Used Surface Grinders

A surface grinder is a precision machine used to create flat, smooth, and accurate surfaces on metal (and certain other materials).
Surface grinders are commonly used for toolrooms, maintenance departments, mold shops, and production environments where
flatness, parallelism, and surface finish matter. They are ideal for squaring parts, finishing plates,
bringing components to thickness, and producing consistent mating surfaces.

This category includes common formats such as 6" x 18" surface grinders, which are popular because they fit many everyday grinding tasks
while maintaining a manageable footprint.


Filter by Tonnage / Size

Stroke (in Inches)

Bed Area (Inches Right to Left)

Weight Capacity (lbs.)

Width (in Inches)

Thickness / O.D. (in Inches)


Featured example: 6" x 18" Abrasive Surface Grinder with Magnetic Chuck (Model R-618)

You may see machines like a 6" x 18" Abrasive Surface Grinder with Magnetic Chuck (example:
Model R-618). The “6 x 18” size typically refers to the approximate table or chuck working area and gives a quick sense of the part sizes
the grinder is suited for. In practice, capacity depends on table travel, fixture clearance, and how the part is held.

What a surface grinder can do

  • Flatten and square parts: Produce flat reference surfaces and improve overall part geometry.
  • Bring parts to thickness: Hold consistent thickness and parallelism across plates and components.
  • Improve surface finish: Create clean mating surfaces and improve contact quality.
  • Refinish tooling and fixtures: Maintain parallels, spacers, fixture plates, and machine components.

Magnetic chucks: why they matter

Many surface grinders use a magnetic chuck to hold ferrous workpieces securely during grinding. A magnet chuck can speed up setup,
improve repeatability, and reduce the need for complex fixturing on flat parts. Magnetic holding works best on clean, flat, ferrous material with good contact
area. Thin parts, warped parts, or non-magnetic materials often require alternative workholding methods.

Common surface grinder configurations

  • Manual surface grinders: Operator-controlled feed and movement, common in toolrooms and maintenance.
  • Automatic feed grinders: Add automated table movement and/or downfeed for consistency and throughput.
  • Reciprocating table (most common): The table moves back and forth under the wheel.
  • Rotary table (specialized): The work rotates under the wheel, often used for round parts or high-throughput flat grinding.

Grinding wheels and finishes (simple overview)

Grinding wheel selection is a big driver of results. Wheel type, grit, grade, and dressing approach influence stock removal rate, heat generation, and finish.
In general:

  • Coarser grit: Faster material removal, rougher finish.
  • Finer grit: Smoother finish, slower removal.
  • Proper dressing: Helps the wheel cut cleanly and improves finish consistency.

Surface grinder FAQs (beginner-friendly)

What is a surface grinder used for?

Surface grinders are used to grind flat surfaces and achieve accurate thickness, flatness, and finish. Common work includes plates, parallels,
fixture components, blocks, and parts that need a clean, precise mating surface.

What does “6 x 18” mean on a surface grinder?

It usually refers to the approximate size of the table or magnetic chuck area (about 6 inches by 18 inches). Actual usable capacity depends on table travel,
part clearance, and workholding method.

Do surface grinders only work on steel?

Surface grinders are commonly used on steel, but they can also be used on other materials with the correct wheel and setup.
Workholding may change for non-magnetic materials since a standard magnetic chuck will not hold them.

How flat can a surface grinder grind?

Flatness depends on machine condition, wheel selection, dressing, technique, and the part itself. Clean setup and controlled heat are key.
For precision work, small changes in technique and dressing can make a noticeable difference.

What causes burn marks during grinding?

Grinding burns often come from too much heat, which can be caused by heavy passes, dull wheels, incorrect wheel choice, poor dressing, or inadequate coolant
(if coolant is used). Managing heat is critical for both finish and material integrity.

Do I need coolant on a surface grinder?

Some grinding can be done dry, but coolant often helps control heat, improve wheel life, and reduce burning risk, especially when removing more material
or working on heat-sensitive parts. The best approach depends on material, wheel, and the finish you need.

What is “dressing” a grinding wheel?

Dressing restores the wheel’s cutting surface and shape. A properly dressed wheel cuts cleaner, runs cooler, and produces more consistent finishes.
Dressing method and frequency affect both removal rate and surface finish.

How does a magnetic chuck work?

A magnetic chuck uses a controllable magnetic field to hold ferrous workpieces flat against the chuck surface. Clean contact, good surface area,
and proper clamping are important for safe grinding.

What should I know before grinding thin parts?

Thin parts can warp from heat and magnetic pull, and they may not have enough stiffness for aggressive grinding. Light passes, good dressing,
and heat control help reduce distortion.

What are common wear items or maintenance points?

  • Wheel condition and dressing tools
  • Magnetic chuck surface condition and cleanliness
  • Ways and lubrication
  • Table movement smoothness and alignment
  • Spindle condition and vibration

What information helps match a surface grinder to my needs?

  • Typical part size and thickness
  • Material type (ferrous vs non-ferrous)
  • Required flatness and finish expectations
  • Manual vs automatic feed preference
  • Whether you want coolant capability