Parting Tool Chatter....Ideas?

[tclaunch]

I tried using the parting tool, bought a HSS blade from McMaster Carr that said India on the blade it was a 3/32nds width I heard the moaning and groaning as soon as it hit the barrel just above the tenon where I was wanting to refit a Krieger barrel I had for a previous action a model M to fit my Borden BR.

I did find that I had set the tool up to be center off the tailstock, but had used a single wrap of solid core wire in the chuck around the barrel blank. This meant I was to low. I readjusted the tool and no difference. I kept feeding it in so slow and used Vipers Venon in a constant rate.

The one thing did amaze me was on a chip clearing I ran it away from the work, and went back in and presto, it was peeling the metal like a hot knife thru butter and finished my cut in style. I stayed at my project, and turned the tenon to diameter and faced to length, came off .240" for the recoil lug and was ready to use the parting tool aain for my relief cut of .035" for the next step threading.

It was nothing but chatter for the whole cut. I did finish my tenon, and am waiting on my floating reamer holder to arrive later this week. I will chamber, then cut the angle for the bolt nose. Any help as to why I got the chatter with the cutoff tool would be much appreciated, Tim

Edit to add, the setup on the tool for depth of cut was with a 1.250" barrel stub, just set out enouch to reach bore, and the tool post was squared off the tenon after indexing in the barrel off the outside, Tim.

 

[kendog]

First thing I would check is if the tool bit is a proper fit in the holder, and if it is sharpened correctly.

 

[tclaunch]

Slowed the RPM, went to back gear and it is like a hot knife thru butter, thanks!!

 

[kendog]

I assumed you were running a slow speed. Glad you got it worked out.
Parting is one of, if not the most, difficult jobs on the lathe. If something is not right, you will know it in a hurry!

 

[tclaunch]

A friend said run it at 65 RPM, and it dawned on me his tools are carbide. I thought to slow it down. I did take the tool out and ran the 7* end over some 400 grit paper on a flat surface as well. It was the speed because I tried the sharpened tool like I ran it before and it chattered, dropped to back gear, all troubles gone!

 

[Gundoktr]

Speed, too much, will cause chatter. I part at something like 120RPM but feed steady and use cutting fluid. If you are getting chatter and still at normal speed, increase your feed rate.

 

[kgunz11]

What does the coil of copper wire have to do with anything? Center is still center, you chuck jaws are just further away from it. Has zero to do with setting your tool height.

 

[Steve Blair]

Speed, too much, will cause chatter. I part at something like 120RPM but feed steady and use cutting fluid. If you are getting chatter and still at normal speed, increase your feed rate.

[br]
Too many RPM and insufficient feed go together and are the most common causes of parting problems.

 

[tclaunch]

Speed, too much, will cause chatter. I part at something like 120RPM but feed steady and use cutting fluid. If you are getting chatter and still at normal speed, increase your feed rate.

You are correct, I had not set the height correctly from the start.

 

[tclaunch]

I took of the tenon from a barrel Mike Davis chambered for me, as when I was attending the Nats, I asked to look inside with a friends bore scope. It was time to set it back. It is in the lathe now.

I used the same parting tool in back gear, and had zero issues. My problems were the spindle speed.

 

[DanCarey]

This is what works for ME, constant synthetic oil running over the tool, I run the lathe at 325 RPMs and feed the tool at .004 per revolution on auto feed. I set up the tool off the chuck face and its about .010 above center. Its strictly a speeds and feed issue. I have used a cut off tool at 650 and .010 feed with the same results. light feeds will chatter every time.

 

[hogpatrol]

I take my parting bits and standing them on end, push them in to a 12" or larger grinding wheel to get a radius for the chip to follow. Also make sure your tool is at a positive rake and on center or just a tad below. The problem with parting is the surface speed changes as the tool goes to an ever decreasing diameter. Every toolbit/material combo has an ideal surface speed cutting RPM. On CNC machines, the spindle speed increases as the tool moves to adjust for the decrease/increase in surface speed. Hog