Parting Practice Chatter

I just read above, "the advantage of using power feed when parting". It may be a good/practical idea for the production shop with proper machines and with coolant flooding and all. BUT, I would strongly disagree with the use of powerfeed parting in the typical HM shop with light duty machines and the acid brush cutting oil applicator technique or equivalent. Chip clogging and dozens of other bad things will happen before you could turn off the feed and you will have disastrous consequences. You could easily break your lathe and or hurt yourself. Please be safe and love your machines in your HM…Dave.
 
Like you I've been having parting problems.
I'm convinced that flex is the major cause, I can see the whole tool post flex in when the blade catches.
By placing a finger tip on the line between the two parts of the cross slide and the two parts of the compound slide whilst parting you can feel the two parts vibrating as they flex against their gibbs.
I tightened mine up really tight, locking the compound and making the cross slide as tight as I could but still move it and the chatter reduced.
I also made a solid block for the compound to mount to, that also improved the process.
I firmly believe the compound is a major component of the previous mentioned flexing.
My next improvement will be a solid block mounted at the rear of the cross slide with the parting tool held upside down in the hope that will totally eliminate all the chatter.
 
Hello,

i thought i would throw this in incase its helpfull.

it might be worth useing the solid toolpost mounted on the cross slide style of cut off tool holder as i have seen the compound slide flex you have mentioned with the 9x20.

Stuart
 
anyone have a set pf plans for one of these to fit the 9x20?
Feeling too lazy to draw my own:whistle:
 
Ok. I have not read any previous responses yet, but wanted to put a few first thoughts down.

1- there is going to be more pressure on the cutting tool, and your setup, cutting steel than aluminum. So- IF your cutting tool is precisely, EXACTLY level to the center of your workpiece, you may need to make account for some flex in your setup and be a TINY bit above center with your cutter.

2- once you have chatter on a part, the previous chatter marks will help maintain te chatter. I like higher speed parting operations like yours, but to remove those chatter marks, you might have to go slower and deeper for a turn or two to get below those chatter marks.


Bernie
 
Glad to hear you've made real progress with that Jim, I went through the same thing with my flexy Atlas compound.

stupoty said:
Hello,

i thought i would throw this in incase its helpfull.

it might be worth useing the solid toolpost mounted on the cross slide style of cut off tool holder as i have seen the compound slide flex you have mentioned with the 9x20.

Stuart
Click to expand...

Indeed... I just posted this this to show the difference http://www.hobby-machinist.com/show...g-off-with-my-Atlas-video?p=267693#post267693

Bernard
 
Last edited:
I posted this the other day on another thread, thinking I was in my own parting practice thread, so here it is again. Sorry for the dupe...


Video with terrible voice over soundtrack.


this is some video I shot today of my parting practice. It is better than a few days ago when I started. Sorry about the voice over sound quality and volume.


i still get the blade stuck in the video but the vibration and chatter are much better that before I made the aluminum block to replace the stock compound.


the material is 1018 CR AND 1" or maybe 7/8". The first few cuts are 350RPM and the last one or two are at 415rpm.


im planning to build a second compound mount that will pivot and make the foot of it as large as possible and still fit on top of the cross slide.


http://youtu.be/i8Dp3xbi-z0


jim
 
I watched Tom Liptons video about goose neck spring tool holders and it sent me searching the web.

why if this seems so logical, does it seem like no body sells or uses this item? It makes perfect sense and I will try to make something so I can try it.

Here is a link to the video...

http://youtu.be/KETVR9qtEmY

Jim
 
RVJimD said:
I posted this the other day on another thread, thinking I was in my own parting practice thread, so here it is again. Sorry for the dupe...

jim
Click to expand...

No worries Jim, I don't think you can completely delete posts on here but to keep thing tidy in the Atlas thread, maybe you could edit it to say 'post deleted' or ask the mods to delete it.

Bernard
 
image.jpg Update on parting...

It has finally warmed up here in Iowa so I have been doing a few little projects in the shop. One was a simple little screw jack. As I looked at it I thought of a great place to try it out! Here is a picture of it supporting the end of the tool holder. It REALLY helps eliminate the flex and chatter issues I was having.
 
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