Good finish when milling an end of a brass piece

cut as fast as you can using lots of household bleach.

First, Iggy; what did you do to make this jerk always add the wise a$$ comments to your queries?

I like WD-40 for brass cutting fluid. For a smooth finish on the end of an endmill you have to hone the corners to get rid of swirl marks. If you're cutting on the side of the EM, use climb milling. Turn the speed up pretty good - how's that for an exact answer? Alos make sure that thin bar is clamped as close to your vice as possible.

Karl

Altho, I have noticed in diff. situations much smoother cuts with conventional. Weird, eh?

Also, 4 flute for the finish cut, slow feed. The Q is: how lite is a finish cut? .001? .005? .010? I have noticed that there is an "optimal bite" that varies with machine, material.

You could always buff the end, as well.

Also, if you hold the piece off the side of the table in Z, you could face mill the top, for a near-mirror finish, and then chamfer the edges, if nec.

I did not do much.

I will practice today a little on my own copper bars, I do think that with the above steps, and a new endmill, it should work well.

i

Plonk. Left or Right, jerks are jerks. The question is on topic for this group. Global filter set to kill.

Bye

Wes

-- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller

Copper, I've heard milk works. My mind goes yuck though.

Wes

-- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller

Yuck. Copper is gummy, brass cuts like a dream.

Use a new endmill (no dings), 200 sfm, clamp it close to the vice.

I would rather try WD-40 first.

A little followup. I tried milling 360 brass. I picked a brand new carbide endmill for this. I milled and polished one end, and milled another without subsequent polishing.

I did this at high RPM, 3,000 or so, with a 3/8" end mill.

The result is very decent. What I learned is that after a thin cut,

0.01 inch or so, it is good to make a couple extra passes without changing positions of anything. This way, the endmill removes remainders that were not milled off on the first pass. Even the unpolished surface has a very decent visual appearance and smoothness of surface.

That's what I ended up doing, to great results.

i

Just use a nice sharp endmill, either for end milling or edge-milling. That'll get it square and to within a thou or so of dimension if that matters. With light cuts on brass, you can go about as fast as the B'Port will spin. I wouldn't bother with cutting fluid.

Then a few licks with a sharp, clean, single-cut smooth file will give a very nice finish. Lay the file on a bench and wipe the workpiece on it so you can keep it square and true. Brass responds very quickly to a file. If you don't have such a file, you should. Get single-cut bastard, second-cut and smooth files from Enco, MSC, McMaster, whatever. They're inexpensive and very handy.

From there, 20 seconds at the buffer will make it a mirror finish if that's desired.

Try a new HSS endmill, see what you think about that vs carbide for milling brass.

I have very few HSS endmills, but I will try.

i

Milk for copper.

WD-40 for aluminum.

I usually turn and mill brass dry.

Enjoy, DoN.