Wood lathes are high-speed lathes that are generally small in size and ideal for machining soft materials.
These machines consist of a hand-held cutting tool that provides high flexibility to produce complex shapes.
But can we use a wood lathe to machine metal?
Wood lathes are not recommended for turning metal because of their low-torque, high-speed, and hand-held tool configuration. Machining metals require high torque and clamped tools to deliver strong cutting forces. However, they can be used to perform simple machining operations on soft and non-porous metals like aluminum and brass.
This article discusses the possibility of machining metal on a wood lathe and talks about the things to be wary of during the process.
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Using wood lathe for metal- Is it possible?
The low torque also prevents you from performing heavy cuts on the metal, as this poses the risk of stalling the spindle.
All these factors limit the operations that a wood lathe can perform on metals.
Furthermore, hard and porous metals cannot be turned at high speeds, as the friction developed will result in overheating of the metal and the tool.
At the same time, most metals need greater force to hold the tools against their surface to machine effectively and prevent vibrations.
Using a wood lathe requires a hand-held tool, which is inefficient at delivering strong cutting force, making them inefficient at machining hard metals.
Metal Lathes vs Wood lathes
Both lathes have similar working and perform similar machining operations. So, what exactly is the difference between wood lathes and metal lathes?
Metal lathes and wood lathes have their key differences in the spindle RPM and torque.
Wood is a bad conductor of heat, which allows it to be turned at high RPM without the risk of overheating the workpiece.
Moreover, the lower material density of wood requires comparatively lower machining torque than metals.
Metals, on the other hand, are turned at low RPM to prevent the workpiece or the tool from overheating, and the spindle torque required in metal lathes is generally higher due to the high material density of metals.
Generally, both metal and wood lathes have a belt-driven system where the motor is coupled with the spindle using a timing belt.
However, there are high-end metal lathes that house a direct-drive system, in which the motor is directly mounted on the spindle.
This provides greater power output and higher precision for controlling the speed of the spindle.
Furthermore, metal lathes deliver a strong cutting force and therefore have a comparatively more robust construction than wood lathes.
Apart from the construction, these lathes also differ in the type of lathe cutting tools used for machining.
Metal lathes have a dedicated tool post that can hold the tool firmly against the surface of the metal with minimum vibrations.
Wood lathes, on the other hand, have hand-held cutting tools. This arrangement is possible because wood lathes deliver a comparatively weaker cutting force to remove the material from the workpiece.
However, wood lathes have a tool rest that helps in positioning the cutting tool and improves its stability.
As a result, wood lathes are manually operated machines, whereas metal lathes can be easily automated.
This reduces the complexity of wood lathes and allows you to perform woodworking operations with minimal prior training.
Whereas metal lathes are complex machines that require an experienced and skillful operator to perform safe and efficient machining operations.
Depending upon their construction and applications, these complex metal lathes are available in various types, such as center lathe, turret lathe, capstan lathe, swiss lathe, CNC lathe, multi-spindle lathe, gunsmith lathe, etc.
Things to keep in Mind when Machining Metal on a Wood Lathe
Machining metal on a wood lathe is not generally advisable.
However, with certain precautionary measures and good process control, you can use wood lathes for performing simple machining operations on soft metals.
It must be ensured that the workpiece is firmly secured in the chuck of your wood lathe machine.
The chips flying off of your metal workpiece will be hotter compared to chips from a wooden workpiece, and can even cut or burn your hand, if comes in contact.
Hence wearing thin rubber gloves and safety goggles is advisable. Also, you should never attempt to clean the chips while the machine is running.
Installing a mist or flood cutting fluid delivery system can enhance the functionality of the lathe to cut metal workpieces.
Generally, synthetic lathe coolants are used for machining metals, as they provide high heat capacity with good lubricity.
To prevent the tool from bending or breaking and possibly injuring your hand while making deep cuts, it is advised to make multiple passes with shallow cuts.
If possible, it is recommended to build a DIY tool post for machining metal on your wood lathe. The tool post will facilitate delivering stronger cutting force, reduce chatter (vibrations), and increase accuracy.
You should also be careful about the angle at which you are holding your tool, and generally, it is advised to turn the workpiece from top rather than sides.
Turning from the side poses the risk of tool getting tugged between the slide rest and the spinning workpiece. This may bend or break the tool and possibly injure the operator.
What is chatter and how to prevent it?
Chatter is the vibrations caused when a tool presses against the workpiece.
It can be identified by quirky loud noises and is also visible on the surface of the material in the form of circular ‘helixes’.
Chatter degrades the surface finish of the workpiece and, in some cases, might also cause geometric deformations in the shape of the material.
In the long run, these vibrations cause the tools to lose their sharpness, rendering them dull and inefficient for machining.
Chatter can be reduced by reducing the freeplay in parts of the lathe machine.
The lathe should have a robust construction and the toolpost should be firm with no loose attachments.
The chuck should hold the material tightly with no room for wiggle. Even a slight wobble of the workpiece can cause significant vibrations.
You should be careful about the length of the workpieces, as long workpieces tend to deflect under strong cutting forces, which significantly increases the vibrations.
Using a tail stock wherever possible will also reduce the chatter.
Tools to be used for machining metal on a wood lathe
High-speed steel (HSS) or carbide-coated tools provide high strength and are therefore ideal for machining metal on a wood lathe.
For machining brass, it is recommended to use tools with low or zero top rake. For example, scrapers generally have a low top-rake, making them an excellent choice for machining brass on wood lathe.
For turning aluminum on a wood lathe, it is recommended to use a short beveled bowl gouge or a graver at low spindle speed settings.
The hand-held tool of wood lathes is prone to vibrations, thereby producing chatter.
As a result, a secondary operation to file the chatter marks is required to improve the surface finish of the workpiece.
When machining metal using handheld tools on a wood lathe, it is strongly advised to use tools with a sturdy handle to prevent the risk of injury.
Can you Use a Metal Lathe for Wood?
Unlike metals, wooden workpieces are soft and are comparatively less dense, and therefore do not require high torque for machining.
However, they require a fast spindle speed to glide the cutting tool and produce a smooth surface finish.
Metal lathes can be used for machining wood but at the cost of surface finish and flexibility.
The hand-held cutting tool of wood lathes is ideal for carving complex contours for woodworking projects like furniture and wooden artwork.
Although the tool post of metal lathes provides higher accuracy in positioning the tool, it cannot be used for producing complex shapes, unless using an expensive CNC metal lathe.
Furthermore, the comparatively low speed of metal lathes will result in a poor surface finish, and using a metal tool for machining wood can generate heat, thereby causing burn marks on the wooden workpiece.
Therefore, woodworking projects carved on a metal lathe will generally require extensive sanding to attain a smooth surface finish.
Is it possible to machine metal on a wood lathe? The general answer is yes, you can.
Wood lathes can be used to machine metal workpiece but at the cost of surface finish and accuracy.
However, it is not recommended to use wood lathe for machining hard and porous metals like steel that require high torque and strong cutting force to scrape material from their surface.
The hand-held tool of wood lathes is not ideal for metal work but can be used for making shallow cuts in soft metals.
Customizing your wood lathe with a DIY tool post will provide the ability to deliver a stronger cutting force, thereby enhancing its metal processing capabilities.
Using hand-held tools when machining metal on wood lathes increases the risk of injury, and therefore it is recommended to follow safety precautions like using tools with handles and wearing safety gear.
Frequently asked questions (FAQ)
How can we customize a wood lathe for metal projects?
The primary requirement of metalworking is strong cutting force and high torque. Although you can't improve the torque of your wood lathe, you can install a DIY tool post to deliver a strong cutting force for machining metals. Furthermore, using a good quality coolant system will keep the temperature in control and prevent the workpiece from overheating, when machined at high speed.
Is it safe to wear welding or leather gloves while turning metal on a wood lathe?
No, it is not safe to wear welding or leather gloves while turning metal on a wood lathe. This is because these gloves tend to be larger with overhangs on every finger. This may cause a part of the glove to get stuck between the spinning workpiece and the slide rest and cause an injury to your hand. Wearing thin rubber gloves that fit tightly on your hands is a safer option.
Is it possible to turn steel on a wood lathe?
It is possible to perform minor machining of steel on a wood lathe, but it is not advisable. Steel is a hard metal that needs high torque and strong cutting force to remove material from its surface. Wood lathes cannot provide such high torque, and the hand-held tool is not suitable for delivering strong cutting forces. Furthermore, it is ideal to turn steel at low speeds to prevent heating of the workpiece, which further makes it unsuitable for machining on wood lathes, as they generally operate at high speeds.