If you’re going to keep your cutting tools working properly, then you need to have a sharpening tool as part of your tool-set. A grinder is one of the best sharpening tools as it is easy to use and very effective too.
Bench grinders differ in size, use, type of grit used, type of wheel used, and so on. Today, we will delve into the main types available so that when you go shopping for a bench grinder, you’re able to make an informed decision.
Let’s walk together.
Types of Bench Grinders Based on General Design
1. Woodworking bench grinder
This grinder is designed majorly for smoothing the dull cutting edges, but they can also be used for grinding wood.
Working on a project that needs a high degree of precision? The woodworking bench grinder runs at a low speed, and as such, it is perfect for precise grinding.
2. Automotive bench grinder
Don’t let the name confuse you. The automotive bench grinder is not designated for use in the automotive industry. Actually, it is used for grinding a whole range of cutting tools as well as shaping various metal equipment.
As the grinder is very stable and doesn’t need much adjustment before use, it is quite popular.
3. Standard variable speed grinder
We figured we’d save the best for last. If you have many tasks or just need something professional; something that will handle everything you throw at it; something that will serve you excellently for a long time, then the standard variable speed grinder is what you got to get.
You can use all sorts of grinding wheels on this one, and for that, you can use the grinder for virtually any job.
With this bench grinder, it is possible to set the precision as you like, since you can adjust the speed. Lower speed equals higher precision.
4. Portable grinder
As the name suggests, this bench grinder is lightweight and movable from place to place.
In case you’re working at a site and have to adjust tools quickly from time to time, a portable grinder will be most useful.
The drawback? They’re not as strong as the bigger grinders and might not be very helpful when it comes to adjusting tough metals like steel.
Read Also: Difference Between bench-grinder and belt-sander
Bench Grinder Types Based on the Wheel
While the wheel is a part of the bench grinder, it is the one that does all the work, and as such, it’s an aspect that can be used to classify bench grinders. There are different wheel varieties, including fine wheels, course wheels, tapered wheels, straight wheels, and so on.
To choose the grinder that works for you based on the wheel, you need to ensure the rated speed works for you, keeping in mind that harder tasks require higher speeds.
1. Straight Wheel Grinder
This is the most common wheel, being used mostly for sharpening chisels and similar tools. The straight wheel grinder is used for:
- Any surface grinding
- Cylindrical and centerless grinding
2. Tapered wheel grinder
This grinder has its wheel narrowing towards to edges, and because of this design, it is ideal for delicate works like sharpening the gear teeth or grinding threads. As the edges are tapered, getting into the grooves becomes much easier.
3. Saucer wheel grinder
Do you work with many saw blades and you’re looking for a grinder that can sharpen them efficiently? A saucer wheel grinder is what you need.
4. Cylinder wheel grinder
If you got a huge metal sheet that you want to sharpen all at once, then you will find a cylinder wheel grinder most useful. The wheel is normally hollow and huge to suit huge materials.
5. Diamond wheel grinder
This one is for when you need to work on materials that are really hard. The wheel is normally lined with diamond bits, and as diamond is one of the hardest elements on earth, the grinder is capable of sharpening just about anything.
Bench Grinder Types Based on The Grit
1. Silicon carbide grit grinders
These normally come in green and black colors, and they’re normally used for finishing.
Green happens to be sharper than black, and it is used to sharpen plasma-sprayed materials and tough metal objects like titanium.
Black is used for sharpening softer metal objects (like aluminum) as well as plastics and stones.
2. Aluminum oxide grit grinder
Aluminum oxide happens to be the most common grit for grinders with brown and gray being the most common colors due to their inexpensive yet efficient nature. And yes, the color affects efficiency at getting the work done.
Gray and brown aluminum oxide grits are multi-purpose, suited for both high and low carbon steel.
There are also colors white and pink, which are suited for harder objects to prevent overheating but these are a bit more expensive than the brown and gray grits.
Ruby red is tougher than the others and can be used to sharpen the toughest objects, and for that, this grit is virtually the most expensive.
3. Ceramic grit grinders
This is one of the recent inventions, and it comes with a very interesting feature. You know the way grits dull as they’re used?
This works the opposite way with the ceramic grit. Rather than dulling, the grit becomes sharper the more it is used. That’s great for saving money and time.
On the flipside, however, these grits are quite expensive.
A note on grit types
Apart from the grit types we’ve talked about above, grinders can also be categorized according to the size of the grits. In that regard, there are 4 main types of grinders namely:
- Coarse grit – 16 to 24
- List Fine grit – 80 to 120
- Superfine grit – 150 and above
- Medium grit – 36 to 60
Remember, the greater the coarseness, the faster the speed with which material is removed. Nonetheless, a coarser grit leaves behind a rougher surface.
If you’re only dealing with slight dullness, or perhaps a few tiny dents on your cutting tools, it’d be better to use a finer grit grinder.
Frequently Asked Questions (FAQs)
1. Who invented the grinder?
The grinder was developed in the 1900s, and was generally attributed to the Ball & Bearing Roller Company, and particularly to Lewis Heim, an engineer who worked for the firm.
2. What is a bench grinder wheel made of?
The wheel is made of abrasive grain. The abrasiveness of the grain is different on different wheels, so be sure to select what suits the material you’re looking to grind.
3. What is the bench grinder used for?
A bench grinder is a benchtop machine that drives abrasive wheels. Many folks use it to sharpen dull cutting tools like knives, chisels, and drill bits but the machine can also be used for shaping metal before it is welded or fitted.
You can also use the bench grinder for polishing or cleaning virtually all metal objects.
4. Is it possible to use a bench grinder to grind wood?
Yes, of course. The abrasive surface works just like sandpaper or another abrasive used for grinding wooden objects. However, you need to choose the right grit size and the right speed while grinding wood. Finer grits would work better for polishing wood. The woodworking bench grinder would be the best option for grinding wooden items.
5. Can I use a bench grinder to grind aluminum?
Yes. Nonetheless, you need to exercise caution. Realize that aluminum is a soft metal and at high temperatures, it melts more easily than other metals. As the grinding action produces lots of heat, it’s possible that the aluminum will melt, and some of the metal will coat the wheel.
To prevent that from happening, cool down the metal several times through the sharpening exercise. Have a bucket of water nearby and after a few seconds, dip it in the water and wipe it dry with a towel before progressing.