A bench grinder is a power tool that is designed to sit on a benchtop, allowing easy access for sharpening cutting tools, including tool bits, drill bits, gouges and chisels. These machines are widely used in metal fabrication to sharpen tools or roughly shape metals prior to welding or fitting, this all depends on the bond and grade of the grinding wheel.
Bench grinders work by spinning grindstones and then running a dull tool or blade against it, effectively sharpening the tool. You can find grindstone wheels with different levels of coarseness, but generally those who use bench grinders tend to prefer coarser wheels (usually darker in colour), in order to quickly and easily remove material.
They can also be used for shaping or polishing wood, however the right grinding wheel is required for this work.
One thing you need to be mindful of when using a bench grinder is heat generation. Make sure not to overheat the metal, as it may soften the tool and render it useless. To avoid this, when sharpening a tool, apply light pressure and dip it into water every now and then to cool it down.
Most bench grinders run at about 3,450 rpm, unless they are variable speed. If your bench grinder will be used primarily for sharpening tools, a lower-speed grinder may be your best bet. This is because the lower speed reduces the risk of overheating the tool.
If you're looking for a bench grinder that can do a few things, look for one that comes with additional attachments, such as sanders, polishing wheels and linishers. Otherwise, you can pick up these attachments and accessories elsewhere, usually they are inexpensive.
To keep your grinder wheel in top shape, you'll need to dress it to expose new grit for greater cutting efficiency.
Some of the most popular bench grinder manufacturers include Hafco Metalmaster, Jones & Shipman, Ajax and Okamoto. If you're not sure which grinder is best for your specific project needs, then make sure you speak to your local dealer or bench grinder seller.
