Choosing the Right Grinder for the Job

choosing the right grinder

A basic component of any welder’s toolbox is a decent angle grinder. There are few tools more versatile than a grinder. However, not all grinders are equal. Therefore, trying to choose the right one can be difficult. We will discuss a few tips for choosing the right grinder size for the job.

Choosing the Right Grinder


Bigger Grinders are Better for Larger Jobs

Many don’t understand that a grinder’s discs determines its size, not the length of the overall machine. Grinders with bigger wheel discs are longer than the smaller counterparts. However, this is because a bigger handle is necessary to control the wheel.

For instance, a 4.5-inch angle grinder is the most common size. It utilizes wheel discs that are 4.5 inches in diameter. A 7-inch grinder uses a 7-inch disc, and so on. It is important to understand that the bigger sizes use larger wheels. Wheel size is especially relevant for large jobs.

If you only occasionally use a grinder for odd cutting jobs, then purchasing a smaller size works well. A 5-inch grinder can cut through several feet of wood in no time at all. However, using that same grinder on a larger project like cutting beams for a deck would quickly become a chore.

Bigger Wheels Make Deeper Cuts

Grinder sizes are particularly important once you consider the materials. For instance, grinders of any size can cut through wood, though smaller grinders will get into trouble with particularly thick pieces. However, not all grinders can handle durable materials such as stone and concrete. Not only are they incredibly strong, these materials tend to also be thick.

For instance, a concrete slab can be easily three inches wide. A 4.5 angle grinder has a blade that is 4.5-inches in diameter. This means the blade extends 2.25-inches for the center in each direction. As a result, it is not physically able to cut through 4 inch concrete. Select a larger grinder when a deep cuts are necessary, such as a 9-inch grinder. The blade of this grinder extends 4.5 inches from the center.

Smaller Grinders Spin at Faster Speeds

A smaller circle with a tiny circumference will spin at faster speeds compared to a large circle with a greater circumference. In fact, it isn’t uncommon to see a 4.5-inch grinder top out speeds over 11,000 RPM, giving these tiny grinders the power to cut and polish metal. This is why smaller grinders are more susceptible to overheating than their larger counterparts.

If a 7-inch grinder is spinning at speeds of 5,000 RPM while it is sanding a floor, its greater design and slower speed is generating less heat than a 4.5-inch grinder that is spinning away at 10,000 RPM. While the greater speed gives the grinder more power, it also makes it much easier to fail. In fact, it’s recommended to buy a smaller grinder that comes with adjustable speed settings. Therefore, you’re not constantly operating on the highest setting.


These are just a few tips for selecting the right grinder size for the job. Choosing the right grinder size is not as complicated as it may appear. Small grinders are ideal for small projects, as their smaller discs and lighter weight make them easier to control. They also utilize less energy and come in cordless varieties. However, just because they are small doesn’t mean they can’t perform the job well. Most small grinders have higher RPM speeds than larger grinders. Brazos Industries uses the appropriate grinders to ensure your project is done correctly and efficiently.

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