smooth cuts with a lathe?

[constructor]

What kind of travel and turning speeds do you run to turn smooth barrel contours and which tool do you prefer?

 

[wnroscoe]

High RPM and slow feed will yeild a good, smooth finish, something in the 800-1000 RPM range with a feed of around .002" to start. Also, depending on the material your cutting, 416 Stainles or chrome moly, the depth of your cut will play somewhat of a factor. Tool style and sharpness will also play a factor. You will probably have to do your final finish with 320 grit paper working your way to 600 grit or finer depending on the finish your after.

 

[constructor]

Thanks, I haven't tried it that fast.

 

[TRECustom]

I'm not an expert on cutting tools, but I've found that if the material is something that can be cut with a high-speed cutting tool rather than a carbide tool, the cut will be noticeably smoother. Grinding the high-speed tools is a learned skill, and you have to run at a slower surface speed also, but the results are visibly smoother, including threads. The old-time machinists were masters at grinding their own tools and making beautiful cuts and threads. I usually wimp out though, and just run carbide. Do like I say, not like I do?

Try it, Tom

 

[Rustystud]

You have opened a kettle of worms with this thread. there are several schools of thought. First any machining induces stress in a barrel. Therefore barrels should be stress relieved then contoured and then stress releived again. You should consult with the likes of Mike Rock, Jack Kreiger, Tim North, Dan The 400 series stainless steels thend to machine sticky and string like unless the tooling is sharp and the cut is swift and deliberate.

Rustystud