machining copper

[Al Messer]

Maybe you ought to consider sheet Lead. That is what I use in my Bench Vise when I'm holding something I don't want scrastched or marred. Works very well and is easily moulded to fit the jaws by hand pressure or a small hammer.

Using Milk as a lubricant for Copper: this was discovered when the only types of Milk available were Sweet, Skimmed, or Buttermilk.

[mike os]

cow, goat, sheep, yak, dog, seal or what?

[mike os]

Fresh, pasteurised, homogenised or UHT?

[oldstarfire]

Yes.

[jugs]

For copper
Machining - full cream milk
Tapping - double cream or goose fat.

Clean machine twice a week to reduce rancid stink

OR

use -
http://www.fuchs-europe.de/water-mis...pper_bras.html

& for tapping use roll-form taps instead of cutting taps (you get a stronger thread) but tapping hole size will be different see-

http://www.kar.ca/pdf/catalog/H4.pdf

john

[Jaakko Fagerlund]

Been machining EDM electrodes from basic copper and have just used a regular water soluble cutting oil as a cutting fluid that is in the lathe for every use. Leaves a nice and beatiful finish that shines. Surface speed has been anything from 80-300 m/min, basically everything works

If you don't use cutting fluid, the surface becomes dull and feels more like a new file with all those spikes. Copper tends to workharden easily and thus the chips will be hard when they exit the tool and this also crates lots of heat, so cutting fuid, cutting fluid, cutting fluid. Flood coolant is best.

[2ManyHobbies]

Do not use a positive rake on the tools, use a zero rake or possibly even a negative one.

[Loyd]

I machine electrolylic 98% pure copper for the cable reels that I manufacture.
These parts come cast and must be tooled on the lathe, drilled and tapped. I use tap magic with high speed steel tooling. For the tapped holes, (1/4-20 and 3/8-16) I drill .015 oversized holes. The copper for the brush rings is 3/8 thick and for the collector ring the thickness is 1 inch. I use spiral point taps. This is a production type setup and all works well.
www.weldreel.com
Loyd

[PeteF]

Hi John:

I asked that question a while back and the guys told me to use Milk as a cutting lubricant! I was having trouble drilling holes in 1/4" copper plate and the milk helped quite a bit.

I'd choose a different material for the jaws personally.

I guess you know that "milk" is the jargon expression for soluble cutting oil once mixed with water ... and not the type that comes out of a cow

[precisionmetal]

I've used half and half (yes... from the cow, not mixed soluble oil) when drilling copper. Works very well for me.

afa: machining -- a flycutter with a PCD tool and a little spritz of WD40 produces a mirror finish.

fwiw...

PM