RICHARD
Buying guide: what to check before buying a used grinding machine
A grinding machine is one of those machines that often stays in production for many years without being replaced — which makes the used market both attractive and a bit tricky. Condition varies enormously depending on how the machine has been maintained, what material it has been run against, and how much it has actually been used. Before you sign a deal, you should go through the machine systematically. Here's a practical checklist to bring along to the viewing.
1. Check the condition of belts and rollers
Start with what's visible right away: belts, rollers, and contact wheels. If the rollers are worn, uneven, or have developed grooves, it will affect the grinding result regardless of how new the machine looks on the surface. Feel for unevenness by hand and check whether the rubber coating is cracked or hardened. A worn contact wheel is a cheap spare part, but if several rollers need replacing at once, the cost adds up quickly.
If you're looking at a universal grinder such as the Holytek, it's especially important to check that all grinding stations perform equally — often one station is used more than others, causing uneven wear across the machine.
2. Test the machine's accuracy and tolerances
A grinding machine needs to hold tight tolerances, otherwise you lose the whole point of the investment. Ask the seller to run a test piece if possible, and measure the result with calipers or a dial indicator. Check:
- Parallelism between infeed and outfeed
- Evenness of the thickness setting across the entire working width
- Whether the machine drifts or gives deviating measurements after running for a while (which can indicate thermal issues in bearings or spindle)
Older precision grinders, such as Stehle/Schneeberger, are known for high accuracy when properly maintained — but that's exactly why it's especially important to verify that the machine hasn't lost its original precision over the years.
3. Go through the electrical cabinet, motors, and control systems
Open the electrical cabinet if you can, or ask an electrician to do it for you. Look for:
- Signs of overheating (discolored cables, burnt components)
- Whether the control system is original or has been rebuilt
- Whether spare parts and circuit boards are still available
Older electronics can work perfectly fine, but if a circuit board fails and is no longer manufactured, the whole machine can become difficult to repair. Ask specifically whether this has happened before and how it was resolved.
4. Check spindle and bearing condition
The spindle and bearings are where the most expensive repairs sit. Listen for uneven noises, feel for vibrations, and check for play in the spindle when the machine is idling. A spindle with binding or abnormal noise should either be heavily discounted in price or avoided entirely, unless you already have a plan and budget for refurbishment.
5. Dust extraction and safety equipment
Grinding machines generate large amounts of dust, and a functioning extraction system is crucial both for the working environment and for the machine's lifespan — dust accumulating in bearings and motors wears them down hard over time. Check that the extraction connections are complete and that guards, emergency stops, and any light curtains work as they should. If safety equipment is missing or outdated, it may mean extra costs to meet today's requirements before the machine can be put into operation.
6. History, maintenance log, and usage level
Ask for as much history as possible: service log, previous repairs, and if possible an estimate of running hours. A machine that has run one shift under controlled conditions is often a better buy than one that has run around the clock in a high-production environment, even if it looks newer in photos.
7. Flexibility and capacity for your production
Finally — think through what you actually need. A combination machine like the RK Kombi 11 can be a smart choice if you have varied production and need multiple functions in one machine, while a dedicated grinder like the Weinig R 912 is better suited if you run high volumes of the same type of work. Match the machine's capacity to your real production volume instead of buying "just in case" — overcapacity costs both in purchase price and running costs.
Summary
A used grinding machine can be an excellent investment if you know what to look for. Check rollers and wear parts, test accuracy in practice, review electronics and spindle, and make sure dust extraction and safety are up to standard. Always ask for history and compare the machine's capacity against your actual needs before deciding.
FAQ
How do I know if a grinding machine still holds its original precision? The best way is to ask for a test piece to be run and measure the result carefully. Check parallelism and evenness across the entire working width, and whether the measurements change after running for a while.
Is it worth buying a grinding machine with a worn contact wheel? Yes, if the price is right — contact wheels are relatively cheap to replace. Factor the cost into your offer, but avoid machines where several rollers and bearings simultaneously show signs of wear.
What's most important to check in the electrical cabinet of an older grinding machine? Look for signs of overheating, check whether the control system is original, and ask whether spare parts for circuit boards are still available. Any rebuilt electrical systems should always be documented and explained by the seller.