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How To Choose The Angle Grinders Size
- Jul 25, 2018 -

Angle grinders are generally classified by the nominal diameter of the accessories they use. The typical cutting and grinding accessories are described as ‘abrasive,’ with particles bonded onto a wheel or disk. The materials used, and the construction of the wheel or disk, will depend on the application. Discs used for cutting steel will be different to discs used for grinding stone, for example.

The abrasive particles ‘scrape’ away material as they spin. Eventually they dull and break away from the bond, exposing new, sharp particles. This means the diameter of the wheel or disk decreases in use, until it is too small to be useful.


The Four-Inch Grinder These three grinders are all 4-inch diameter tools, and are the cheapest ones you’ll generally find on the market for mass consumption. This is the first size I bought and it’s well suited to motorcycle tasks.

When you’re using grinders on a regular basis it can be tedious changing accessories all the time. When these grinders were on sale, I bought two. I can set up a cutting disk in one grinder and a grinding wheel or a sanding disk in another one. This speeds up my workflow.



The Nine-Inch Grinder When I was remodeling our house, I needed to cut up some concrete, so I purchased the cheapest 9-inch grinder I could find, since I didn’t want to hire a demolition saw. This was great for big heavy jobs like concrete and roughly cutting up large steel sections.

There is no ‘finesse’ with a 9-inch grinder, so it’s not suitable for motorcycle work. Don’t waste your money unless you have other needs for it. Bigger is not better in this case.



The Five-Inch Grinder . This size has turned out to be very useful for one reason: it will cut through 1-inch/25mm tubing from one side in a single cut. This is a common size used on older motorcycles, along with 3/4″ and 7/8″, or 19mm and 22mm for the metric world.

If you’re cutting this tubing using a 4-inch grinder, you might only get three-quarters of the way through and then you have to turn around and cut from the other side. This makes a clean, straight cut more difficult. The accessories are a little bit more expensive, obviously, but they do last a longer than the 4-inch ones. I almost always leave a cutting disc in my 5-inch grinder and leave the 4-inch grinders for other duties.


Purchase a cheap 4-inch grinder first. If you choose to purchase a second grinder, consider a 5-inch grinder if cutting tube is a common task.


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