Which red metal?

[steele]

First time starting a thread-bear w/ me. I have some experience w/ free machining brass, aluminum bronze, cast bearing bronze, & pure copper. Looking for input from someone w/ even broader experience. Finished piece will be exposed to ambient, outside conditions. Prefer to minimize finishing operations such as plating, painting, etc. to keep costs down & reduce evidence of scratches when in service. Prefer not to use free machining brass since it is too bright when new & too dull when old. Also looking for a more copper color. Bearing bronze is pretty yellow & also would prefer wrought, not cast material. SO, preferring not to use 110 or 101 copper due to machinabilty I was wondering what Beryllium Copper machines like & how it looks when it ages? The finished piece will fit inside a 1x1x4 inch volume. If the product is accepted we should be looking @ 5K to 20K pcs./yr. Any other suggestions for common brasses, bronzes, or copper alloys?

[Geof]

It is a bit difficult to give an opinion without knowing the function of the part, but it is possible to say you have something of a contradiction wanting to keep costs down and then thinking about using Beryllium Copper. Which is horrible to machine and creates toxic Beryllium dust so it may not be a good choice.

What about an aluminum alloy, hard anodized and colored bronze? The coloring is stable, hard coat is quite abrasion resistant and it is probably close to the same environmental resistance for outside exposure.

[MazakMikeO]

Yes Beryillium Copper does age with a darkish copper colour, but as Geof says, it can be a bugger to machine and does produce the toxic dust. I am speaking from a milling point of view by the way.

[steele]

Thank you for the responses. I thought the beryllium would be such a small component that it wouldn't be a hazard. CA110 copper is tough, the beryllium alloy sounds much worse. I don't think I'm @ liberty to give too much away. It's a consumer item w/ "magical" properties (think like copper bracelets to fight off the arthritis). It's a relatively high value item we would like to have take a beating & still look good. Anodized aluminum scratches too easily & is not "magical" or dense enough either. Looks like I'm down to naval brass (bronze) or pure copper if I want to go w/ a common wrought material. The Machinery's Handbook has some suggestions for coloring copper alloys. They sound like a pain-would probably impart too much "magic" & destroy the world or at least my workshop. Maybe I'll talk to a plater & see what they have to say unless that gives you some other ideas. The parts will be milled all over in a 5-axis CNC machining center w/ flood coolant. I remember many years ago wrecking my coolant w/ a yellow metal; probably was bearing bronze; don't want to repeat.

[Geof]

Oh great!!! You want to put Beryllium Copper Magic Bracelets around customers wrists. Do you supply bottles of Snake Oil at the same time. I retract my suggestions; I don't want it to be known I gave advice to such a venture.

[MazakMikeO]

Beryllium copper will turn your coolant green.

[steele]

Goef-Please note I used the word "like" a bracelet; I never said it was to be worn or even frequently touched. Thank you for your input-I don't think you're liable for advice posted on a forum. I am very familiar w/ the hazards of Beryllium but, as mentioned, I had no idea of its hazards in alloy form. After all, we alloy w/ lead, arsenic & all kinds of other nasties in metals that don't hurt us. Like chromium in stainless which you probably stick in your mount many times a day.

MazakMike-thank you.

I have an e-mail from the customer questioning lead (he's in the EU which is all worried about Pb), we two will talk later. Things are looking more like copper. I have machined a little OFHC (CDA101 annealed) which was a life times worth. The Machinery's Handbook gives most of the purer coppers a machinability rating of 20 and Tellurium copper a rating of 75. I'll check some other sources but do you all have any first hand experience to confirm machinability since I have never machined Tellurium alloy. Do you know of any hazards of machining or handling Tellurium alloy? I take it this stuff was designed for machinability?

[ImanCarrot]

I used the Copper Development Agency as a source of information on Beryllium Copper and OFHC ages ago- they were dead informative.

www.copper.org