1144 Not Breaking Chips While Turning

superman22x · Jan 24, 2019

Hi,

I have done some searching, but didn't find many topics on this. I recently bought a chunk of 1144 round to turn, since I'd heard it machines great. The issue I have is that I can not get it to break chips, I just end up with these long strings that make quite a mess.

I am turning with a Develliere H130 3hp lathe, so nothing huge, but it is tight. The lathe came with some carbide holders and general Kennametal wnmg432 inserts, so that is what I have been using.

I have tried SFM from 200-400ish. Feed of 0.005 to 0.001. DoC from 0.01 to 0.07. With the faster feeds, I just end up with thicker stringers. It's cutting nice, and leaving a good finish, just not breaking chips. With very small DoC, around 0.01 or less it will make chips... But that seems like it will just ruin the carbide quickly. Am I in the ball park here, or just totally off on speeds/feeds?

MattiJ · Jan 24, 2019

superman22x said:
Hi,

I have done some searching, but didn't find many topics on this. I recently bought a chunk of 1144 round to turn, since I'd heard it machines great. The issue I have is that I can not get it to break chips, I just end up with these long strings that make quite a mess.

I am turning with a Develliere H130 3hp lathe, so nothing huge, but it is tight. The lathe came with some carbide holders and general Kennametal wnmg432 inserts, so that is what I have been using.

I have tried SFM from 200-400ish. Feed of 0.005 to 0.001. DoC from 0.01 to 0.07. With the faster feeds, I just end up with thicker stringers. It's cutting nice, and leaving a good finish, just not breaking chips. With very small DoC, around 0.01 or less it will make chips... But that seems like it will just ruin the carbide quickly. Am I in the ball park here, or just totally off on speeds/feeds?

Way too little feed per rev. Try to start with at least 10 times the amount what you use, ie 0.01" per rev. your DOC is closer to usable range but you should probably try something between 0.05 to 0.1"

Spruewell · Jan 24, 2019

I would start at 400 sfpm and go up from there. .05 doc and .006”/rev will leave a nice finish

partsproduction · Jan 24, 2019

Plus, how do you know it's 1144? The dirty little secret of metals vendors is that they all have their own paint codes. One company near here uses red for 304 and yellow for 303, (True story here and likely everywhere) the other vendor from the same area uses red for 303 and yellow for 304.
Also, besides that, often if someone who is careless about the success of the shop will cut off the painted end. When they do that the next time someone is looking and sees that, after they cool down a bit, they try to guess what alloy it is for in shop projects that don't require certs, they may think it looks like 1144 and paint it that color when it's really EDT 150 or something.
But normally I can narrow it down by the same method you were using, stick it in the manual lathe and watch how it machines. Even then I've made mistakes at times.

EmGo · Jan 25, 2019

superman22x said:
I have tried SFM from 200-400ish. Feed of 0.005 to 0.001. DoC from 0.01 to 0.07. With the faster feeds, I just end up with thicker stringers.

Gas it up, pooch. You aren't going to break chips until you get up around .015.

If you're running 400 sfm on a manual machine you're braver than me. The smell of burning flesh deters me from those speeds. Chips down the ear are the worst.

Mechanola · Jan 25, 2019

WN inserts are fine, next question is for holder. Do your holders have negative geometry? Negative back rake angle is advised. Then the insert should have a chip breaker face. 1144, 590 sfm and 0.008"/rev. Depth of cut is your last variable.

Mike1974 · Jan 25, 2019

EmanuelGoldstein said:
Gas it up, pooch. You aren't going to break chips until you get up around .015.

If you're running 400 sfm on a manual machine you're braver than me. The smell of burning flesh deters me from those speeds. Chips down the ear are the worst.

OUCH!

I've 'rolled' a few down my cheek trying to brush them off quick, a couple down the shirt, but in my freakin' ear... :cryin:

Mtndew · Jan 25, 2019

Your feedrate is WAYYY too slow.

HuFlungDung · Jan 25, 2019

I believe the material is not 1144. AFAIK, you can't get stringer chips.

MattiJ · Jan 25, 2019

Mike1974 said:
OUCH!

I've 'rolled' a few down my cheek trying to brush them off quick, a couple down the shirt, but in my freakin' ear...

Try sizzling hot chip inside your nose

One was enough for me, decided to install guards for the lathe.

johnoder · Jan 25, 2019

There are more aggressive feed rates - even 104 years ago - when they did not yet have stuff called carbide

I see he / she was not sitting still for stringers that day

You used the word CHUNK - does that indicate that it has a little size to it?

What you can gather from this is that lathes have been built to remove metal - quickly - for a very long time

Booze Daily · Jan 25, 2019

I'd go with a smaller radius insert if you have one. Heavy DOC. .010/.015 feed.

HuFlungDung · Jan 25, 2019

MattiJ said:
Try sizzling hot chip inside your nose 
One was enough for me, decided to install guards for the lathe.

You guys know you can buy safety helmets with a full face shield flip down visor, right? A hell of a lot more useful than any chip guard on an open machine. Plus, you can take if off when you're done roughing. The visor will also protect your neck if you button up your shirt.

DDoug · Jan 25, 2019

My "Adult Acne" is leetle "c" shaped scars..... :skep:

Finegrain · Jan 25, 2019

There is "1144", and there is "1144 Stressproof". They are quite different. 1144 Stressproof is wonderful stuff, breaks chips easily, beautiful finish. 1144 (not Stressproof) is much less wonderful.

You may have not-Stressproof 1144.

Regards.

Mike

superman22x · Jan 25, 2019

Sorry, thought I replied to this earlier, but I don't see my post now. I do not have Stressproof, I bought it on eBay advertised as 1144, but could be anything I suppose.

Sounds like feed being way too slow is the consistent answer. I will try going faster and see what happens.

By chunk, I mean this is small, it's just a 1.5" diameter chunk.

david n · Jan 25, 2019

No way in heck that it's 1144 SP..............you couldn't GET a stringy chip in the stuff if you tried...............I just finished a few parts outa 1144.............don't even have to think about chip formation. Someone on FleaBay sold you a hunk of crap........prolly some 1018.

superman22x · Jan 25, 2019

I know it's not 1144 SP, but is it possible for cold roll 1144 to be stringy?

david n · Jan 25, 2019

Stressproof is a trade name or brand name ................any 1144 should cut like butter. And yes, you can get cold finished 1144...............

superman22x · Jan 25, 2019

Ok, good to know. I emailed the seller to ask if my order got mixed up, the piece I got was larger than ordered as well. They are sending another, so I will test that and see if it is different.

Thanks for the help, everyone.

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