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View Full Version : Proper metal cutting



SJorgensen
02-06-2004, 01:17 AM
I am gaining a lot of experience the hard way. A few weeks ago I learned that you might get away with a plunge cut with a sharp end mill in aluminum but not in steel. Ruined a $30 end mill. Now I am having a real uncomfortable time with a large amount of tiny super-sharp sliver needles. What is the best way to avoid this? I really like the curly swarf I make with my lathe but this stuff is terrible.

Any advise other than to get thicker skin or to build up calluses?

Thrud
02-06-2004, 01:33 AM
Spence
I use a vacuum to suck that up. With bigger machines and higher horsepower you can indeed get the "6's & 9's" of a proper cutting insert flying off like crazy. Not to hard with aluminum. Harder with a small machine a tougher metals. You get the same problem when using single cut burrs - they produce needle sharp swarf as well, but the double cut burrs do not - they produce more of a "dust" (Micro swarf really) that is not as much a PITA.

If you set you cuts up so that each tooth is taking about a .oo6" cut you will have less tendency to produce the slivers, so increase your feed rate and rpms and use a two flute endmill instead of a 4 flute. You can take a chip and mike it on the thick end after it has cooled, if it is under .oo6" increase the feed per tooth to get it up there. Remember too, that to get under work hardening materials you have to cut below the top .oo3" layer, so taking off .oo6" is a good rule of thumb to shoot for.

J Tiers
02-06-2004, 01:33 AM
Magnet in bag for cleanup, as someone here (Weirdscience?) sugggested.

Getting used to it, calluses, etc won't hurt. The way my hands usually are, I figure that I may be an office-working engineer, but after the revolution, I'm safe if they check hands to ID workers. Mine are uncleanably grubby at times, and usually cracked, with a swarf cut or two, etc.

Those slivers are a real pain. Take deeper cuts and get chips?

Rustybolt
02-06-2004, 01:44 AM
I'm not kidding. Invest in a really good pair of tweezers, a 10x eye loupe, and hone a stout sewing needle.

SGW
02-06-2004, 10:24 AM
I keep a shop vac handy and vacuum frequently if I'm getting the needle-sliver swarf. It also helps to set up barriers on the milling table to keep the chips from flying so far. You can buy chip shields, but I generally just prop up a couple pieces of thin sheet aluminum in the line of fire. Not the greatest, but it helps.

Forrest Addy
02-06-2004, 12:50 PM
There's more than one way to bring your work home with you and it also affects your relationship with your loved ones.

There's worse things than a mill chip in the fingers. 30 years ago, I tracked home a few long needle-like slab mill chips - nice strong ones from a block of monel.

A few days later I was rolling around on the rug before a roaring fire in a passionate embrace with my sweetie of the time when she reared up with an outcry: "A-hah!" I thought, "I AM the greatest lover."

No. Not true. She got about 1" of a 3" needle chip in the cheek of her rosy bottom. I had to pull it out with pliers. She bled for a time - alcohol and hydrogen peroxide, soothing reassurances, bandaid all were applied with care and concern. Tragically, the mood was irrevocably sundered. She went home and I slept alone that night.

lynnl
02-06-2004, 12:54 PM
Don'tcha just hate when that happens?

Cass
02-06-2004, 02:07 PM
Use coolant. The best being the black sulfur thread cutting oil which is viscous enough to cause the chips to stick together and not fly around. With a chip shield you should be able to contain things. Stiff, high torque mills don't have much problem with this. A 30 hp cut with a big multi-insert shell mill has more problems with throwing hot shrapnel. Slowing things down and increasing the feed will make bigger chips at about the same rate of material removal. A magnet in a plastic sandwich bag works good for picking up chips. Hold the magnet in your hand inside the bag. When you get a load of chips stuck to the magnet just turn the bag inside out pull the magnet away and pitch the bag of chips and oil.

JCHannum
02-06-2004, 04:34 PM
Forrest's tale of whoa reinforces the need of attention to cleanliness and housekeeping.
Another word of advice is certain other amorous procedures should be avoided after slicing jalepeno peppers.

John Stevenson
02-06-2004, 07:11 PM
Good God Forrest, My hat off to you, they pay serious money round here to achieve just that, together with the handcuffs blindfold and a wet kipper.
You need the wet kipper as proof you are not a pervert.

John S.

PS. Did you kiss it better ?

Paul Alciatore
02-06-2004, 07:18 PM
I like the magnet in the bag trick. Mostly I vacuum. And pick chips out of my fingers.

Another magnet trick I use is holding paper towel in place on the lathe or mill with small magnets. I got a pack of 50 button magnets from the crafts section at W-M and I keep them in the shop. When I use them I put them in the cormers of the paper towel and wrap about 1 1/2 layers of towel over them to keep them sort of clean. The chips fall in to the towel and it just gets wrapped up and tossed out. If any chips get on the magnet, some duct tape makes for easy clean off.

On the loved ones issue, I heard of a better one. A friend of mine did electronic hobby work at home. He was working an a project one day in the kitchen and he dropped one of the 16 pin ICs on the floor. His wife walked by barefooted and all 16 pins got stuck into her foot at once. Ouch, ouch, ouch, ...(16 times). He was in the old dog house for several days. And no, it really was a friend, not me. If I had done that there would have been reports of Italian cuss words being heard from Atlantic to Pacific.

Paul A.

BillH
02-06-2004, 07:25 PM
run a magnet on the floor of your shop, just in case you ever entertained thoughts of walking around the shop barefoot, you'll be frightened enough to never ever do it.

SJorgensen
02-06-2004, 08:57 PM
Thanks guys,
I'll apply all of the above. A magnet sounds like a great idea. I was using a shop rag and that turned out to be the worst idea. The best thing is to make a cut that doesn't result in those fine slivers. I also need to invest in a good shop cloak that won't tend to pick up swarf and that doesn't burn easily. The other day I was wearing a fleace jacket while grinding and the little sparks that would normally bounce off just melted into the fleace. Nearly ruined it.

Thanks,

Spence

wierdscience
02-06-2004, 11:09 PM
Geez Spence,one Old Navy commercial to many huh? http://bbs.homeshopmachinist.net//biggrin.gif

Magnet with a stick attached positioned near the toolbit helps,paintbrush to brush the chips away before you touch it helps too.

I had a good one once,had a pair of work boots that I nearly threw out cuase something kept sticking me in the foot and I couldn't find it,finally I did and unscrewed it,stupid corkscrew chip screwed itself into my boot sole.