Also known as disc or side grinders, angle grinders are portable tools designed for polishing and grinding. They’re commonly used in a wide range of industries, including construction, metalworking, emergency rescue and more. Angle grinders can be powered with an electric motor, compressed air or a petrol engine. Handheld angle grinders are the most commonly used type for most practical applications. The discs that angle grinders use have a direct bearing on your choice of a grinder.
The two most common disc sizes are 115mm and 230mm, anything bigger than that is meant for heavy-duty applications, whereas anything smaller than that is for finer work. Further, worth noting is that smaller grinders have a higher RPM, but their discs are more prone to wear. Besides size, the power source, RPM, arbour size and motor power should also be considered when shopping for an angle grinder.
There are three types of angle grinders based on how they’re powered, each suitable for a specific purpose. Understanding the difference between all three types is crucial for making a well-informed buying decision.
Also known as cordless grinders, these devices are very practical and used across many industries. Battery powered grinders can be transported to different areas, and they can work without a mains source. Cordless angle grinders are particularly useful in situations when you need to climb a ladder or scaffold since there’s no risk of tripping over some trailing wires. However, you should choose a model with high capacity batteries to avoid having to recharge them in the middle of grinding. Alternatively, you can get an extra pack of batteries and charge one of the packs when using the other.
Corded angle grinders, while not as portable as their cordless counterparts, provide continuous operation since they’re hooked up to a power supply. So if you’re always going to have a power supply nearby, and you’re going to use the grinder for extended periods of time, a corded angle will work best for you. If you’re mainly going to perform minor cutting jobs, consider getting a smaller model that’s more ergonomic and has a small disc. Additionally, consider the vibration dampening properties of the grinder you choose.
Pneumatic grinders offer a great mixture of performance and durability, making them ideal for cutting and shaping metal. They’re mainly used for light-duty tasks that require a lot of precision. Pneumatic grinders require compressed air to operate and are the most lightweight out of all types since they don’t have an electric motor. Some pneumatic grinders come with throttle levers, allowing for a higher level of control when performing technical tasks like speed grinding or feather edging.
The power of an angle grinder depends on the wattage. The required wattage will depend on the size of the disc. The input power of corded models is rated in amps, whereas cordless grinders are rated in volts. The input of pneumatic grinders is rated in cubic feet per minute, and there’s usually a corresponding PSI (pressure in pounds per square inch).
Angle grinders usually come with a range of safety features to prevent injuries. A slow start is one of them, which prevents the grinder from twisting immediately after starting. Anti-kickback is another feature that comes in handy, ensuring the motor cuts out if the grinder gets caught up on any material. Restart protection ensures the grinder stays off in case it gets overheated or cut out and left with the power on. A deadman’s switch, or the paddle, ensures the grinder only operates when held with both hands and prevents spinning should the switch be released.
There are also a couple of safety procedures that should be followed when using grinders. For starters, you should always wear the necessary personal protective equipment (PPE), which includes ear defenders, dust mask, gloves and safety goggles. The protective equipment will act as a safeguard against sparks that fly up when using a grinder. You should also look to minimise the risk of your clothes catching fire when grinding by wearing flame retardant clothing.
Before you start using an angle grinder, you should alert everyone present and organise the wiring in order to prevent electrical hazards. The disc on the grinder should be static before positioning it to the surface to ensure it doesn’t spin and cause damages. Other safety procedures you should follow include: