New lathe trouble

E

Endeavor1

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I’ve always had trouble getting a good finish. I just got a new lathe and hoped that the trouble would go away. I had an old grizzly that I inherited but just bought a PM 1440GT. I’m still getting slight chatter. I’ve tried new HSS inserts, Aurther R Warner. I’ve tried every speed and feed combo that I can. Nothing seems to make it all go away. The best cut comes from manual feed as slow as I can. The slowest feed on the machine is .0028. I’ve tried carbide but that has been worse. The material that I’m working on is stainless and cold rolled steel. These are giving me about the same results.

thank you for
 
Tools like to cut , not rub . Not enough information here to make recomendations . Got pics of set-up and tooling ?

Roughing at .010 and finishing at .005 is a general starting point .
 
.0028" is plenty fine enough
have you tried tools with a nose radius or pointed tools?
what is your spindle speed?
some cold rolled steels look like crap no matter how you turn them
304 stainless will look like crap too if you don't have a deep enough doc, it is not friendly at all
 
Let er eat. Feeds and speeds are fine but depth of cut is important. I have had trouble taking light cuts in some material. Get just ok finish. But on my "roughing cuts" I get mirrorish finish. It will make you good at judging tool deflection and hitting your measurement with a bigger cut rather than sneaking up on it with 10 little cuts.

By chance did you move anything over from the old lathe to the new one, like the tool post?
 
The stainless is 416 R. I’ve tried a crew different shaped tools. Nothing that was extremely pointed. Spindle speeds from 50-280 rpm. I’ve also tried several feed rates.
I’ve tried depth of cut from .001 to .050. The finish is slightly better with a shallow cut.
The finish is very similar on both materials.
 
Endeavor1 said:
The stainless is 416 R. I’ve tried a crew different shaped tools. Nothing that was extremely pointed. Spindle speeds from 50-280 rpm. I’ve also tried several feed rates.
I’ve tried depth of cut from .001 to .050. The finish is slightly better with a shallow cut.
The finish is very similar on both materials.
Click to expand...
What diameter of work? Your speed seems low to me unless you are turning something pretty large.
 
Sounds like your low on the speed side. Bump it up to at least 600rpm and try that, then star reducing.
I turn mostly between 300-600 rpm, threading around 90-100, parting 200
 
This goes all the way to what kinda floor it's on.
 
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