May 3, 2021

How to Sharpen Chisels on a Bench Grinder

Bench grinders are tool sharpening stations that are available at most hardware stores. They sharpen chisels and saw blades with ease and quickness, making them one of the most popular choices in woodworking shops. The following article will outline how to use a bench grinder to sharpen chisels like a pro – step-by-step instructions and everything.

First of all, let’s examine the tools needed to sharpen chisels on a bench grinder:

  • A bench grinder
  • A premium grinding wheel
  • An emery wheel
  • A face shield
  • Eye protection
  • Gloves.

I recommend a 40-grit aluminum oxide wheel for the grinding process and an 80 grit silicon carbide wheel for this particular project’s finishing process.

The grinding wheel is inserted in the chuck and rotated. The grinding wheel rotates at a slow speed, so the end mill does not have to move much.

Once the grinder is warmed up, start turning on the motor and adjust the speed control to grind away.

Insert your chisel in front of the grinding wheel and hold it steady by placing my left hand on it near its top.

Begin grinding with the right hand, applying pressure to keep the chisel from moving. Move the chisel up and down to create a tiny radius along the edge of the blade.

After completing both sides of the chisel, please remove it from in front of the grinding wheel and turn off the grinder. Then, use a piece of emery cloth on an emery wheel to sharpen both sides of my chisel’s edge again.

At this point, repeat the same process with the following grinding wheel size. For example, continue to use the 40-grit aluminum oxide grinding wheel for all the chisels that are smaller than 20mm. This means you will have to take off the 40-grit wheel and replace it with an 80-grit silicon carbide wheel.

When you begin using the 80-grit wheel, slowly adjust your hand pressure on the chisel to be lighter. This will allow the grinding wheel to start doing more of the work.

Hold your chisel in front of the grinding wheel and continue moving it up and down – only a few millimeters each way – for about 16 revolutions. Repeat this process with the other side of the chisel.

After completing both sides of the chisel, please remove it from in front of the grinding wheel and turn off the grinder. Then, use a piece of emery cloth on an emery wheel to sharpen both sides of my chisel’s edge again.

At this point, my chisels are ready to be used in woodworking projects and cut through materials like butter.

As you can see, sharpening chisels on a bench grinder is simple. The most important thing is to wear the appropriate safety gear and follow these simple steps.

Safety Instructions

  1. Wear safety goggles at all times when using any grinding wheel.
  2. Make sure that the grinding machine is unplugged before touching it and before inserting or removing wheels, grinding belts, or discs.
  3. Always use a face shield, long pants, long-sleeved shirts, and gloves. Never touch your face or eyes with dirty hands to avoid eye injuries from flying debris.
  4. Turn off the machine before disconnecting a wheel, grinding belt, or disc.
  5. Adjust the grinding wheel to the proper speed for grinding wheels according to the manufacturers’ recommendations.
  6. When changing from one type of wheel to another, remove all dust and debris before making the switch. This ensures that no contaminants are left on the machine and that you avoid injury when touching it while it is in operation.

Cleaning the chisel

  1. When finished, remove the wheels or discs and clean the grinding machine using a mild soap solution and a damp cloth.
  2. Immediately wipe down all work surfaces using a damp cloth to prevent dirt from becoming embedded in them.
  3. Wash your hands with soap and water after working with abrasive materials to avoid contaminating food, drink, or any other sensitive items that you may touch in the future.

Sharpening tips

  1. Before using the grinding wheel, make sure that it is not damaged. Check it for cracks, chips, peeling paint, or any other wear and tear signs to avoid serious injury. If you notice any damage to the wheel when you first open the package, contact the wheel manufacturer and ask them to replace it for you before using it to avoid injury to your hand while using it.
  2. Always wear safety gear such as goggles and gloves when grinding wheels on a bench grinder. If you are wearing gloves, make sure they fit tightly and do not slip off your hand.
  3. When using a grinding wheel, make sure your body is at least 30 centimeters away from the wheel to avoid injury from being cut by the abrasive material while working with it. This is especially important when using the grinding wheel in an enclosed area like a shop or basement.
  4. When you work with grinding wheels on a bench grinder, hold your chisel at a 45-degree angle to the grinding wheel to avoid injury from being cut by the abrasive material.
  5. The angle of your chisel should be no more than 30 degrees to the grinding wheel. Too much of an angle can put more force on your hand and cause it to hurt; too little of an angle can lead you to believe that it does not need any more sharpening when it does.
  6. The amount of force you put on the grinding wheel depends on what type and size of chisel you are sharpening. To be safe, I put no more than about 50% of my chisels’ total weight on the grinding wheel at a time to avoid injury. Your mileage may vary depending on what type of grind wheel you have and how much force you apply to it.
  7. Never use a grinding wheel with an abrasive material that is not intended for it while sharpening your chisels for safety reasons.
  8. When using a grinding wheel, make sure you are using the correct grit for the type and size of chisel you are sharpening. The grit size on the grinding wheel is usually stamped on it somewhere that can be seen with your eyes, but more often, it will be written directly on its surface in a word or two.

Setting up the grinder

  1. Choose a bench grinder manufactured by a reputable company, preferably one that manufactures power tools. Bench grinders are made to grind metal and not wood, so choose one designed to work with metal exclusively. Using a non-metal grinder can be hazardous to your health and cause severe injury or death since companies do not know what they are doing when manufacturing them.
  2. Set up the grinding wheel entirely before starting it for safety reasons. Make sure that it turns both clockwise and counterclockwise without any problems or rough spots. Set the proper amount of weight to match the job at hand, determined by the size and type of chisel you are sharpening.
  3. Make sure your chisels are clean before using a grinding wheel for safety reasons.
  4. You must use goggles or safety glasses when using a grinding wheel for safety reasons.
  5. Once the grinding wheel starts moving, make sure that it does not make any abnormal sounds for safety reasons. If it does, shut it off immediately and scrutinize the problem so that you can avoid injury or death. Never try to fix the problem without first removing your hands from the work area because a workpiece can fall off of the grinding wheel at any time during its operation while doing this job.
  6. You can use a grinding wheel for sharpening your chisels by holding the chisel’s handle in the palm of your hand and then grasping the base of the blade with your fingers. This allows you to hold it firmly while letting it rest on the grinding wheel at an angle. While doing this, you must keep slight forward pressure on the chisel blade while letting gravity do most of the work.
  7. While the chisel is being sharpened on the grinding wheel, you must frequently change the chisel blade’s angle to a vertical position while it rests momentarily on one side of the grinding wheel. You can then remove some of the work-hardened surfaces by hitting with a ball-point hammer. This will help flatten and straighten out the hardened surface as well.

Sharpening the chisel

For some fine chisels, the bevel may have to be ground down at an angle. This is done in the same way as the grinding of steel. You can either use a sharpening stone or a file to reduce the bevel and make it a right angle. Before you start work on your chisel, always hold it by the handle to not damage its blade edge with your chisel.

This work is all done in one direction – counterclockwise. A grinding stone, file, or straight edge grind the bevel backward (in the same direction that the chisel blade was ground) at an angle. You may have to remove a little material from each side of the chisel and use a fresh piece of wheeling material for each side before proceeding with this step.

Now that all your sharpening tools are in place, it’s time to sharpen the chisel. This is done after grinding the chisel and is a relatively straightforward process if you know-how. If you only have one chisel to sharpen, there is no reason to buy a special fixture. One way to do this is to clamp the chisel to the edge of your bench, or table saw fence, or a piece of wood clamped securely in place.

Test the sharpness of the chisels

After sharpening the blades, you must test them. You will do this by touching the chisel on a steel edge or piece of scrap metal. It should cut through easily and smoothly without you having to exert much pressure on it. You can use a steel file to make sure of this.

You can also try resting your chisels against each other to see if they both cut at the same angle. Rest them about 1/8 or 3/16 inches apart. You should find that both will cut through metal without much effort and precisely at the same angle.

Clean up the work area

When you are finished working with the grinding wheel, clean it up immediately to avoid spending extra time doing this task later. This cleaning is done with a cloth dampened in some mild soap.

References

https://www.woodcentral.com/article/sharpening-chisels-a-bench-grinder
https://www.reference.com/household/grinding-wheel-4c7bba107c3312b8
http://www.digikey.com/product-certificates/grinding-wheels/60-59278435
http://www.sherline.com/product_info.php?products_id=1156
http://www.safetyresourcecenter.com/index.cfm?fa=content&ctg=RCPart2&node_id=406
http://www.toolstoponline.co.uk/pdf/Bench_Grinders_Comparison.pdf

See our CNC Machine Turning Tips

David D. Hughes
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