Do you have a metal roof that is corroding? Then remove that rust with an angle grinder! Have an old door that is in desperate need of a new coat of paint? Strip off the old paint easily - with an angle grinder! Need to cut through concrete? Use an angle grinder!
The angle grinder is a useful, versatile hand held power tool. This buyers guide gives some advice on how to use an angle grinder and features you should look out for if you want to buy a new angle grinder.
What Should You Use an Angle Grinder For?
By fitting different attachments or wheels, an angle grinder can be used to cut, sand, polish and sharpen various materials.
Cutting - Various cutting discs can be used with angle grinders making them useful for cutting through stone, metal or concrete. Diamond tipped edges are the strongest of discs. Ideal users would be General Contractors, Auto-body repair and Plumbers.
Sanding - With a sanding pad attached, an angle grinder can become a very effective sanding machine on wood materials (handy for stripping old paint). The best results are achieved by using the proper grit abrasive. As a rule, you will want to start with more coarse grinding or sanding grits for removing large defects or rough spots, then work through finer grits until you achieve the smoothness and quality you want. However, for items that require a delicate touch, you should use an angle grinder with a variable speed control. Although a grinder is not considered a "woodworking" tool, that's not to say it cannot perform woodworking tasks.
Polishing - With the right disc fitted, angle grinders can be used to buff up metal. You can fit your angle grinder with wire brushes for rust and corrosion removal. Auto-Body Repair shops and Metal Fabrication Shops uses grinders daily.
Sharpening - Many people use their angle grinder to sharpen old tools and lawnmower blades. However, this can be tricky so we recommend you leave sharpening to the experts.
Grinding - The most common task for this tool is grinding metal weld seams to a smooth flat seamless finish. Anyone who uses a welder will commonly have a small angle grinder in their tool arsenal with a wide array of different grinding wheels. You can also grind down concrete and stone, so this tool fits nicely in a Stone Masons tool bag as well.
Makita Grinder Features to Consider -
Variable Speed - A Variable Speed dial that enables the user to match the speed to the application needed.
No Lock On - Some users prefer to have a "no lock on" feature.
Soft Start - Slow start up of the wheel to allow for smooth start-ups, will gradually come to full speed. This also prevents the tool from wrenching or twisting on start up.
Note, that you must wait for the motor to obtain full speed before applying the disc to the work
Electronic Speed Control - Any time a grinder is put under a load of the application, the grinder slows down. This producs a corresponding reduction in the work done and if abused, produces a significant amount of heat and possible tool failure. As pressure is applied to the material, the speed control allows additonal amperage to boost the speed up to the required or rated level of the grinder.
Lock Off - Some users prefer a grinder with a "lock Off". With this feature, there is a small tab on the paddle that is pulled in order to activete the paddle switch.
Lock On - A grinder that has a lock-on feature allows for it to be locked on in the ON position. This feature will have either a slide switch, a button next to the trigger switch or a button below the paddle switch.
SJS (Super Joint System) - SJS is where the motor armature and spiral bevel gear are linked by a coil spring. If the grinding wheel catches or binds - the coil spring relaxes and disengages the gears from the motor, it works similar to a clutch. helps to protect the motor and gears.
Key Features to Look For when Purchasing an Angle Grinder
No Load Speed - The speed the disc rotates at before cutting starts. Most manufacturers list their speed ratings based off of no-load pressure. Some of the benefits of using slow speed grinders (as compared to those with faster speeds) is that they are generally quieter to operate than regular grinders. Also, you don't produce as much heat (that can be destructive to tools) with the slow speed grinders. One drawback of using slow speed grinders is that many people believe they don't provide enough heat compared with the higher speed grinders. If you are concerned about this, you should consider getting a variable control grinder so you can adjust the level of heat you're getting. Different materials require different speeds for optimal results. As a general rule, use low settings of around 2000 RMP for burnishing metals and high speeds in the region of 5000 to 7000 for cutting hard materials
Voltage - 240volt, 110volt or 18volt re-chargeable, a cordless tool offers more flexibility. The higher the Cordless Voltage, the more powerfull the grinder
Wattage - Larger discs require more power
Spindle Lock - Makes disc and accessory changes quicker and easier
Disc Size - The most common disc sizes available are 4-1/2 inch (115mm), 5 inch (125mm) 6 inch (150mm), 7 inch (180mm), 9 inch (230mm). Larger Sizes are better for larger surfaces and bigger depth of cuts. Small angle grinders range from 4-1/2 to 6-in, while large angle grinders are 7 to 9-in
Adjustable Guard - This will protect you from sparks and debris and can be moved to suit the current job.
Adjustable Side Handle - This makes the machine useable either right or left handed. The more positions available, the more versatile the machine is.
Anti-Vibration Handle - This will make the machine more comfortable to use over extended periods and to help reduce fatigue and enhance control and maneuverability.
Wheel Types and Uses