Grinding 101 – Basics for the Shop Floor

By: Scott Bahr

Grinding ranges in both type and technique, like many processes related to fabrication and manufacturing. It is largely based on the objectives at hand. All of the different grinding techniques have various applications and use cases, and they require different tools. With that in mind, understanding each type of grinding is essential when selecting the best technique. Being well-informed ultimately leads to maximum quality and process efficiency.

Precision grinding

This type of grinding, also known as die grinding, is known to be high-speed, precise, and detailed. Typically done with a handheld grinder, precision grinding can be done in small or confined spaces or when precise cuts are needed. A precision grinder has teeth that cut out a chip of the material each time they make contact. The operator must take into account how much pressure they should apply and the speed at which the precision grinder should be used. If too much force is used, the tool might jam and stall. The area where the tool touches the material should be minimized. This gives the operator more control, the ability to increase and decrease pressure, and results in a better overall grind.

Rough grinding/cutting off

Rough grinding is used to remove as much material as possible, especially when the finish of the surface is not very important. Rough grinding can also be used to cut off pieces of a material that aren’t necessary, smooth edges, shape, or remove material to create or expand a cavity. There are numerous tools that can be used for this type of grinding, but the most familiar ones are likely the angle grinder and the vertical grinder. Both use either a handheld tool or a fixed machine along with a cutting wheel. The wheels come in various shapes and sizes. Using a handheld tool provides less guidance than using a stationary machine. Rough grinding machines are much more powerful than precision grinders because they need to move faster and affect a larger part of the material.

Surface grinding 

Surface grinding, also known as sanding and polishing, does exactly what its name suggests. This process mainly focuses on the surface of a material, and does not usually manipulate the actual shape and structure of an object. These are large machines, ranging in size but almost always stationary, use a wheel to smooth the surface. The techniques used in surface grinding require that the material be kept in motion. If the material is kept in one spot, it might result in unevenness or a coarse surface. This process can work in several stages, including sanding, cleaning, deburring, polishing, and finishing.

Deciding which process and technique to use when grinding is dependent on the work you are doing as well as what is best for your operation. An excellent resource, one which informed some of the information here, is the Pocket Guide to Grinding Technique.