There are several factors to consider when selecting the right sized angle grinder. But what you should understand is that a grinder’s size is determined by its discs, not the length of the overall tool. The size of the angle grinder you buy will depend on the size of the job you have. For example, a 7-inch grinder will cut through small pieces of wood in no time, but using that same grinder on a wooden beam will be more of a chore.
Typically, the most common size of angle grinder is 4.5 inches, meaning it uses discs that are 4.5 inches in diameter. This is a sufficient size for most workshop projects. Bigger wheels or discs will make deeper cuts.
If you have a concrete slab that’s 3 inches thick, a 4.5-inch wheel will not cut through it because the 4.5-inch wheel only sticks out at half the diameter – or only 2.25 inches. You’ll need a larger grinder for this project, such as the 9-inch model, which extends out at 4.5 inches.
Smaller discs at smaller circumferences will spin faster than larger discs, topping out at speeds over 11,000 RPM. These tinier wheels are ideal for cutting and polishing metal. However, smaller wheels are also susceptible to overheating. For this reason, experts recommend buying an angle grinder with an adjustable speed setting so you’re not constantly running at the highest speed.
Know your Amps
There are some other laws of physics to consider. The motor’s amp rating also determines grinder speed. Even though a 4.5-inch grinder is faster than a 6-inch grinder, the 6-inch grinder using a 13 amp motor will be just as fast, if not faster, than the 4.5-inch grinder with a 7 amp motor. Always review the RPM rating before making your decision.
Educate yourself on Safety
Whatever size grinder you decide to buy, safety should always be your top concern. It’s important to wear safety gear (like a face plate) to avoid getting hit with debris. We also recommend gloves to have more control over the tool’s spinning vibration.
For novices, it’s best to get used to a smaller grinder before upgrading to a larger one. Seven-inch models, for example, require two hands to operate because they put out so much power. 9-inch grinders were once very popular in industrial complexes but are now outlawed in many areas because they’ve caused so many accidents.
With a little due diligence, choosing an angle grinder that’s the right size for your needs is not as complicated as you think. Smaller grinders are perfect for most homeowner or DIY hobbyist needs – their lighter weight and small frame make them the ideal size for many projects. Not to mention, they require less energy to run. Understanding the overall differences in grinder sizes will help you find the perfect model for your needs.