Chisels are crucial for a variety of applications, and keeping them sharp is essential. Although traditional methods exist, sharpening a chisel with an angle grinder is the fastest and most handy solution. This is best suited when there are not many tools around, and you want to sharpen the chisel to a fine point. So, how to sharpen a chisel with an angle grinder?
The process itself is easy and requires a substantial perception of angle and also depends upon the chisel’s state. The main focus is to maintain the angle’s consistency and develop a fine bevel without ruining the blade’s temper. This would allow it to hold the edge longer.
6 Steps to Sharpen a Chisel with an Angle Grinder
- Sandpaper of 80 or 150 or 220 grit
- Protective eyewear
- 6″ angle grinder
- Angle grinder stand
- A tumbler of cold/room temperature water
- Oil stone(optional)
Step 1: Inspection
This step is crucial as it pertains to inspecting the state of the chisel. If it is relatively new, or the bevel and edge are in better shape, a simple repetition of sharpening using sandpaper would do.
However, if the end of the chisel is nicked or rounded over, the angle grinder is indispensable. The angle grinder will help in removing the required amount of metal and re-establishing the bevel.
Step 2: Preparing
In order to prepare efficiently, glue the sandpaper to a flat block of wood or thick glass. Although the sandpaper would be utilized later, it is essential to let the glue dry off. If you use a thick glass piece as the flat surface, stick the sandpaper to both sides to avoid sliding off.
Next, to maintain uniformity, ascertain a level to which you will remove the metal of the chisel. Use a marker to draw an ‘end’ line across the back of your chisel. This will help indicate up to what level the metal has to be removed.
Step 3: Sharpening
Before you begin with this step, keep the tumbler of water close. This is essential, as the angle grinder’s disc spins at a very high speed.
The excessive heat generated can burn the edge of your chisel. This would render the tool useless and unproductive. Thus, to avoid overheating, quench the chisel often to maintain the temper.
To begin, ensure the angle grinder’s disc should turn away from the edge. This would also prevent sparks from coming towards your face.
In the first contact or swipe, completely flatten the front edge of the chisel against the grinder’s disc. Guarantee minimal pressure exertion. This helps in removing the nicked/rounded portion of the metal.
It is imperative to dunk the chisel in the tumbler every four seconds or so. If this step of removing the nicked portion is longer, then keeping the chisel cool is absolutely important.
If extra pressure is applied or the chisel is swiped for a longer duration, a slight blue or straw color develops at the edge.
This signifies that the edge has been ‘cooked’ and the temper is ruined. The only remedial measure is to keep grinding the chisel against the disc until the soft, blue steel portion is removed.
Keeping the chisel cool is the most important measure while using a chisel grinder sharpener.
Step 4: Bevel Creation
This step involves creating the bevel. Here, the angle at which the chisel is placed against the disc and pressure applied have an important bearing.
Before beginning, place the chisel against the stationary disc and ensure that it is placed at an angle of 25° to 30°.
This helps you maintain the constant angle as you will have a perception of the same from the beginning. Alternatively, you can position the disc accordingly to match the blade’s bevel.
If you are angling and moving the chisel blade while holding the angle grinder fixed, maintain the angle of the blade. Keep the pressure apt, slightly more than the previous step.
Dunk the blade often in the tumbler. Keep the blade moving, maintaining a periodic back and forth motion. It is vital not to apply excessive pressure; else, the back-forth movement would backfire.
If you are holding the chisel blade fixed, and angling the grinder’s disc, adhere to the same in the aforementioned case. Here, maintain the grinder at the required angle and move it towards the direction of the handle.
Avoid back-forth movement, and continually lift off the disc and begin from the edge again. In this case, the blade would need to be dunk more frequently. Do not let the disc rest at any point.
It is best to move the chisel while steadily holding the grinder with the other hand. It is faster and handy. An appropriate vise can also be used to control the grinder at a specific angle for creating the bevel. You can use a suitable angle grinder stand to hold the grinder firmly.
Step 5: The Other Side
After a few swipes of grinding, inspect the chisel’s edge. It need not be perfectly square, but it must be straight. If it is uneven, adjust the angle a bit more and grind a little until a straight chisel edge is obtained.
Now, at the back of the chisel, on the flat surface side, you would notice an uneven surface. This is due to the aggressive speed of the angle grinder’s disc.
On one side, the bevel has been made and sharpened. Now, the flat side of the chisel should be tended. It provides the necessary finishing and further sharpens the bevel, as both sides of the chisel blade are flat and smooth.
Step 6: Finishing Touches
Finally, use the 150 or 220 grit sandpaper to add the finishing. Hold the back of the blade flat, press hard, and rub it diagonally against the sandpaper to smoothen it entirely. This gives a finer and thinner dimension to the chisel’s edge.
After a good amount of rubbing, feel against the flat side of the blade. If you feel slight accumulation or elevation of metal, it signifies that the rubbing has been done adequately.
Remove the accumulation with further rubbing, and a sharp chisel with a sharp and new-like edge is ready.
These steps pave the best way to sharpen a chisel with an angle grinder.
Tools That Can Be Sharpened With an Angle Grinder
An angle grinder is dynamic in use and application. A chisel is not the only tool that can be sharpened with the machine. Heavy tools like hoes, shovels, hatchets, axes, lawnmower blades, and other hosts of bladed tools can be sharpened.
The main focus is to correctly angle the grinder to the respective blade of the tool. Keep the disc moving towards a specific direction, and avoid back-forth in heavy bladed tools too.
Keep the angle consistent ( about around 25° for all bladed tools), and apply required pressure, with adjustments in both as and when needed. In the case of shovels, axes, and hatchets, their blade’s material is different and takes longer to heat.
Nevertheless, keep a container of water handy to avoid any wastage through overheating material. The angle grinder can also be used to remove worn layers of material off the blade and renew the edge.
Angle grinders with adjustable speeds can be used to sharpen ice scrapers minutely.
1. How often do you need to sharpen a chisel?
A chisel is a woodworking tool, and it must be sharpened at least once in a span of 2-3 hours.
However, it also depends upon the chisel’s material quality and a load of work on it. The density/hardness of the surface also affects the routine sharpening.
2. How can you tell if a chisel is sharp?
A sharp chisel will easily shave off the hair on the arms with minimal pressure and contact. When subjected to bright light, no visible reflection will be noticed off a sharp chisel.
Slice a paper with the chisel; a sharp one will leave a fine cut with minimal effort.
3. What oil do you use to sharpen chisels?
Light oil is best-suited. For example, mineral oils, are light and do not harden or go putrid. Light oils help in better sharpening and do not impede the oilstone’s functionality. Olive oil is also a viable substitute.
4. How do you prepare a new chisel?
Chisels come manufactured in standard sizes and sharpness. A new chisel’s bevel is at 25°. Sharpening it further using the angle grinder, you can create it at 30°, for better productivity and edge.
Sharpening a chisel with the angle grinder is the best and flexible solution, with minimal time. It ensures the edge holds, and the problem of excess heat can be easily overcome by dunking the chisel in water.
However, the last few steps to create the bevel and sandpaper finishing are essential to give the necessary touch to the entire edge. Frequent and timely sharpening would also ensure durability and long usage.
Adhering to the enumerated and detailed steps will allow you to sharpen a chisel perfectly.
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