While metal and other types of lathes do exist, the wood lathe is still a unique tool in the woodworking realm. It allows for the turning of wood into various cylindrical, conical or circular convex or concave shapes, or into objects that combine two or more of these shapes.
In more concrete terms, many objects can be created with a wood lathe like chair or table legs, balusters, bowls, vases, pens, Christmas tree ornaments, toys like spinning tops and more.
This article explains what a wood lathe is, how it works and what are its main components. We will study the following subjects:
How a Wood Lathe Works
The principle of how a wood lathe works is relatively simple. The tool makes a piece of wood, which can be called a turning blank as long as it has not yet been carved, spin around itself. While the turning blank is spinning, the user moves forward various specialty wood chisels or gouges in order to remove material with their cutting edges and form the blank into the wanted shape. These specialty chisels and gouges are called turning tools.
The workpiece rotates toward the turning tool’s edge and not away from it. Otherwise, the turning tool would only glide on the workpiece and would not remove any wood. Another way to explain the rotation direction is to say that the top of the workpiece moves toward the user. That being said, on some lathes it is possible to invert the spinning direction. This feature can be useful when turning bowls or sanding; it is indeed possible and very practical to sand a turned piece directly on the wood lathe.
The Wood Lathe Bed and some General Considerations
We will now dwell, among other things, on the main parts of a wood lathe.
Let’s start with the part of the lathe named the bed. It serves as a base for the tool and it is also the part that all the other components are resting upon, with the possible exception of the motor. Sometime, the lathe’s motor is not attached to the rest of the lathe but is instead mounted, for example, on a workbench. In this case the motor will make the lathe run with the help of a long belt. This kind of setup is mostly seen on older models.
On small lathes produced in the recent years, the motor will often be mounted at the bottom of the bed in order to keep the footprint to a minimum while on big lathes the motor will most likely be mounted on the left of a component named the headstock. We will study this part of the lathe later in this article.
The bed length is what mostly dictates the maximum length of a piece of wood that can be mounted on a lathe between two accessories named the drive centre and the live centre (the drive centre is spun by the motor while the live centre moves freely). This length is called the distance between centres. Still, other variables come into play like the use of other accessories that, when installed, can make the distance between centres shorter.
If the tailstock were to be removed from the lathe, there would technically be no limit to the length of the workpiece, but this kind of setup would be impractical; long workpieces often have to be supported from both of their ends.
Wood lathes comes in many sizes and can be classified into different categories. These categories can be established on the basis of different criteria and their number may vary from one source to the other since their classifying is arbitrary to some degree. Nevertheless, they are often divided into the three categories that we will dwell upon in the following of this article.
The Mini Lathe
The mini lathe comes first in ascending size order. Its distance between centres usually ranges from 10 to 18 inches (1 inch equals 2.54 cm). The maximum diameter of the workpiece, which is called the “swing over bed” or just “swing,” is often between 8 and 10 inches. Note that for many users, the swing will often be more important than the distance between centres.
The mini lathe suits both beginner turners or ones who intend to only craft small objects. This is the type of lathe that I own partly because I have a tiny workshop, which means I need to make choices when it’s time to acquire new tools. For example, it would be impossible to house a big model of lathe in my shop while keeping my other stationary tools as they are. It is fine with me since my workshop size is only convenient for making small objects like sculptures or wall decors. Budget also influenced my choice. These concerns may also impact the type of lathe you choose.
The Midi Lathe
The midi lathe, which is the median size of lathe, comes next. It typically has a swing of 12 inches, sometimes 14. Its distance between centres generally ranges from about 14 to 24 inches. The distance between centres of these lathes can sometimes be increased with a bed extension that can be bought separately for some models of midi lathes. An extension of this type can give a midi lathe the same distance between centres as a full-size lathe.
Often, these lathes will have additional features when compared to the mini lathe like an electronic speed control dial or an RPM gauge.
The Full-Size Lathe
The full-size lathes are the biggest wood lathes available. They generally have a distance between centres of 32 to 45 inches, sometimes even more. Their swing typically ranges from 16 to 20 inches and again, sometimes more than that.
These wood lathes are sold with a stand included, unlike the mini and midi lathes for which a stand must be bought separately when it is available for a given model. Most of the time, though, these smaller lathes are bolted to a workbench. The full-size lathes are generally those that come with the most features. Of course, they also tend to be the most expensive lathes available.
The Headstock and the Tailstock
Wood lathes are almost always equipped with a headstock to the left of the lathe and a tailstock that can be moved to its right. Most of the time, the headstock cannot be moved. The headstock and the tailstock are crucial components of the lathe that can receive many accessories. These accessories, in turn, allow to mount wood on the lathe (see the section on the spindle below) or sometime to perform other tasks. Some other functionalities are also featured on the headstock:
The power switch is often located on the headstock, just like the motor, although on smaller lathes these components might be located on the bed. Most of the time there will also be a system of belt and pulleys located inside the headstock in order to change the lathe speed.
Additional features will sometimes be added to the headstock or somewhere else on a lathe, especially on bigger and more expensive models. They can for example be equipped with an electronic speed control knob or lever, an RPM gauge, a switch that inverts the motor rotation direction and an indexing wheel that allows to stop the workpiece rotation at a given point. This last function is especially useful to drill holes at precise locations on the workpiece with the help of a jig.
Also, some lathes will allow for their headstock to be moved freely on the bed.
The reason anyone would want to move the headstock is that by removing the tailstock from the bed and moving the headstock completely to the right, pieces of a very large diameter and exceeding the swing of the lathe can be turned without hitting the bed. Additional accessories, which are sold separately, will be needed to turn large pieces of wood this way.
An important feature of the headstock and the tailstock is the height at which accessories can be attached to them with respect to the bed of the lathe. This is because this height is what determines the swing of the lathe, which is, as you may recall, the maximum diameter of a workpiece that can be turned on the lathe. As we already mentioned it, the swing is often even more important than the distance between centres.
The movable tailstock can be fixed in place at any point on the bed as long as it has clearance for it. The tailstock can be equipped with, among other accessories, the live centre, which spins freely in order to provide additional support to the workpiece without impeding its rotation. The tailstock is also equipped with a hand wheel that makes the live centre or any other accessories it is equipped with move forward or backward as it is turned one way or another.
This functionality is very important since it is used to mount wood in order to turn between centres. It would technically be possible to make do without it, but that would be impractical.
The maximum distance the tailstock can move its accessories is called the quill travel. It generally varies with respect to the lathe size. A mini lathe typically has a quill travel from one and a half to two inches while a midi lathe has about two or three inches of quill travel and a full-size lathe around four inches.
The spindle is located on the headstock. It is quite small when compared to the total size of the lathe, yet it plays a crucial role among the lathe components. The spindle is coupled to the motor and possesses threads which allows for accessories to be screwed on and an opening on which other types of accessories can be inserted into. In both cases, these accessories are used to mount the workpiece on the lathe.
The spindle opening is a socket shaped so a standardized tapered shank can be inserted into it. This type of system is called a machine taper. The drive centre, for example, is mounted to the lathe this way.
The tailstock also has a machine taper socket in which the live centre, or other accessories like a drill chuck, are inserted.
One of the main points to consider when comparing wood lathe motors is their power. Wood lathes can have up to 2 hp or 3 hp, or even 5 hp in some rare cases (hp is the abbreviation for horsepower, a unit of measurement of power) and it can indeed be useful or even necessary to have a powerful lathe motor.
That being said, my small wood lathe only has 1/3 hp and it works fine for me since I mainly make small decorative objects with my lathe. A motor of this size won’t be enough for turning large bowls conveniently, though. Even for what I use my lathe for, it tends to stall when I apply too much pressure with my turning tools on the largest workpiece sections in diameter.
If this isn’t a serious problem for me, others will prefer to have a motor with a higher torque, especially at low speed. Having a good torque at low speed can be a real advantage for turning on a wood lathe.
Mini lathes will generally have between 1/3 and 3/4 hp. Midi lathes often have about 1 hp. A full-size lathe will most likely have from 1 1/2 to 2 hp, sometimes more.
Another factor to consider when choosing a lathe is the speed range its motor can work at. The wood lathes that are able to run both at high speed and at very low speed will be the most versatile and effective for some tasks. I am satisfied with the speed range of my lathe going from 500 to 3500 rpm, but some turners will prefer a lathe that allows to go at a higher speed or at a much lower speed like 50 rpm in order to do finishing work directly on the lathe (a speed this low isn’t effective for turning).
The speed control system
A criterion that can be just as important as the motor power or its speed range is the type speed control system it is equipped with, be it a simple step pulley system or a system that offers the possibility of electronically control its speed.
Indeed, the lathe speed must frequently be changed when turning wood. For example, when a blank with sharp 90 degrees corners is mounted on the lathe, the lathe should first be set at a very low speed, which can then be increased when the workpiece is starting to be cylindrical. Then, the lathe could also be sped up at some other point during the turning. In fact, the lathe speed can be modified as many times as the user consider it is pertinent.
The way the speed is modified on a given lathe depends on the way it was conceived.
The oldest and, in my opinion, the least convenient method is to change the lathe speed with the help of a simple step pulley system. In order to obtain a specific speed, the belt must be manually placed at a given spot on the pulley. The lathes using this system typically have only five or six different speeds.
I much prefer variable speed lathes, which are equipped with a speed control knob or lever. Most of these lathes feature a step pulley that only has two or three steps and that allows them to run at different speed ranges. In addition, their speed control knob (or lever) allows the user to run the lathe at any speed that is within the selected speed range. This kind of system allows to better control the speed of the lathe and is easy to use.
There are even lathes that only have a speed control knob or lever and no step pulley system to fiddle with. This is the case of my small lathe. I find this system very convenient but it is not commonplace.
The Tool Rest
Wood lathes have a built-in tool rest. It is an essential component for any type of turning. It would indeed be neither safe nor efficient to move a turning tool directly into the moving workpiece without any other support than what is provided by the hands of the user. The turning tool would then be very hard, not to say impossible to control.
Because of this, when using his lathe the turner should put the turning tool against the tool rest while holding it firmly but not too tightly.
The tool rest post is inserted into a component of the lathe named the banjo. This banjo can slide horizontally on the wood lathe bed and be locked in place with the help of a lever. The tool rest height can also be adjusted by sliding its post and then locking it in place with another lever located at the top of the banjo. The tool rest angle can also be set in any direction as long as it doesn’t bump into the workpiece or other parts of the lathe.
The tool rest has to be positioned as close as possible to the workpiece without bumping into it when it rotates but also without supporting the turning tool by its edge. In either case, the tool rest must be moved further away.
After having positioned the tool rest, a complete revolution of the workpiece must be made by hand in order to be sure it won’t bump into the tool rest.
The tool rest has to be brought closer to the workpiece from time to time as material is removed with the turning tool, which makes the diameter of the workpiece shrink in size. If the tool rest is positioned too far from the workpiece at any point during the turning process it may cause vibrations which, in turn, can make the turning tool leave undesirable tool marks on the workpiece.
As for the tool rest height, it most often has to be adjusted so the edge of the turning tool makes contact with the centre of the workpiece. This principle implies that the optimal height of the tool rest varies with respect to the tool used and the angle it is held in.
Il est possible d’acheter des supports d’outil supplémentaires pour son tour. Ils viennent dans une variété de grandeurs et de formes destinées à des besoins de tournages différents. Il faut dans ce cas s’assurer d’acheter un support d’outil dont la base sera compatible avec l’ouverture de la semelle. En Amérique du Nord, les tours mini seront typiquement compatibles avec une base de support d’outil de 5/8 de pouce tandis que les tours midi récents et les tours d’atelier seront généralement compatibles avec une base de support d’outil de 1 pouce. Les modèles plus anciens de tours midi seront peut-être quant à eux compatibles avec une base de 5/8 de pouce.
For the Lord God is a sun and shield; the Lord bestows favor and honor; no good thing does he withhold from those whose walk is blameless. Psalm 84:11