Working on a wood lathe is one of the greatest experiences you can do when creating your pieces of art or just solid furniture. However, every wood lathe has its speed chart that needs to be understood and used properly to have the best results when cutting and shaping.
All wood lathe speed charts are just the basic suggested speeds you should be turning your pieces. The calculation for the speed chart is used to help you cut rough shapes into perfect round shapes, moving to faster speeds once the piece you are working on has been properly shaped.
You need to know many things about the speed charts that are used and the limitations that start appearing as your medium changes. Harder woods need slower speeds, while most smaller pieces you are cutting can be done at much faster speeds than other pieces.
What Is The Most Basic Wood Lathe Speed Chart?
Every manufacturer has a different speed chart for their different sized lathes, as larger lathes can handle turning larger pieces at much higher speeds. However, we know that most people have hand-me-down lathes or even bought lathes older than they are from old craftsmen.
These older lathes usually do not have their speed charts anymore, where the two standard speed charts are used. One focuses on spindle work and the other on face work. The speeds you should be using are slightly different, with the position of your tool sled and hands affecting everything.
Spindle Work
When a piece is put in the lathe to be turned from the side, we call it spindle work; you will be cutting and carving the piece from the side along the spindle. The speed you use here is the most important as the piece will hit your tools directly.
The smaller a piece of wood, the faster it can turn, as the outside of a piece turns much faster than the inside. This is why a piece over 6 inches should never be spun at faster than 500 rpm, as the piece will easily spin much faster.
In the chart below, the sizes on the left are how thick the piece is, with the sizes listed on top being the piece’s total length. You will see that it is recommended not to use an ordinary wood lathe at all after a certain length.
| Spindle Length | ||||||
| 6″(150mm) | 13″(305mm) | 18″(460mm) | 24″(610mm) | 36″(915mm) | 48″(1220mm) | |
| ½” (13mm) | 2500 | 2100 | 1500 | 900 | – | – |
| 2” (50mm) | 2000 | 2000 | 2000 | 1500 | 1200 | 1000 |
| 3” (75mm) | 1500 | 1500 | 1500 | 1500 | 1200 | 1200 |
| 4”(100mm) | 1000 | 1000 | 900 | 800 | 700 | 700 |
| 5”(125mm) | 900 | 900 | 700 | 700 | 600 | 600 |
| 6”(150mm) | 500 | 500 | 500 | 500 | 400 | 400 |
Lathe Speeds : Galloway Woodturners
Face Work
When you have finished shaping a piece, you will naturally want to cut and shape the facepiece. With shapes like bowls and plates, usually only being shaped with the face open so that you can cut in the hollow and smooth everything down as the piece takes shape.
Usually, these pieces are much larger than the parts that you would cut and shape on a lathe, which means that there is a different speed chart you should be using. The speed chart below is only a general guide as to how fast you should set a piece and then how quickly the outer edges will be turning.
When turning odd shapes and pieces, you will need to do a basic calculation to see if you are still in the safe range of what your lathe can handle.
| Face-Work Thickness | |||||
| 2″(50mm) | 3″(75mm) | 4″(100mm) | 5″(125mm) | 6″(150mm) | |
| 4″(100mm) | 1800 | 1600 | 1500 | 1400 | 1300 |
| 6″(150mm) | 1600 | 1500 | 1400 | 1300 | 1100 |
| 8″(200mm) | 1500 | 1400 | 1300 | 1100 | 900 |
| 10″(255mm) | 1400 | 1300 | 1100 | 900 | 800 |
| 12″(305mm) | 1300 | 1100 | 900 | 800 | 700 |
Lathe Speeds : Galloway Woodturners
How Does Lathe Speed Affect Lathe Cutting?
Several things are affected by the speed of your lathe, and you need to know what these are to ensure that you have the right speed. Many people assume that one speed will work with all the wood they have and that it never matter what size you are busy cutting.
However, if the speed is wrong, you can lose control of your cuts, have too much kickback, and even have the piece go flying out of the lathe as it is too unbalanced. Using the correct speeds on your wood lathe will ensure that you are always working safely to keep your cuts as good as possible.
Kickback From Cutting
Despite what many think, you can experience kickback when you are cutting on a lathe, especially when still working with something rough. If the piece has a large diameter and your lathe is spinning at its top speed, this kickback will be much more significant.
Too much kickback can severely damage your tools and also start bending your tool sled, causing your future cuts to be inaccurate. It is essential to ensure that you always have the right speed to ensure that your tools are safe and not in danger of having a piece going flying.
Loss Of Control
The loss of control is not necessarily your hands losing control of how and where you are cutting; instead, it is the lathe losing control. If your piece is unbalanced and spinning at the wrong speed, your entire lathe might start shaking, causing the lathe to become unbalanced and lose speed.
Further, if your lathe is not secured onto something solid or the table mounted on it is not heavy enough, the entire system might start shaking and tipping. This is why you need to ensure that the speed is just right to ensure that everything, including the lathe, does not suddenly topple over.
Smoothness Of Your Cuts
While going too fast will cause many problems, if you are not going fast enough, your overall shaping and cutting will be rough if going too slow. This is why you need to ensure that you have the perfect speed to ensure that you can easily cut the pieces smoothly and perfectly.
We always recommend going slightly faster than you initially thought; this will create smooth carvings and cuts throughout your workpiece. Just be careful not to cut too much at once when the piece is still smoothed out, or you might find the entire tool ripped out of your hand.
The Overall Quality Of Your Cuts
If you are busy cutting into the piece and your lathe is set to the wrong speed, your tool may not be easily cut, or it might start to burn the wood. A faster speed means that the tools won’t heat up too much, while slower speeds mean more accuracy.
Getting the speed right means that you can easily cut the face off a piece, create a perfectly round shape, and then create grooves without having missed cuts. Many novice craftsmen are too afraid to go fast with some pieces, make imperfect cuts, or even uneven shaping.
Control Over Cuts
Ironically enough, the slower your lathe turns, the more likely you will lose control over a cut you are making on your piece. If you are trying to make precise cuts, you need to have the piece turn fast enough that a complete cut is created every time the tool touches wood.
If the piece is turning too slowly, you may start cutting at different depths throughout the piece as you move in and out with the tool. Often you will find that when groove cutting or cutting pieces off, having a higher speed works better to provide exact control over the depth of a cut.
What Should The Lathe Speed Be For Different Types Of Woods?
Now that we understand the actual speed chart and how the speed of your lathe affects your overall cutting and shaping, we need to take a look at the types of wood. Generally speaking, when working on a lathe, the difference will be felt between soft and hardwoods.
Most craftsmen prefer to cut harder woods when working on a lathe because of the ease that it can be done. However, if you are using a wood lathe for the first time, it is understandable that you may want to try everything with a softer wood instead of using a hardwood that could be costly.
Lathe Speed For Harder Woods
Harder woods do much better with faster lathe speeds as they act more similarly to metals, which allows you to cut into the wood easily. Further, the wood will be more likely to give a consistent chip rate at a faster speed than catching on to the tool.
When cutting at a faster speed, you can also rely on hardwood to not easily crack when turning, giving you the chance to work with large pieces. This is often why those working with a lathe will want to use hardwoods instead of softwoods, as the wood handles are being spun much better.
Lathe Speed For Softer Woods
When working on softer woods with your lathe, we recommend using slightly slower speeds, not only because the wood might break apart at high speeds but because the wood can burn. When cutting too fast on softwood, you may charr the spot as the tool, and the wood heats up.
Charring is always a challenge to face when working on a lathe, but it is much more likely to happen when working with softwoods. Cutting at a slower speed with softwoods won’t stop your progress as much either, as you can cut slightly deeper and faster owing to the wood being so soft.
How To Determine The Speed A Piece Will Be Turning?
After you have become used to the speed chart and how the wood and size of the wood interacts with it, you need to learn how to calculate speed. Many people never learn that an exact equation can be used to determine the precise speed at which your piece will be moving.
However, if you have the calculation done properly, you can easily have the lathe always set to almost the perfect speed for the piece you are cutting. As you will naturally start learning how to do the calculation inside your head without writing it down on a piece of paper.
Diameter
The diameter of your piece needs to be measured in two parts, the diameter of the piece once you have cut off all the rough parts and the final diameter. This is important as you will have to change the speed to cut down the piece until it is the right size.
The outermost diameter needs to account for any large pieces that might bow out of the piece as well, as these will hit the tool first at a much higher speed. The larger a piece is in total diameter, the faster it will turn, requiring that you always consider how large something is.
Rpm
The rpm being measured is the rpm being supplied by the lathe head, measured at the exact middle piece, usually around one inch in thickness. This is where the belt is touching the lathe head and where the lathe will be measuring your speed.
The higher the RPM is at this spot, the higher the rpm will be on the outer edges of the pieces you are working on. This will be the constant that you can work with, as the diameter of the piece you are cutting will constantly change, becoming smaller as you start shaping the piece.
Calculation
The calculation is “RPM x Diameter = speed” this means that if you have an rpm of 800 and a piece 2 inches in diameter, the outermost edge will spin at 1600 rpm. You generally want the part you are working on to have an RPM of 1000 to 2000, preferably never any higher than that.
Using this calculation constantly will help you keep the piece turning fast enough to cut it without losing speed easily. However, it will also prevent you from going to a speed that is so high that the piece becomes a rocket that flies across the workshop instantly.
Conclusion
The lathe speed chart is used to ensure that your piece is never turning so fast that it can go flying and lose control. However, it will also help you learn how fast something should be turned so you can make perfect cuts and shapes without too much of a headache.
Having a good chart for your lathe will always be better than using a generic one!
References
Why do lathes run at different speeds? (moviecultists.com)
Safe Wood Lathe Speed (Calculate, Determine, Adjust RPM) – Turn A Wood Bowl
Recommended Wood Lathe Turning Speeds – Wood Turning Basics
Determining Safe Wood Lathe Speeds – Craft Supplies USA (woodturnerscatalog.com)