Royal Master TG12x4 Centerless Grinder

The Royal Master TG12x4 centerless grinder is an abrasive finishing tool where the workpiece is supported between two rotating wheels, without any workholding. Centerless grinding is not usually used for anything other than surface finishing, but it can be used for very high-volume runs. TG12x4s are precise to the micron level, and need only about 5 minutes of changeover time and 5 minutes to change the grinding wheel.

Centerless grinders have no need for workholding or mounting of parts. All the operator needs to do is insert the piece between the wheels. In most cases, the wheels will be oriented so that the part passes through the wheels automatically and only needs to be caught coming out of the other side.

Thus, centerless grinders are the premier choice for quickly finishing simple cylinders. But they can also round out-of-round workpiece blanks and reach roundness, surface finish, and dimensional tolerances better than most other processes. View specs on either of our rebuilt Royal Master TG12x4 grinders here or here.

We also have a CNC grinder available, in which the machine automatically feeds and catches the workpieces.

For answers to your questions or more information on Royal Master TG12x4s (or centerless grinders in general) call Liberty at 847-276-2761 or send us an email at

Liberty Machinery buys and sells high quality Royal Master TG-12x4 Centerless Grinders.

We are your trusted source for all types of centerless grinders and other used equipment.

Buy a Royal Master TG12x4 Sell your Royal Master TG12x4

Process Description: How does it work?

There are three main elements to a centerless grinder: the grinding wheel, the regulating wheel, and the workrest. Various other elements can control, for example, the rotation speed of the wheels or the height of the workrest. The shape of the part to be ground is also a factor, since centerless grinders can't be made to finish very complex parts.

The regulating wheel is usually made of a rubber bonded material and functions to rotate the workpiece so that every part of it is exposed to the grinding wheel. It also helps hold the part in place.

The grinding wheel is the piece that performs the abrasive action on the part. For centerless grinding, the wheel cannot be dressed in as many ways as with other methods, but it can accommodate angled pieces or stepped sections. This wheel rotates more quickly than the regulating wheel, creating friction between the two wheels and therefore grinding the workpiece between them.

The workrest is simply the place where the workpiece sits. This may be one or two blades or a slanted bed that keeps the workpiece at the lowest point and enables much greater roundness.

The Royal Master TG12x4 can perform two different kinds of centerless grinding:

Through-feed grinding is the most common method. The part automatically moves completely through the two wheels and comes out on the other side.

In-feed grinding allows for some dressing of the grinding wheel. It is used when the operator wants to grind a part that has many different diameters at different points.

Common Industries

Screw machine     Hydraulics     Electronics     Automotive     Medical

Sell Your Royal Master TG12x4 Centerless Grinder

Liberty is always looking for used centerless grinders to buy for inventory. Contact us and let us know what you have for sale. We’ll be happy to give you a free quote.

Check our Inventory for a Used Royal Master Centerless Grinder

Click below to see our current inventory and request a free quote. Someone will be in touch very soon.

See our used centerless grinders for sale.

Visit our YouTube channel for under-power videos!


  1. Robert H. Todd, Dell K. Allen, Leo Alting, Manufacturing Processes Reference Guide (Industrial Press Inc: 1994), 21.
  2. Chris Koepfer, "Centerless Grinding: Not Magic!" Modern Machine Shop Magazine, 12/15/2000.
  3.  "Centerless Grinding," Processes: Machining, eFunda, Inc.
  4. "Infeed grinding." Total Grinding Solutions.