A universal grinder is a tool that grinds, files and finishes workpieces, most of which are made of metal. Universal grinders are different from most other types of grinders because their construction and arrangement allows them to work with an incredibly wide variety of materials and tools that require grinding processes. Most grinders manufactured are material-specific, meaning that they can only work on certain types of materials. For example, a metal grinder is different from a tool grinder, mainly because of the variance in grit, size and shape. All grinders, universal or not, work in a similar manner.
Grinders work by spinning a coarse surface at very high speeds, which slowly cuts away at small pieces on the applied material. They are typically used for finishing applications, where the surface or edge of a workpiece after undergoing its initial process needs finishing. One example of this would be a split piece of wood. Oftentimes, the new surface resulting from splitting the wood is very rough, and requires either a planer or a belt sander, another type of grinder, to give it a smooth finish.
Most grinders are, however, used for metalworking applications. Metalworking processes outside of careful machining usually produce rough, uneven surfaces that require some sort of finishing technique. An example of this would be plasma cutting metal, which while precise, often results in an uneven surface surrounding the cut end. While most flat surfaces or ends could undergo a milling process, such precise machining is often unnecessary for many jobs. As a result, a grinder or universal grinder is employed, which can give the workpiece a reasonably smooth finish that is adequate for most purposes.
The universal grinder can handle all of the aforementioned jobs and many more. These grinders can be very useful for facilities which work with a wider variety of materials. For those kinds of facilities, a universal grinder is a worthwhile investment, as it eliminates the need to purchase individual grinders for a certain material or process. This allows for workers to grind anything from metals to tools that require regular sharpening.
Since there are many different types of grinders, a universal grinder needs to incorporate as many varieties as possible. This can be done in many ways, as all of them require some sort of rotary movement, typically performed by an electric motor. As for changing grinder types to suit different materials, this can be done through changing the grit count or grinder shape, or even adjusting the torque and speed of rotation.