Knowledge You Can Build On — Est. 1998
lathe speeds for each tool
Richard L. Snyder Sr.
Hello,
What would be the initial start-up and max. speed for the basic lathe tools, ie. gouge,skew,parting,etc.
Thanks, Rick
PS. ALL THE INFO. I HAVE RECEIVED HERE AT THE TURNING SECTION HAS BEEN FANTASTIC!!!
more a matter of the wood than the tool
John K Jordan
For me, speed is more a matter of the size and type of wood spinning. Large blanks for bowls should be slow. Small things like boxes, goblets, and spindles can be faster. Blanks that have voids and cracks might come apart at very high speeds. Large blanks that come apart or come off the lathe at high speed can do a lot of damage.
In general, for spindles I turn about as fast as the lathe can go, about 3200 rpm for my lathe. This is for gouge, skew, etc. If the spindle was a big and long banister I would turn slower, but anything 2" or under I turn wide open. If a small spindle breaks or comes off the lathe, it will not smash your head in.
In general, higher speed gives a smoother surface. The smoothness comes from how much you move the tool for every revolution. If the tool is moved too fast down a cylinder you get a spiral instead of a smooth surface. With a slow speed the tool must be moved VERY slowly. With a high speed, the tool can be moved quicker for the same effect, but it might be easier to make a smoother motion if not creeping across the tool rest.
That said, with very thin spindles (1/8" or so) sometimes I have to turn the speed down a bit do deal with vibration if other things don't work.
If a bowl blank is unbalanced because it is not yet trued, I use the highest speed that will not cause "excessive" vibration on my lathe, whatever that is, then turn the speed up as the blank is trued and the work progresses. This afternoon I turned a 9' square-ish platter from 2" thick hard maple. Before I removed a lot of wood and lightened the blank, I got a vibration around 1200 rpm or so. But this smoothed out above about 1800 so I turned the whole thing somewhere around 2500 rpm. (guessing here since I rarely look at the speed numbers)
If you watch some of the experts, speed is king! The first time I saw Jimmy Clewes turn an off-center winged piece with the speed wide open it was a little scary! People sitting in the "line of fire" at the demo were leaning out of the way, as if that would help!
If you are a beginning turner, the higher speed might be intimidating. However, you use exactly the same cuts and tool presentation regardless of the speed. If something bad happens, such as a big catch on a spindle, it probably won't matter if the speed is 500 or 2500. A heavy face turning, however, can be dangerous if it comes off the lathe - a 12" bowl turning at 2000 rpm has a LOT more energy in it than at 1000 rpm.
JKJ
Re: lathe speeds for each tool *LINK*
David Walser
As John said, safe spinning speed has more to do with the size of the turning blank than the tool that you're using to shape the blank. Many other factors affect the speed at which you can turn safely: the integrity of the blank (blanks with voids & defects should be turned, if they're turned at all, more slowly than a blank of solid wood), the method of holding the blank onto the lathe, the orientation of the blank, etc.
Several years ago, Dale Nish devised a formula to guide new turners in determining a safe turning speed. His formula is discussed in the article linked below. At the end of the article there is an embedded video that discusses lathe safety. There are lots of good safety tips and the video is well worth watching.
Re: lathe speeds for each tool
robo hippy
The nice thing about variable speed is that it makes it simple to start at a slow speed, and ramp it up as needed. I never even tried to figure out formulas or what my speed was, I just turn it up or down till it feels right, or with bowl blanks, till the blank is running smooth and even.
From Pat's Fan over at Wood Net, "When sphincter tightening exceeds chuck tightening, you have a problem". Being comfortable is important as well as knowing what is safe. Being safe depends on the wood being solid or weak. Knowing comes from experience, and some times we have to learn the hard way, so at least stand out of the line of fire.
robo hippy
Re: lathe speeds for each tool
john Lucas
Ditto what Reed just said. You need to be comfortable. As you gain skill you will probably increase the speed more and feel more safe. The main thing when you start turning is to be safe and slow speeds are safer. For a long time I never turned over 1200 rpm. I will often do a demo and show people how they can get the same cut turning really slow. It's more about tool presentation and sharpeness than speed. As you gain confidence you will just naturally speed the lathe up and there advantages to speed but they are best used by advanced turners.
Re: lathe speeds for each tool
David Bassett
Machinists are much more quantitative than than I've found turners to be. It's all about surface speed and material for them. Wood is less homogeneous and the ranges would therefore be wider, and perhaps less useful. As an example of what I'm trying to describe: a 6" diameter bowl at 1200 RPM would move passed the tool at about 1880 SFPM. But a 1/2" diameter spindle at 1200 RPM would be at about 160 SFPM. Same RPM, but very different cutting speed at the tool's edge. Throw in cross-grain, moisture content, etc. and characterizing "ideal" speeds is difficult.
5 RPM For EVERY tool
Brad Vietje
WHA ?!? Is this an April 1st response?
No, not at all. You've gotten very good answers from some very well-respected and skilled turners & instructors, and I agree with all posts so far. BUT -- here's just another perspective. Since beginners are going to get a lot of catches before all these confusing factors are fully mastered, I like to demonstrate and try each tool while rotating the lathe by hand.
I had a student last weekend that attended his first turning club meeting ever, and I agreed to stay after the meeting to help him learn how to turn a bowl (I had brought a Boxelder blank as part of my demo). I would have preferred to start with a spindle blank, but I was asked to show him how to turn a bowl.
After I rounded up the blank, I showed him how to stand, hold the tool and anchor his left hand on the rest, and how I present the tool to the wood -- all with the lathe off. Then I moved to the outboard side of the headstock so I could turn the lathe by hand, and we went over how to move your body slowly to the left until you just pick up the cut, and how to then hold that angle and sweep it around the curve of the bowl (spindle would have been better here!).
We did this 4-5 times before even turning the lathe on, including what happens when you go too far, open the flute up too much, etc... I like to show a number of possible disasters at hand-rotation speed, so they'll know how to avoid these -- and why.
I'd suggest doing this with each tool, or for each new use of that tool (say -- inside the bowl as opposed to the outside), and it's great to have a helper turn the lathe. They don't have to know anything about turning, but it helps to turn the lathe the right direction.
When we went to the inside, we went through this again, as well as with a scraper, and what angles work (& why) and which do not. He left having gotten a good, clean cut from foot to rim on the outside, and another from rim to bottom on the inside (probably at about 600 RPM), but we certainly didn't start there.
Just one fella's way of teaching -- maybe it will help you see potential problems develop before they become dangerous and scary events, and all while feeling totally comfortable that you won't get hurt -- cuz you really could.
Safe spinning,
Brad Vietje
Newbury, VT
Re: 5 RPM For EVERY tool
John K Jordan
That's perfect. That's the way I always start too, read that in a book long ago - It really works, you can see exactly what the tool is doing. Once the "Ah Ha!" light bulb comes on and they can handle the basic presentation, the speed comes up.
I've thought it would be nice to put a slow motor and a belt on the handwheel of my 1642 to turn continuously at hand speed.
JKJ
Re: 5 RPM For EVERY tool
Gbalock
Excellent idea. Makes me want to add a handle to my hand wheel!
Re: 5 RPM For EVERY tool
John K Jordan
>Makes me want to add a handle to my hand wheel!
Ah, you mean a crank handle? THAT would be easy and so much smoother than twisting by hand. Hmm, have to remember to remove it before turning the lathe...
Or better, maybe a friction-fit rod with a crank that can be pulled out of the spindle bore easily? That would be very easy to make and use.
JKJ
Re: 5 RPM For EVERY tool
Brad Vietje
...and pulling it out would be a whole lotta safer, too!
I really like the idea of a small aux motor drive for teaching. It would be pretty easy to turn a hand wheel that would accept a small belt, and use a little sewing machine motor or one scavenged from the local recycling center -- free I like. If the motor sat on a nearby bench or small wooden arm, it would be no big deal to pop the belt on for a teaching session, and store it for normal work.
Safe spinning,
Brad Vietje
Newbury, VT
Re: 5 RPM For EVERY tool
John K Jordan
It occurred to me that even easier than a belt would be a rubber wheel or shaft covered with a piece of rubber hose that would press up against the hand wheel. Have to put the motor on a swivel arm, maybe with a spring to hold the contact. A small DC geared motor would be perfect. My buddy is a motor maniac - I'll bet he has one.
Last night I swapped out one of my Jet 1642s for a PM3520b. The handwheel on the PM would work better with a rubber shaft in contact while the belt would be better with the Jet.
JKJ
