How Can I Reduce Parting Tool Chatter

[pineyfolks]

I just got one of these Armstrong cutoff holders and they work great on older machines with lower hp and slower spindle speeds. They really reduce the chatter.

 

[AGCB97]

See post # 32 in this thread

Another Parting off Thread

I guess I'm confused with terminology, I was thinking the blade and the part had to be exactly parallel on the face, as in no tangents. to cut straight. That would make them perpendicular.

www.hobby-machinist.com

Aaron

 

[SLK001]

With problems like this, you need to post pictures of your setup. You say your workpiece is chattering, which is a different problem from your tool chattering.

 

[benmychree]

304 is not at all pleasant to work with, 303 is the way to go.

 

[mattthemuppet2]

most people that have problems parting run the part too fast and feed too slow. Run slow (I was at 75rpm for a piece of 2.6" stainless today), feed HARD until you see nice little curls popping out of the cut and flood the cut with cutting oil (steel) or kerosene/ WD40 (alu).

I have a couple of those MGEHR parting tools, one with a molded insert and the other with a ground insert. Haven't had a whole bunch of success with them to be honest.

 

[Janderso]

I just got one of these Armstrong cutoff holders and they work great on older machines with lower hp and slower spindle speeds. They really reduce the chatter.

Did you mount this to your QCTP or the lantern style post?

 

[Janderso]

I don't have any parting issues with my lathe but I sure did in the past.
I took David's advice, This tool is incredible.

https://www.latheinserts.com/5-8-PARTING-GROOVING-TURNING-TOOL-4310000755.htm

 

[WobblyHand]

304 is not at all pleasant to work with, 303 is the way to go.

True enough. I like using 303, but 303 isn't considered food safe, and 304 is.

304 on a mini-lathe is even less pleasant to work with. I've been slowly uncovering things as I go. The gibs had loosened up, so I adjusted them. Today I found a raised ridge around the compound stud, which prevented the QCTP from fully seating on the compound. Stoned off the circular burr on the compound around the threads to allow the QCTP to bottom out on the compound. There's lots of this kind of stuff on these little lathes. Basically, even the good mini-lathes still need work. Been a frustrating day. In the second photo, if you zoom in you can see the chatter in the groove.

The parting tool holder for mini-lathe isn't particularly a great design either. Blade is only pinched in a short area, the rest of the blade is unsupported. There is a 1mm gap between the top edge and the top of the blade.

Going to make a Winky style holder. (Seen in the video earlier in the thread.) Today, I squared off a 7075 block to make a plinth. That way I can eliminate the compound as a source of movement. Plan to bolt the Winky holder to the plinth.

 

[WobblyHand]

most people that have problems parting run the part too fast and feed too slow. Run slow (I was at 75rpm for a piece of 2.6" stainless today), feed HARD until you see nice little curls popping out of the cut and flood the cut with cutting oil (steel) or kerosene/ WD40 (alu).

Towards that end, I am installing a digital tach/eBay special on my mini-lathe. At least then I will be able to make sure the SFM is appropriate for the material. Hope it shows up within a week. Estimating speed from a potentiometer position is not accurate.

 

[rabler]

Doesn’t look like that parting tool holder has any upward angle. Most of the ones I’ve seen do to provide a bit of postitive angle. Does mean that changing the stick-out means resetting the tool height.