Hello group,

I was wondering how easy Alloy 260 Brass is to machine?

My project is to take a 7/8" OD (.745" ID x .065" wall) tubing and bore the
walls to .018" wall.

Would this be hard to do, and can I get a good smooth finish? What type of
tooling (HSS, Carbide?).

How hard is it to form this material. After the wall is bored to size, I
need to put it into a fixture and form a 2 degree taper on the total length
(1.125" Lg.) and also it will flatten the bottom slightly. Will this
material stretch or crack when I put the 2 degree taper on it?

Thanks very much!

Alloy 260 is extremely nasty gummy stuff to machine.

Carbide is not needed and and probably counter productive. It needs tooling
with very high back rake and light cuts.

If all you need is an inch and an eighth of tube, email me with you're snail
mail address and I'll mail you some. I'm not sure of the alloy, it is
probably 260 or 353. 7/8" od .019 or 020 wall. It is a standard tubing in
the lamp industry.

You don't say if you are tapering it up or down, either way, it'll stretch
just fine.


Paul K. Dickman


ECQCB wrote in message ...
Hello group,

I was wondering how easy Alloy 260 Brass is to machine?

My project is to take a 7/8" OD (.745" ID x .065" wall) tubing and bore the
walls to .018" wall.

Would this be hard to do, and can I get a good smooth finish? What type of
tooling (HSS, Carbide?).

How hard is it to form this material. After the wall is bored to size, I
need to put it into a fixture and form a 2 degree taper on the total length
(1.125" Lg.) and also it will flatten the bottom slightly. Will this
material stretch or crack when I put the 2 degree taper on it?

Thanks very much!

ECQCB wrote...

I was wondering how easy Alloy 260 Brass is to machine?

It machines very nicely.

My project is to take a 7/8" OD (.745" ID x .065" wall) tubing and bore the
walls to .018" wall.

How important is the OD? If the depth isn't too great, you can produce a
0.018" wall with a good setup, but you might have an unacceptable OD
variance in the raw stock.

Would this be hard to do, and can I get a good smooth finish?

It's hard (G) to say; the difficulty will depend heavily on how long the
part is. If the length is much bigger than the diameter, it will be a
challenge. The setup needs to be rigid, and the outside will need to be
well supported. I would suggest using soft jaws, bored to fit the tube.

What type of tooling (HSS, Carbide?).

I would use HSS for a better finish.

How hard is it to form this material. After the wall is bored to size, I
need to put it into a fixture and form a 2 degree taper on the total length
(1.125" Lg.) and also it will flatten the bottom slightly. Will this
material stretch or crack when I put the 2 degree taper on it?

I seriously doubt it will crack. You'll need to experiment to find out
for sure. You *might* need to anneal the material before forming, as it
will work-harden somewhat during machining. I don't see how you can form
a taper without stretching (or compressing) the material, though.

You might also consider machining the part to the finish dimensions.

Jim

Paul K. Dickman wrote...
Alloy 260 is extremely nasty gummy stuff to machine.

Whoops! Brain cramp. I hallucinated that he was asking about 360. My bad.
260 is almost as bad as pure copper.

Sorry,

Jim

Jim Wilson wrote...
ECQCB wrote...

I was wondering how easy Alloy 260 Brass is to machine?

It machines very nicely.

Whoops! Brain cramp. I hallucinated that the OP was asking about
alloy 360. Alloy 260 is a bear to machine.

Sorry,

Jim