I'm just getting started with a small lathe and mill. I've collected a
number of scrap pieces of aluminum and steel for projects, but what do
you do to assess the metal if you don't know the specifications? For
instance, helpful advice on setting cutting speed if the subject is
unknown...subtitle this "already broke one end mill." ---thanks, Cliff

To the rest of the group. I have one name in my kill file. Seems like it
stopped this fellow's genuine good question.



--
(©¿©) An apple a day keeps the doctor away.
Two apples a day gets the doctor's OK.
Five a day makes you a fruit grower like me.

Karl Townsend

wrote in message
oups.com...
I'm just getting started with a small lathe and mill. I've collected a
number of scrap pieces of aluminum and steel for projects, but what do
you do to assess the metal if you don't know the specifications? For
instance, helpful advice on setting cutting speed if the subject is
unknown...subtitle this "already broke one end mill." ---thanks, Cliff


You need my handy-dandy "Feed/Speed Smoke Color Chart" Just match up the
smoke coming off the workpiece with the chart. $9.95 + $12.95 S&H Visa and
Mastercard accepted .

Karl Townsend wrote:

To the rest of the group. I have one name in my kill file. Seems like it
stopped this fellow's genuine good question.


I use the email addresses. Works for me.

Cheers
Trevor Jones

On Sat, 20 May 2006 13:42:28 GMT, "Tom Gardner"
wrote:


wrote in message
roups.com...
I'm just getting started with a small lathe and mill. I've collected a
number of scrap pieces of aluminum and steel for projects, but what do
you do to assess the metal if you don't know the specifications? For
instance, helpful advice on setting cutting speed if the subject is
unknown...subtitle this "already broke one end mill." ---thanks, Cliff


You need my handy-dandy "Feed/Speed Smoke Color Chart" Just match up the
smoke coming off the workpiece with the chart. $9.95 + $12.95 S&H Visa and
Mastercard accepted .

Some years ago, the author of this software most kindly gave me a
registered version, and I use it nearly every day. Ive turned a number
of my customers on to it and they love it

http://www.machinist-toolbox.com/

Mine is an older version, running on my PDA..and its handier than
thumbs.


Gunner

"If thy pride is sorely vexed when others disparage your offering, be
as lamb's wool is to cold rain and the Gore-tex of Odin's raiment
is to gull**** in the gale, for thy angst shall vex them not at
all. Yea, they shall scorn thee all the more. Rejoice in
sharing what you have to share without expectation of adoration,
knowing that sharing your treasure does not diminish your treasure
but enriches it."

- Onni 1:33

First I'd check the mystery piece with a magnet. If it's magnetic, then
check it with a sharp file. Get some samples of known steel to check
for "fileability". Get some cold rolled 1018 or A36 (hot rolled mild
steel). This is about a soft as it gets. If the mystery piece files
as easily as the 1018 or A36, then using HSS cutters, try about 100 sfm.
If it does file, but not as easy as the 1018/ A36, try about 50 sfm.
If it doesn't file at all, forget it unless you KNOW how to anneal it.
Aluminum should be obvious.
If it is non magnetic, but looks like steel, it may be stainless steel.
Slow down to about 50 sfm (with HSS tooling).
Use gentle feeds until you get the feel of the stuff.
You may be able to go 4X or more as fast with carbide, but unless you
have fairly heavy equipment, you'll have a hard time making accurate
cuts in hard stuff.

In my opinion, getting a bunch of unknown drops when you are just
starting off may not be a bargain at all, especially if you put a lot of
time into a part and then spoil it due to unruly stock.

Pete Stanaitis
---------------

wrote:

I'm just getting started with a small lathe and mill. I've collected a
number of scrap pieces of aluminum and steel for projects, but what do
you do to assess the metal if you don't know the specifications? For
instance, helpful advice on setting cutting speed if the subject is
unknown...subtitle this "already broke one end mill." ---thanks, Cliff

On 20 May 2006 04:00:00 -0700, wrote:

I'm just getting started with a small lathe and mill. I've collected a
number of scrap pieces of aluminum and steel for projects, but what do
you do to assess the metal if you don't know the specifications? For
instance, helpful advice on setting cutting speed if the subject is
unknown...subtitle this "already broke one end mill." ---thanks, Cliff

cliff
the standard way to get an idea of cutting speed is to chuck a short
piece then make a facing cut across the end.
the cutting speed will vary from zero at the centre to the surface
speed.
often one area will give you a good surface finish. that is the speed
to set your machine to run at.
if you dont get any joy set the lathe to a higher speed and try again.
if you cant get any joy when you've run out of speeds to try change
the shape of your tool. often a steel that is a bugger to cut will
perform really well with more rake and a finer cut.
sometimes you've just got to remember that it hasnt cost you anything
and turf it in the bin if you cant get a good finish.
make sure your tool is nice and sharp when you start.
Stealth Pilot