Lathe speeds

[George Conklin]

Hey guys
What's the right lathe speed for bowl turning? I've been doing all of my turning at 500rpms. Is that too slow. Most of what I have turned has been under ten inches in diameter and two inches thick.

Thanks for your help.

George

[Jim Becker]

Starting out, it should likely be lower than 500 rpm in many cases, especially for things above 5-6". One the piece is balanced, you can speed it up a bit. The larger the piece the lower your safe upper limit. I NEVER turn bowls or vessels above 1200 rpm and for the larger pieces, stay south of that. By larger, I'm saying 10" and above.

[Keith Burns]

I started out turning everything as fast as I could, thought it did a better job. Wrong! I now turn virtually everything except pens and small spindles at 350 rpm.

[Glenn Hodges]

Amen to what Jim said. If you can't figure out the speed watch when the lathe starts dancing and shaking with the piece on it, you better back off on the speed, and I mean back off quick or call your friends and ask them to rush over if they want to see an accident that might involve blood, hair, and possible teeth displacment. When you start out with an unbalanced piece of wood to turn a bowl slower is much better than fast, but go as fast as your lathe and the wood will allow. Your speed can be increased as the bowl becomes rounder and more balanced. Remember our leader is Columbus....we live in a round world.

[Bill Stevener]

I turn bowls and hollow forms in the range of 2750 - 3900 RPM.

However, they are never much larger than 0.5" :D

There is no speed table, as one may find when "drilling" different types of materials, provided for use when one is "turning" wood. The factors governing the speed at which a piece will be turned is countless. The size may be the first consideration. The shape and the amount of preparation before mounting the same may be the next. Another all important factor is the species of wood. One may turn a flawless piece of Chery one day, and the next day turn a piece of maple with a large knot in the side. The Maple will not withstand the same speed as the Chery, as the knot will have it constantly out of balance. The state of the piece of wood often governs the speed, as to weather it is green (wet) or dry. The same applies for the length of the piece. One will not turn a 40" piece as fast as a 12" piece. Additionally, the speed is relative to the stage of the turning.
Then, one of great importance, which will determine the turning speed, is the tool being used.

All in all, the lathe, wood and tools will speak, if the work is vibrating, back it down 10-20, or more. When all three are in line, you will find the sweet spot. Generally, that's a safe, effective and efficient turning speed.


Bill>>>>>>>>>>>>>>>>:)

[Jim Becker]

To add to this conversation...it's all about "rim speed", not spindle speed. How fast is the workpiece turning at the outer edge? That is where the limit for safety is.

[George Conklin]

The reason I posted this question was because I seem to have less tear-out when I kicked the speed up from 500 to 750 on one bowl I tried to turn. I was curious if speed had anything to do with that.

I cut my bowl blanks as close to true as possible on the band saw first, so they are not too out of round.

And again, my stuff is usually 5 to 10 inches in diameter.

George

[Andy Hoyt]

George - If tearout is a big issue, try presenting the cutting edge to the bowl at differing aspects and angles. I've found that to be most helpful. Of course, each piece will have its own unique resolution.

As to the general speed issue, the previous posts are dead on target. I use the listen, feel, and observe technique to establish rotation speed. I have no idea what the actual rpms might be when turning, just doesn't matter.

[George Conklin]

George - If tearout is a big issue, try presenting the cutting edge to the bowl at differing aspects and angles. I've found that to be most helpful. Of course, each piece will have its own unique resolution.

Roger that, Andy. The more practice I get, the more I find that out. I need to get over the newbie- lets see what I can turn as fast as I can because I'm impatient bla bla bla- to working on better technique practices.

George

[Kent Weakley]

Hey George,

There is a formula to use. Take the diameter of the bowl divided by 9000. So a 10" bowl should stay under 900 rpm and no piece, that's not a spindle turning, should go over 1000 rpm. Check out this article which covers the topic in great detail (https://turnawoodbowl.com/safe-wood-lathe-speed-calculation/).

[John Keeton]

Kent, this thread is 13 years old!!

[Bob Bergstrom]

Kent, this thread is 13 years old!!

And that’s why John was a good lawyer. ⚖️⚖️

[John Keeton]

Thanks, Bob! Operative word there - “was.” Five years into retirement and enjoying every minute.