Hard time turning copper

SIM · Mar 3, 2009

Running a pure copper job in lathe that is giving me grief.

We run a bunch of parts with no problem, then one ripps the material away instead of cutting.

Using sharp, high shear tooling where ever possible, higher Rpms, lots of coolant on ops except threading, (OD single point, ID tap) where we use Cool Tool. I'd give exact SFM, IPR and DOC but we have been up and down so much I can't remember where we are now.

Right now my biggest problem is the simplest, turning the OD. Using a CNGP 432. Thinking of grinding up a HSS tool real sharp, but that CNPG is like a razor. Bad parts are getting pricey...

Thanks for any input.

Edster · Mar 3, 2009

I use LMT Fette CCGT 32.51 and CCGT 32.52 grade LW610 to turn copper 110 which is 99.9% pure. Let me know if you don't want to run the parts we do a lot of copper turning.

fmari --MariTool- · Mar 3, 2009

Milk helps ( as coolant). I tried it on a critical job. I knew it was going to stink like crazy the next day, and it did. We used it in a sprayer. I don't know why it works but it does.

Sharp H.S.S works best. Light feeds and tons of coolant. Lots of pecking and do spring passes on everything to get a nicer finish and take off the burrs.

kustomizer · Mar 3, 2009

This may seem a bit odd, but we have made a lot of copper chips in a lathe using 2 flute garr carbide endmills. I cant them just a bit for clearance, spin it fast, feed it slow and hose the coolant to it. ID and OD it seems to work well when an insert doesn't want to.

Tonytn36 · Mar 4, 2009

Diamond tooling. I used to turn a lot of big copper plated shafts (printing cylinders). Diamond tooling will leave a great finish, but it won't break a chip in copper....long, long strings.

SIM · Mar 4, 2009

fmari --MariTool- said:
Milk helps ( as coolant). I tried it on a critical job. I knew it was going to stink like crazy the next day, and it did. We used it in a sprayer. I don't know why it works but it does.

Sharp H.S.S works best. Light feeds and tons of coolant. Lots of pecking and do spring passes on everything to get a nicer finish and take off the burrs.

Thanks everyone I will give all advice a try...definitely will try the milk on one just because I have to now. Guess I should fill the 40 gallon sump with it though...

Bellindustries · Mar 4, 2009

Ive had great luck with Kennametal TPG 321's K68 with a mechanical chip breaker, and lots of WD-40
Terry

CBlair · Mar 4, 2009

SIM

The butterfat content of the milk helps, I have heard of people using buttermilk before but I sure wouldnt suggest it myself...yuk!

Most of the time when I have seen other machines set up to run copper it seems they are using very high speeds and cutting dry with dimond tools or perhaps one of the other hard coated tools. This was on a machine to turn motor comutators down to size with very light cuts.

Charles

Edster · Mar 5, 2009

Are you guys using hershey's syrup on the taps instead of molydee? I heard it mixes with the coolant I mean milk really well. If you add some Ice cream to the sump will a shake come out of the coolant nozzels?

Here are a few pics of the tool I use.

A current order.

http://i445.photobucket.com/albums/qq173/eww_enterprise/bussbars1.jpg

A few months worth of scrap.

http://i445.photobucket.com/albums/qq173/eww_enterprise/copperscrap1.jpg

http://i445.photobucket.com/albums/qq173/eww_enterprise/copperscrap2.jpg

We make a lot of copper bussbars out of C110. I think the material is pretty easy to work with. Sharp carbide tools work good. HSS wears out to quickly. The material is soft but it's abrasive so it wears the HSS tools down quick. I also use Blaser Blasocut 2000MD coolant. The MD is metal deactivator so the coolant doesn't leach something (I think its colbalt) out of the metal and turn green. It looks like milk but it sure doesn't smell like it. Anyway if you still have trouble with the copper send the job over to us. At least you won't have to clean out the stinky milk after your done.

cmjohnson · Mar 5, 2009

I can't vouch for this, not having seen it done personally, but I was told by a friend that an old machinist he knew would use butter as a cutting lube when cutting copper.

If it's the butterfat in milk that causes milk to be a good cutting fluid for copper, then this is plausible.

CJ

bradleyk · Mar 5, 2009

You need to get rid of that CNGP...cutting edge may be sharp but it's still a negative rake tool. Go with a positive tool.
Most major manufacturers have carbide inserts made specifically for cutting aluminum that are very sharp and work well in copper. I use Sandvik TCGX 3(2.5)2-AL H10. It's a much lower cost alternative to the PCD or diamond tools. The sharper cutting action is what you need to prevent that once-in-a-while rip away of material.

Edster,
I see you're using Seco's Jetstream holder. Any issues with losing the o-ring when changing the insert?

CS223 · Mar 5, 2009

fmari --MariTool- said:
Milk helps ( as coolant). I tried it on a critical job. I knew it was going to stink like crazy the next day, and it did. We used it in a sprayer. I don't know why it works but it does.

Machinery Handbook calls for milk but I wasn't going to be the first to suggest it :reading:

spope14 · Mar 6, 2009

A company that turns cooper by the ton for plasma cutters uses canola oil by the 55 gallon drum as the coolant. I had to turn and mill copper recently for a set of candlesticks and then some signs with raised letters. I bought a bottle of canola oil after busting a couple of end mills, brushed it on, and had no problem with both turning and milling. I just had to keep on top of feeds and speeds.

The problem I faced personally using Canola was the clean-up. You have to get right on it or the canola gets sticky and becomes a real issue on any surface it has been left on. If done within a couple of days, all is good. If left for about 3 days, it becomes nasty hard and gummy and you may never get it all off the machine. I still have a few globs on some painted surfaces, and in the T-slots as well as some in a few lathe crevices. Small bits, but they will be a forever reminder.

I turned some last week, once again Canola oil and it worked well. Brush it on. Before using thr canola I sprayed WD 40 all about and it "gobbed" it up and made clean-up very easy. No canola corruption anymore

SIM · Mar 6, 2009

Bellindustries said:
Ive had great luck with Kennametal TPG 321's K68 with a mechanical chip breaker, and lots of WD-40
Terry

Thanks, I changed CNGP to a Kennametal CNMG K68 setup for alum and even though its still not the optimum choice I am getting controlled chips, some chip breaking. I swapped out the single point insert I was using and went with a high shear Carmex...so thats not ripping the threads anymore, even with plain coolant. My NPT tap, I still have to give a squirt of Tapmajic for best results, but its one op at the end so I can live with that.
Face grooving I swapped out to carbide, HSS lost its edge too quick and would snap off.

Tomorrow when no one is around I'll break out the milk and butter. If it don't work I'll butter up a roll and have a glass of milk.

Thanks.

SIM · Mar 7, 2009

Tap magic although working fine produces a nice green finish a day later, soooo I gave the milk a shot this morning. I'll be dammed if it didn't produce a better thread then the tapping fluid.

Gotto go get a stick of butter now...

SIM · Mar 7, 2009

Milk was the clear winner.

Thanks Frank, aside from working real well I have a new talking point...

dasiagud · Nov 20, 2011

facing copper on a lathe

This is my first time trying to face copper on a lathe. I have a 4" diameter,.5" disc and am trying to take a couple of thousands off. i tried vaious tooling but all I get are risges, nor a nice clean face. i also tried using various speeds. Dosen't seem to make a difference. I keep the tool and copper cool.Does anyyne know what the trick to getting a nice bright finish facing copper ? Help !

PixMan · Nov 20, 2011

Old thread revival!

FWIW, I just did facing and turning of 110 copper with negative rake tooling. Despite what's written above, I used CNGP inserts. In this case I roughed out with a Valenite CNGP432-M2 grade 9605, and finished with .010" d.o.c. and .002ipr feed rates using Valenite CNGP431-SR grade 9605.

The grade is VERY similar to Kennametal KC5010, especially in the M2 chipbreaker. Kennametal's "MP" is similar and I have some, but the Valenite M2 got the job done before I could try it. In the finishing chipbreaker, no other maker seems to have a shape like this SR, and man does it work for finishing of anything hardened, abrasive, or with copper/nickel/cobalt alloys. Weird is that I think it's one of very few inserts in a big 43x size that you can get in a .031", .016", .008", and .004" nose radius.

I ran them at over 800sfm in the 110 copper, flooding with a semi-synthetic coolant and got incredible tool life. If I recall, it was over 20 minutes of cutting time per edge. The parts I did had a 6" O.D. and a flat face right to center from a 4" O.D. x 1" long step.

Here's what that SR chipbreaker looks like, in the 431 that I used:

jdj · Nov 20, 2011

D.O.C. probably makes a difference in "ripping out" type of problems that the O.P.mentioned. Just a guess.

Jeff

scadvice · Nov 20, 2011

Ok...I have to ask...

...based on the conversation about using mike, wouldn't butter mike work better yet?

Steve

BTW- even as long as I've been around, this milk as coolant is a new one on me!! Hat's off!

Hard time turning copper

Titanium

Diamond

Titanium

Diamond

Diamond

Titanium

Cast Iron

Diamond

Diamond

Hot Rolled

Cast Iron

Cast Iron

Stainless

Titanium

Titanium

Titanium

Plastic

Diamond

Diamond

Titanium

Similar threads