CNC MACHINES

Surface, Internal and Tool and Cutter Grinders Compared

Published: 

Surface, Internal and Tool and Cutter Grinders Compared

A surface grinder finishes flat faces, an internal grinder finishes bores, and a tool and cutter grinder sharpens or makes cutting tools. A center hole grinder is a specialist machine that grinds the center holes in shafts so they run true between centers. Pick the grinder by the feature you need to finish, then judge it by condition.

Surface Grinders

The common surface grinder runs a wheel on a horizontal spindle over a table that moves back and forth under it. Steel parts are usually held down on a magnetic chuck. The job is flat, parallel and square: die plates, fixture parts, wear strips and anything that needs a ground face, often right after it comes off a vertical machining center. Almost every toolroom has one.

Older manual surface grinders are simple machines. If the ways and spindle are good, age matters less than condition. The Reid HYT surface grinder in our used grinders stock dates to 1962. On any surface grinder, check:

  • Spindle bearings. Run it, listen, and feel the wheel head for heat and play.
  • Table ways. Look for scoring and check that the table moves smooth with no sticky spots.
  • The magnetic chuck. Make sure it holds and releases. A worn chuck top can be ground flat in place.
  • The wheel dresser, guards and coolant or dust collection.

Internal Grinders

An internal grinder, or ID grinder, puts a small wheel on a high speed spindle and runs it inside a bore. The part spins in a workhead chuck while the wheel moves in and out. Bearing races, bushings, gears and hydraulic parts are the usual work. When a bore needs a finish and size you cannot hold with boring heads or reamers, this is the machine.

The Bryant Lectraline LL2U in our stock is listed as a multi surface and internal grinder, built in 2009. On an internal grinder, check workhead runout, the condition of the wheel spindles and quills that come with it, and any in process gauging. Ask how many wheel spindles are included, since they wear and are specific to the machine.

A gear shaver is a different machine, but it often shows up in the same shops. We have a National GCR-12 gear shaver and more on our used gear machinery page.

Tool and Cutter Grinders

A tool and cutter grinder sharpens end mills, drills, reamers and form tools. Manual versions are built for resharpening. CNC versions can grind complete tools from blanks and repeat the same geometry every time. Insert tooling, like our Walter indexable drill, takes new inserts instead of a regrind.

We have an Oerlikon B10 CNC tool and cutter grinder. On a CNC tool grinder, check that the software and wheel packs come with it, run every axis, and check the probe if it has one. The tools it sharpens end up in holders like our end mill holders and collet chucks.

Center Hole Grinders

Shafts that get turned or ground between centers are only as true as their center holes. Heat treat can move a part, so many shops grind the center holes after heat treat and before the final OD grind. A center hole grinder does just that one job.

Our Technica 5100-815 center hole grinder is a 1999 machine. It fits a shaft line that already has used CNC lathes on the front end and a heat treat furnace in the middle.

Where Honing Fits

Honing is not grinding, but it finishes bores too. A hone runs abrasive stones in a bore to bring it to size and roundness with a fine finish. We have a Sunnen MBH-12090D hone listed with our horizontal machines.

What to Check on Any Used Grinder

  • Spindle. The spindle is the heart of a grinder. Noise, heat or play means spindle work, and that is often the most expensive repair on the machine.
  • Ways and hydraulics. Look for scoring and leaks. Check that the table and slides move at a steady rate.
  • Coolant and filtration. Grinding swarf is fine and gets everywhere. Look at the tank, the filter and the pump.
  • Foundation. Grinders do not like vibration. Plan a solid, level spot away from stamping presses and heavy machining.
  • Clean parts. Parts should be clean before they go on the chuck. A parts washer helps keep chips and oil off the grinder.
  • Deburring. Not every part needs a precision grinder. For rough grinding and edge break, look at robotic material removal or a dedicated machine like our Acme single station deburr.

Grinders in Stock

Stock changes, so check the pages for what is here today.

For the rest of our machine tools, see used CNC machines and industrial liquidations. If you want to spread out payments, look at our equipment financing.

Related Guides

Have a Grinder to Sell?

We buy used grinders and machine tools, one machine or a whole plant. Go to our sell your used machinery page, or ask about machinery appraisals.

Machines ship FOB Imlay City, Michigan, and the buyer arranges freight. For details on any grinder, call 586-752-0090, extension 1 for sales, or contact our sales team.