10 Best Bench Grinders | March 2017
- coolant tray for use with metal
- magnifier in the safety shields
- mid-grade tool guides
- cast iron motor housing
- precision-machined tool rests
- excessive vibration from 36 grit
- rubber feet reduce vibrations
- mounting holes for simple setup
- flexible tool rests are flimsy
- patented bit sharpening attachment
- water cooling tray
- frustrating bolt hole spacing
- protective cover bayonet lock
- maintenance-free induction motor
- spark protection glasses
- two-piece tool rest
- vertical and horizontal adjustments
- 36 grit wheel included
- pre-lubricated ball bearings
- cast-iron wheel guards
- motor designed for heavy daily use
What Is A Bench Grinder?
A bench grinder is a portable version of larger, industrial grade grinding machines found in many machinist and metal working shops. They spin at high speeds to remove material, which can be anything from wood to metal, by abrasion. Since they are using abrasion, there is a lot of friction and they generally produce a lot of heat. Because of this, you may see operators using gloves when using one, especially if working with highly conductive metals.
Most bench grinders have two wheels with varying grain sizes. This allows one to be used for removal of a large amount of material, while the other can be used for smooth finishing work. Grinding wheels can be made from a variety of materials, with each type being best suited for a certain type of application. The most commonly seen grinding wheels are made from either silicone carbide or aluminum oxide. Bench grinders also allow for the installation of fiber and wire wheels designed buffing and polishing.
Since bench grinders are relatively small and lightweight, it is often necessary to mount them to a table or bench of some kind, hence the name bench grinders. Otherwise the vibrations may cause them to move around while you work. They are usually mounted by bolting them to a surface through pre-drilled holes in the base.
How and what you use a bench grinder for will depend on the size, grain, and type of wheel you have installed. Some of the most common uses include sharpening blades and metal hand tools, rough shaping metal work, and roughing up metal surfaces before welding. They can also be used for removing burrs and casting, or polishing and buffing items.
Choosing The Right Bench Grinder
There are four main things you should consider when picking the right bench grinder for you: power, precision, durability, and cost. Buying one that is cheap, but breaks after a couple of uses is just as much of a waste of money as buying one incredibly overpowered for your needs.
First ask yourself what you will be using the bench grinder for the majority of the time. If you plan on grinding tough metals or need to grind large areas quickly, one with a bigger motor will be a good bet. The larger the motor, the more power your grinder will have and the quicker you'll be able to get the job done.
If you are new to using a bench grinder, you may feel more comfortable with a slow speed model as there is less chance of over-grinding an object. They also make models with dual speed options or adjustable speed controls. These kinds are usually more expensive, but can be invaluable to a beginner or somebody who often works on different kinds of materials.
Since bench grinders operate at high speeds and you put strain on them as you grind down materials, it is important to buy one from a well known company that makes quality tools like DeWALT, JET, or Metabo. If you go with a low-quality China-made model that costs considerably less, you may find that the motor burns out after just a few months.
Wheel size plays a big factor in how you can use your bench grinder and how quickly it gets the job done. For home workshop use, bench grinder wheels range in size from 3 to 8 inches. Ideally it's best to go with one between 6 and 8 inches unless you know you will only be using it on very small objects that don't need heavy grinding.
Other features you may want in a bench grinder include an integrated work light, an adjustable tool rest, adjustable eye guards, a soft start function, and a vibration resistant base. These will help you safely use a bench grinder.
Choosing The Right Grinding Wheel
After finding the best bench grinder for your needs, you'll need to be sure to purchase the right type and grit wheel. Understanding all the differences between grinding wheels can get very confusing, but luckily you don't need to know everything. There are a few things that anybody picking a grinding wheel needs to know though.
First is what type of wheel material is right for the job you are doing. A silicone carbide blade is highly abrasive and ideal for working with stone, brass, and aluminum. An aluminum oxide wheel is best for grinding steel, steel alloys, and other ferrous metals. They can also be used for woodworking or other softer materials that might crumble if you put too much pressure on them while grinding.
The next thing to understand is grit size. Bench grinding wheels generally range from 16 to 120 grit, with the higher the number, the finer the grit. They are often labeled as coarse (16 to 24 grit), medium (36 to 60 grit), and fine (80 to 120 grit). If you want to remove a lot of material quickly and the worked object can be left with a rough finish, use a coarse grit wheel. If you need to work slowly and precisely and want a smooth almost polished finish, go with a fine grit wheel.