal AL. Some AL is a stone bitch to
feed the chips up the drill bit, others work great. As nearly all my metal
falls in the mystery metal class, i can't tell you which grade is best.

You should feed maybe twice as fast as my small run.

Once, after hours, I found some really spiffy pieces of aluminum out in
back next to the bandsaw. I wanted to make a trinket, and the resident
machinist taught me how to use a mill - I was astonished how much metal
he could hog off that aluminum block; Previously, as a hobbyist, I had
used about a quarter the feed rate this guy was getting away with.

I once got tasked to drill a couple of 1/2" holes in a 3/16" plate of
304SS. I din't even know you _could_ drill 304SS with an ordinary
twist drill, but again, my coach(es) said, "GO FOR IT!" I really bore
down on that handle thingie that extends the quill, and the stainless
just gave way. I heard that sound that you hear when one mongo chip
is being produced, and it felt almost like the drill was pulling itself
into the work - I was through 3/16 of metal in a matter of seconds,
almost effortlessly!

So, I guess I'd have to admit, when I'm playing with metal, I should be
more aggressive with my cuts. :-)

I once saw a guy deburr a steel part with an ordinary pocket knife. Does
that dull the knife?

How can steel cut steel? Howcome the part doesn't cut the bit?

There's hard steel, and there's soft steel.
The hard steel cuts the soft steel.

--
I can see November from my front porch