As power tools go, angle grinders are pretty basic. Taking their name from how they look, angle grinders consist of a tool head with a rotating disc that sits at a 90-degree angle from the shaft of the tool. However when it comes to what they can do, angle grinders (aka disc grinder or side grinder) are anything but basic.
Want to cut a metal pipe or the head off a rusted bolt? You need an angle grinder.Want to cut tiles, stone or concrete? Angle grinder once again. But there is so much more angle grinders can do. Like grinding out old grout between tiles; removing rust or paint from metal; sharpening blades and even polishing off caked-on grime from the bottom of your gran’s treasured set of 20-year-old pots and pans.
As with any power tool purchase price is the last thing you should look at. The first thing you should ask is: “What do I need it for and how will I use it?” The angle grinder you’d pick for regular, heavy-use industrial application is not the same as the one you’d pick for your DIY toolkit. Let’s explore the key things you need to think of when choosing the right angle grinder for you.
#1: Disc size
When it comes to angle grinders, size does indeed matter. In fact, it’s your primary consideration. Angle grinders are classed according to the size of the disc (aka blade or wheel) they are designed for, with 4½” (115mm), 5” (125mm) and 9” (230mm) being the most common. For normal household DIY applications like cutting tiles and thinnish metal, grinding, sanding and buffing, 115 and 125mm angle grinders are perfect. These angle grinders are lightweight, easy to handle and deliver some finesse. However their smaller size does of course mean that they are unsuitable for cutting very deep or large objects.
If massive concrete slabs are what you intend to tackle, a larger 230mm angle grinder is what you need. Bear in mind that the larger the disc, the more power the angle grinder needs and the heavier it is.
There are numerous different discs for angle grinders, suited to different tasks. A grinding disc is the one to turn to for smoothing any kind of metal. Cutting discs, as the name suggests, are for cutting applications, with diamond cutting discs especially suited to tough cutting jobs. Other options include sanding discs; poly-fibre strip discs for gently removing paint, glue and epoxy from metal surfaces as well as wire discs for heavy work like rust removal.
#2: Power source
Like most power tools, angle grinders are available corded or cordless. Corded grinders typically generate more power and deliver it at a constant level. The drawback is that you’re tied to a physical location and, if you’re working outside, have to deal with the hassle of extension cords. Cordless angle grinders give you greater freedom of movement for outside work and work in tight spaces. They tend to have less power, but if you’re choosing a DIY-sized 115mm or 125mm model, this is not much of a factor. Just make sure the model you pick comes with a high-performance battery and ideally have a second battery on standby.
Angle grinder speed is measured in RPM (revolutions per minute) with most grinders in the 5 000 to 10 000 RPM range. The higher the speed, the more powerful the angle grinder is and the quicker you can cut through material. Do remember though that cutting discs are designed to be compatible with certain speeds. Pop a disc rated to run at 5 000 RPM into a 10 000 RPM angle grinder and you’re asking for a whole bunch of trouble, with the disc potentially shattering and sending shards flying.
#4: Hand guard
Hand guards on angle grinders are either fixed or moveable. If you are right handed, this is not much of a consideration. If you’re a leftie, a model with a moveable hand guard may be the better choice for you.
Points 1-4 cover the big things to look out for in making your angle grinder choice. But it’s also useful to consider the following:
- Restart protection: Should the power source be interrupted and then come on again, an angle grinder without restart protection will immediately start up, and this is potentially a major safety concern. Models with restart protection require you to physically turn the angle grinder off and on again if power has been interrupted.
- Soft-start motor: Angle grinders are immensely powerful tools and probably the cause of a fair amount of power tool injuries. Turn an angle grinder on and it’s like instantly having a bad-tempered bucking horse in your hands. Models fitted with a soft-start motor allow the speed to gradually build up, giving the user time to adjust to all that power. If you’re a novice or infrequent user and just not used holding an angle grinder this feature is particularly useful.
- Brakes: The disc on an angle grinder keeps on turning at high speed for some time after you’ve disengaged the switch. This is annoying because you have to wait for it to stop before you can put it down. It’s also potentially dangerous. Increasingly manufacturers are starting to fit angle grinders with rapid-stop brakes, especially on the higher end models.
While we’re on the subject of safety, remember to always wear PPE when working with an angle grinder. The words PPE and masks may be something we’re all pretty tired of at the end of this extraordinary year, but do think of:
I hope this has been useful in helping you pick the right angle grinder for the job. Remember to stay in touch with all our latest news and tips by following us on Facebook and Instagram. And don’t forget to sign up for our monthly specials.
Bosch Angle grinder (GWS 700)
R 1,285.00 R 2,250.00
Makita Angle grinder (GA9020K)
R 3,465.00 R 4,050.00
Ryobi Angle grinder (G-915)
R 625.00 R 720.00
Cordless Ryobi Angle grinder (XG-115)
R 1,015.00 R 1,095.00
Makita Angle grinder (G9557HNG)
R 1,245.00 R 1,750.00