How to Buy a Used Lathe

Like if this guide is helpful
How to Buy a Used Lathe

A lathe is a machine tool that rotates a piece of material on an axis to perform a number of tasks, such as cutting, turning, or drilling, using tools applied to the workpiece. Lathes come in a variety of sizes, from small machines used in jewellery and watchmaking, to industrial sized lathes that can be up to 10 metres long. They are used in metalworking and woodworking, although woodworking lathes tend to have simpler designs.

Owning a lathe allows a business to create anything from ornamental candlesticks to spare parts for vehicles or appliances. However, buying a lathe is an expensive exercise. Purchasing a used lathe is an excellent way to keep costs down, provided the buyer knows how to evaluate the item. In order to understand how to do this, a brief explanation of lathe parts is required. Used lathes can be bought at auctions, from estate sales and secondhand shops, from specialist dealers, and online, from sites like eBay.

Parts of Lathes

Understanding how to evaluate a used lathe depends on knowing what the different parts of a lathe are called and what each part does. The table below lists common lathe components with a brief description.

Part of Lathe

Description

Bed

Foundation of machine

Holds the headstock, tailstock, and carriage in alignment

May be a gap or removable section near the headstock to allow the turning of large diameter pieces

Bed ways

Surfaces of bed

Finely machined

Carriage and tailstock slide on the ways

Saddle

Casting that fits on top of the bed

Apron

Plate fastened to the front of the saddle

Features gears and controls that allow the carriage to be moved up and down the bed

Mechanism inside engages screw cutting and powered tool feeds

Leadscrew often passes through the apron

Compound slide rest

Made up of cross and top slide

Cross slide moves across the bed

Top slide can be swivelled and locked into a new position

Carriage

Made up of the saddle, apron, cross and top slides

Headstock

Mounted to bed

Holds mechanisms that allow the headstock spindle to turn at varying speeds

Headstock spindle

End of spindle machined to carry the drive plate, chuck, faceplate, collets, or other attachments

Attachments hold the item to be machined

Back gear

Gear mounted at the back of the headstock

Allows chuck to turn with a higher torque

May be referred to as a BG lathe

BGSC is a back geared and screw cutting lathe

Leadscrew

Threaded rod running along the front of the bed

Gears connect the spindle to the leadscrew and the leadscrew to the lathe carriage

Carriage and cutting tool move a set distance for each turn of the spindle

Tailstock

Slides along the bed to be locked into position at a convenient point

Features the spindle; the level of protrusion from the casting can be adjusted by hand, lever, or screw feed

Carries the dead centre to support the opposite end of the work held in the headstock

Countershaft

Reduces the lathe's spindle speed

Change wheels

Gears that conduct the drive from the headstock spindle to the leadscrew

Mainly used to adjust the leadscrew speed when cutting threads

The names of lathe components are not standardised and may differ from manual to manual or between manufacturers. In addition, the names of parts usually differ in the United States and the United Kingdom. For the most accurate information, check the lathe's manual.

Evaluating a Used Lathe

Evaluating the used lathe effectively is crucial, as these machines tend to be fairly expensive. Before buying, if possible, machine a piece of metal to get a feel for the lathe and learn about possible imperfections. Each component should be checked to ensure that no major repairs are required.

Check the Lathe Bed

The lathe bed is the backbone of the unit, so the condition of this part determines the accuracy of the lathe. The ways should be perfectly parallel. Check for wear near the headstock as this is where most of the work takes place, leading to uneven wear of the ways. Uneven wear means that the carriage and cutting tool do not travel parallel to the workpiece. All used lathes show some signs of wear; the secret lies in determining whether the wear impacts accuracy.

Look at the bed ways to determine whether the original finish has been worn off. Research the specific machine or simply check immediately underneath the headstock to see the original finish. Bearing surfaces do not move along the full width of the bed ways, so check for a ridge on the ways that indicates wear. Try to lift the carriage off the bed. There should not be much movement. As a final measure, move the carriage as close as possible to the headstock, tighten the carriage binding screw until the carriage can no longer move. Loosen the screw until the carriage moves smoothly and crank the carriage towards the opposite side. It should move across without binding.

If possible, place a piece of stock of at least 150 millimetres long and 50 millimetres in diameter in the chuck. Machine a cut along the length of it before measuring the diameter at three points along the length, using a micrometer. If the diameters vary by more than two hundredths of a millimetre, the lathe is no longer cutting along a parallel plane and all future workpieces will be tapered.

Check the Headstock

The headstock spindle and spindle bearings should be in good condition. If possible, run the machine at a high speed, listening for any unusual sounds, and feel whether the bearings heat up after it has been running for a while. The bearings should not be particularly hot. If running the machine is not possible, check the spindle and feel the bearings to establish whether they are in good condition. Look at all the spindle attachments and threading. If the lathe has back gears check for chipped, broken, or worn teeth or listen to them run to establish whether they need to be replaced.

Check the Change Wheels and Gearbox

When evaluating gears, always check for worn or broken teeth. When checking the change wheels and gearbox, also look for cracked or damaged mountings, worn bushings, and whether the components are lubricated properly. Grease tends to trap metal chips and filings, which can damage the gears. Although some manufacturers recommend using grease instead of oil for lubricating these parts, be cautious if the gears have been greased.

Additional Checks

Take the time to check the lathe for cracks, bumps, dents, and signs that the machine may have toppled over. Check the obvious areas that would be damaged is this happened, such as protruding parts, side surfaces, and corners. If it is not possible to access all the parts or gears that should be checked, run the machine and listen for unusual noises. Make sure that the top slide has not been damaged by being run into the chuck while it is spinning. The tailstock should be aligned with the headstock to ensure accuracy while machining and all components should be undamaged and in good working condition. In short, the lathe should not make any unusual noises while running, machined stock should not taper in diameter, and there should be no obvious signs of damage to any parts, accessories, or components.

Buying a Used Lathe on eBay

Searching for a used lathe on eBay is simple. Type a phrase, such as "used Clarke lathe" in the search field, which is located on every page, to see the items for sale. Choose the most appropriate category and item features to refine your search. To narrow or expand the list of lathes displayed, use the advanced search option.

Before You Buy on eBay

Before buying on eBay, evaluate the item and the seller. Read the full item description by navigating to the item listing page and clicking on the individual listing. You can also find details such as buying options, the seller's accepted payment methods, and the seller's feedback information in this section. Most lathes for sale are listed as collection only due to their size and weight. Look for a local seller to make collection easier and ask whether you can view the lathe before buying it. To contact the seller, click on the "Ask a question" link.

Check the seller's feedback to learn about him or her before buying. Click on the number next to the seller's username to see what other buyers have to say about his or her products and customer service. This gives you an accurate idea of what to expect from specific sellers.

Conclusion

Buying a used lathe is a great way to save money on an expensive piece of equipment. However, buying used is only a good idea if the machine is evaluated properly. An understanding of the machine's components and parts is important as it gives the buyer a better understanding of how the parts work together to make the machine function effectively. If possible, research each machine according to its make and model to find out about common problems and user complaints before viewing.

Each component should be checked for wear or damage. It is best to listen to the machine while it is running to establish whether there is any damage to the gears. The bed ways should not be unevenly worn as this affects the accuracy of the work performed. Similarly, misaligned head and tailstocks cause tapering. In addition to gears working correctly, it is important to ensure that there are no other worn or broken components that could cause tapering in the workpiece.

When shopping for a used lathe on eBay, try to find a local seller. Most sellers list these large items as collection only, so choosing a local seller makes it easier to arrange transport for the machine and it may also be possible to view and test it before buying.

Have something to share, create your own guide... Write a guide
Explore more guides