Atlas 3995 Chattering

[markba633csi]

Atlas- the rubber goes in before the name goes on

 

[ARC-170]

I can part just fine with my Atlas Craftsman 101.07403. I go slower and use LOTS of cutting fluid (flood it). I made a parting tool (out of steel) that gives a little, which seems to help. Here's a photo:

 

[Rickinlexky]

Atlas- the rubber goes in before the name goes on

that wasn't nice =

I haven't had trouble parting with my 70 year old Craftsman 618, which has to be close to the bottom of the Atlas barrel. It does like brass and aluminum better than it likes steel stock, but it will do what I ask of it.

 

[markba633csi]

Just joking- besides I have two of them

 

[machinistnoob]

that wasn't nice =

I haven't had trouble parting with my 70 year old Craftsman 618, which has to be close to the bottom of the Atlas barrel. It does like brass and aluminum better than it likes steel stock, but it will do what I ask of it.

Agreed

 

[Rickinlexky]

Now I feel better - I was afraid its feelings were going to be hurt.

 

[markba633csi]

Going back to the OPs first post, judging by the photo either the material is from outer space or the cutting tools are to blame
What do you other folks think? Gotta be something basic. The faced end of that bar looks like it's rubbing not cutting

OP: Can you post some close ups of your cutting tools? (end-on views)

 

[pontiac428]

Going back to the OPs first post, judging by the photo either the material is from outer space or the cutting tools are to blame
What do you other folks think? Gotta be something basic. The faced end of that bar looks like it's rubbing not cutting

OP: Can you post some close ups of your cutting tools? (end-on views)

Based on the pics added to post #1, I'd have to agree. Mild steel can be tough to get a good finish on, but proper tool height, sharp tooling, and the right cutting speeds should give acceptable results. The Atlas Manual of Lathe Operation (MOLO) from a year close to your lathe's manufacture should give you a good start on setting up the cut.

 

[markba633csi]

The 3995 is one of the most rigid and hefty of the 12" Atlas line so it's not likely a lathe fault
Poor rake or poor relief on the tool would do that. Carbides cause a lot of headaches too

Edit: I believe your tools are the issue- I don't see much rake or relief on them and they don't look very sharp.

You want a "knife edge" type of profile to cut well

Here is a page from the "how to run a lathe" book by South Bend: old information but still useful for HSS

 

[4WHLDRFTN]

Copper shim under the tool in the post. Compound @ 45° and a sharp HSS. If it still chatters ..something is looooossseee.