A lathe, also called “the mother of all machine tools,” is equipment fundamentally used to shape metal, wood, and other materials. As it is one of the basic and the most versatile tools, it is paramount for every machinist to know how to use a lathe to establish a successful repair and offer perfect maintenance of the parts.
What is a Lathe?
To simply define lathing it is a process of shaping, cutting, drilling, sanding, and deformation. It is a precision-based tool; all the cuts and shapes created using a lathe are immaculate. Lathes work on a ‘holding and rotating mechanism”, that is, it rotates the workpiece around an immovable cutting tool to get the desired result. Its use ranges from drilling and cutting in high machinery to shaping home decor items or musical instruments.
History of Lathe
It is believed to have jump-started the backstage Industrial Revolution, which means it was an essential tool in the industries used to make other machines and parts. The basic design of the small lathe machine offered cutting and shaping of the cylindrical metal workpiece.
What are Lathes Used for?
Different operations performed on the lathe are:
- Plain Turning
- Filling and Polishing
- Taper Turning
There are 3 types of lathes:
- Engine lathe
- Turret lathe
- Special Purpose lathe
How to Use a Lathe?
Before using a lathe for your projects ensure the setup of lathe is professional enough for the project you are handling. Following are the detailed procedures to use metal and wood lathes.
How to Use a Wood Lathe?
Step-1 : Select a Suitable Lathe
For beginners, table top lathe machines are a perfect choice. However, wood lathes are designed differently with different mechanisms of operation; therefore, it is an essential step to select the best wood lathe that suits your requirement.
Step-2 : Arrange Prerequisites for Lathe Work
- Cutting fluids: They’re used to lubricate the lathe machining to ensure a smooth finish. It also increases the piece’s life and helps in cooling it off. Common cutting fluids are Lard oil, Mineral oil, soda water mixture, etc.
- Toolbox: The basic tools like screwdrivers, wrenches, etc., are extremely useful in securing the workpiece and making a lathe work smoothly.
Step-3 : Understand Components of a Lathe
- Bed: The bed holds the working parts of the lathe. It is the heaviest part of the machine. It provides a base for the movement of carriage assembly and is where headstock and tailstock are attached and supported.
- Legs: The legs sustain the weight of the machine. They are usually screwed to the floor. Some lathes are industrially used; therefore, the size is huge and doesn’t require movement. Some other lathes are portable.
- Headstock: The headstock spindle is a hollow cylindrical shaft that enables a drive from motor to work holding devices. It can be seen on the left side of the machine body; it is the joining point of driving pulleys, back gears, headstock spindle, live centre, and the feed reverse gear.
- Gear Box: As the name suggests, it consists of several gears. Its position is below the headstock.
- Carriage: The carriage is located between the headstock and tailstock. It supports and feeds the tool against the job during operation. It consists of an H-shaped saddle, a cross slide, the compound rest, the tool post, and the apron.
- Tailstock: It is located immediately opposite a headstock. It is adjustable and can accommodate different lengths of the workpiece. A tailstock clamp is provided to lock the tailstock at any desired position.
Step-4 : Choose and Select Operation and the Tools
Since a lathe offers various operations, you’ll have to select one for your objective and prepare the lathe accordingly. Chisels (lathe tools) have long, curved handles to ensure a perfect grip while turning. In addition, there are several turner tools available that can be used.
Step-5 : Select a Wood Stock and Prepare
There is no hard and fast rule for choosing a wood type, but it is advised to use a softwood like Southern yellow pine. Woods with excessive resinous oil sap, knotty, splinter nature, or very high moisture contents do not give good results for beginner woodturners. The workpiece is required to be square to establish perfectly cylindrical results. Cut the stock to the desired length and mark centres on each end.
Step-6 : Position the Workpiece
Place the tool-rest so that it runs parallel along the length of the stock with the preferred distance of 3/4th of an inch between them.
Step-7 : Turn the Lathe On
Hold the tool you selected for turning operation and spin the workpiece once before turning on the machine (at the lowest speed). Spin the stock such that it doesn’t tool-rest. Place the cutting edge tool on the stock while moving towards perpendicular motion. Initially, cut small chips off to get the hang of it. Then, move the cutting edge parallel to the rotation of the workpiece. The cut chips must fly away from you in the right or left direction.
Step-8 : Check Frequently
Stop regularly working to check the fault lines or asymmetric cuts along the edges. Instead, work on the stock until you receive angular ends.
Step-9 : Better Finish
Increase the lathe speed to make the workpiece rounder, and the cutting edge must barely touch wood as the speed would be enough to make any changes. Slow tool movement will bring out the finer details and a smoother finish.
Step-10 : Sand the Stock
After switching off the machine, move the tool to rest away from the piece. Next, select the suitable sandpaper based on your wood choice, turn the lathe on again, and sand the surface with back-and-forth movement along the length.
How to Use a Metal Lathe?
Metal lathes are different from wood lathes as one can easily use them for any material with tough and sharp tool bits. However, the usage of metal lathes is similar to wood lathes.
Step-1 : Select a Suitable Lathe and Set It Up
Select a suitable beginner metal lathe for your projects before setting it up. Benchtop lathes are usually mounted on a sturdy bench or pedestal. Ensure that all electrical devices are well connected and that the circuit is complete.
Step-2 : Mount the Workpiece
The workpiece should be given a light test-whirl to ensure it doesn’t touch the toolset during rotation. Once everything seems functional, mount the workpiece on the headstock, put the guard on, select the speed as low and turn on the lathe.
Step-3 : Lubricate and Rotate
Adjust the crank handle of the machine tool according to your requirement. You should start the process with the lubrication of the oil pump. The length of the turning tool is generally not more than 2.5 times the thickness of the knife. Turn on the machine and move your desired cutting tool along the length of the stick to scrape off the surface of it. More rigid materials require a slower speed setting, taking longer to cut through. One safety measure to keep in mind is that all balls must be perfectly attached and tight.
Step-4 : Second Pass and Final Touch
Turn the machine off to inspect the stock status before going over it again with the tool at varying speeds, based on the requirement. Finally, clean the machine and knock down each handle to show zero reading.
There are some safety guidelines you have to follow while using a lathe.
- Do not wear long sleeves; remove any ring or watches.
- Always wear safety gear and eye protection.
- Lathes must be well lubricated and adjusted correctly.
- Check for loose nuts and bolts as they can cause dangerous accidents.
- Always stop the lathe before making any adjustments.
- Handle heavy chucks and other tools with care.
- Know where the emergency stop is before operating the lathe.
- For hand lathe use two hands when sanding the workpiece.
- Check the shields and guards.
- Keep your tools sharp.
- Take help from a professional.
- Keep the work area well-lit and clean.
- Always keep a close watch in case of an emergency.
- Do not operate in case of excessive vibration.
- Free spin your workpieces before turning the lathe on to ensure they don’t touch the tool rest.
A lathe is commonly known as the machine that could essentially be used to “build itself.” It is commonly believed that a person using only a metal lathe could create a working version of another lathe. As an all-rounder with so many benefits, it offers the basic steps for wood or metal workers to get familiar with their work, which is why it is essential to know how to operate a lathe.