How to use a hard felt bench grinding wheel on knives?

Getting a razor-sharp, polished edge on a knife can be frustrating and slow. A dull knife is dangerous, and using the wrong tool can easily ruin the blade. A hard felt wheel on your bench grinder can give you a professional, polished edge, fast.

To use a hard felt bench grinding wheel on knives, first ensure the wheel is secure and the guards are in place. Apply a polishing compound to the spinning wheel. Then, hold the knife blade at a consistent, shallow angle against the wheel’s rotation, moving it smoothly to polish the existing sharp edge.

But getting that perfect mirror finish isn’t just about turning on the grinder and hoping for the best. There is a right way and a wrong way to do it. Let’s break down the entire process, starting with a common question we get in our factory: can you even use a bench grinder¹ to start making a knife from scratch?

Can you use a bench grinder to make knives?

You want to try knifemaking, but you think you need expensive, specialized equipment. The high cost of belt grinders can stop your project before it starts. Believe it or not, a simple bench grinder can be a powerful tool for your knifemaking journey.

Yes, you can absolutely use a bench grinder for knifemaking, especially for profiling the blade shape and rough grinding the bevels. It’s a cost-effective way to remove a lot of material quickly before moving on to more precise tools for finishing and sharpening.

Going Deeper into Knifemaking with a Grinder

A standard bench grinder¹ is excellent for the initial, heavy-duty work of knifemaking. It helps you take a flat bar of steel and cut out the basic shape, or profile, of your knife. It can also be used to begin grinding the bevels, which are the angled surfaces that form the cutting edge. However, a bench grinder spins a rigid wheel, which makes it hard to create the flat, precise surfaces needed for a high-quality knife. Most professional makers use a belt grinder, which uses a flexible abrasive belt. This gives them much more control.

I remember my first attempt at shaping a blade on an old grinder in our factory. The key is to use very light pressure and keep the steel moving. If you press too hard, you can easily overheat the steel, which ruins its hardness.

Think of the bench grinder as your starting point, not the finishing tool.

How to use a bench grinder step by step?

You have a bench grinder, but you’re intimidated by its power and speed. Using it incorrectly can damage your workpiece or, worse, cause serious injury. This fear can keep a useful tool gathering dust. Following a few simple steps will help you use it safely every time.

To use a bench grinder, first inspect the wheel for damage and ensure guards are in place. Stand to the side, turn it on, and let it reach full speed. Gently bring your workpiece to the wheel, keeping a firm grip and moving it constantly to prevent overheating.

A Practical Guide to Using Your Grinder

In our Henan factory, safety is the first lesson for every new operator. We always say, "Respect the wheel." This means checking your setup every single time before you start. A grinder is a simple machine, but it demands your full attention. Here is how we train our team.

1. Preparation and Safety Check

Before you even plug it in, check everything. Make sure the grinding wheel has no cracks. Tap it gently; a good wheel makes a clear ringing sound, while a cracked one sounds dull. Ensure the safety guards and eye shields are secure. Adjust the tool rest so it is about 1/8 inch (3mm) from the wheel. This prevents your workpiece from getting jammed. Finally, always wear safety glasses.

2. The Grinding Process

Stand to the side of the wheel, not directly in front of it. Turn the grinder on and let it get to full speed. Hold your workpiece firmly with both hands and gently press it against the wheel. Use the tool rest to support the workpiece whenever possible. Keep the workpiece moving back and forth across the face of the wheel. This ensures an even grind and helps prevent the wheel from wearing down in one spot.

3. Cooling and Finishing

Metal gets hot very quickly. For high-carbon or high-speed steel, like in many tools and knives, heat will ruin the temper. This makes the steel soft. Keep a container of water nearby and dip the workpiece in it frequently to keep it cool. Don’t wait for it to change color. Once you’re done with the rough grinding, you can move to a finer grit wheel or other methods for a smoother finish.

What is a bench grinding wheel used for?

A bench grinder might seem like a one-trick pony, just for sharpening a few tools. You could be missing out on its full potential, leaving a versatile tool underused. Your bench grinder is actually a multi-purpose machine for shaping, cleaning, and polishing many materials.

A bench grinding wheel is primarily used for grinding, cutting, sharpening, shaping, and cleaning metal objects. Depending on the wheel installed—from coarse grinding wheels to wire wheels or felt polishing wheels—it can handle tasks from heavy material removal to fine surface finishing.

The Many Jobs of a Grinding Wheel

The wheel you attach to your grinder defines what it can do. At our company, Reliable, we produce a huge variety of abrasive wheels because each one has a specific job. Choosing the right wheel is everything. A bench grinder is not just one tool; it becomes many different tools depending on the wheel you use. It’s a core machine in almost any workshop that works with metal. Understanding the different wheels unlocks the true power of your bench grinder for countless tasks beyond just simple sharpening.

Can you use a grinding wheel to sharpen knives?

Your knives are dull, and hand-sharpening them takes forever. You’ve heard that using a powerful grinder can easily ruin a knife’s temper or grind away too much steel. With the right technique and wheel, a grinder can be the fastest way to put a sharp edge on a knife.

Yes, you can use a grinding wheel to sharpen knives, but it requires care. Use a fine-grit wheel and light pressure to avoid overheating the blade, which can ruin its heat treatment. Keep the knife moving and maintain a consistent angle for a uniform edge.

The Art of Grinder Sharpening

Sharpening a knife on a grinder is different from polishing it with a felt wheel. Sharpening removes metal to create a new edge. Polishing refines and cleans that edge for a mirror finish. I’ve seen many good knives ruined by impatience. A moment of pressing too hard creates a blue spot on the edge, and just like that, its ability to hold an edge is gone forever.

1. Choose a Fine-Grit Wheel

For sharpening, you don’t want to remove a lot of material quickly. A coarse wheel is too aggressive. Use a fine-grit wheel, usually made of white aluminum oxide, designed for sharpening.

2. Find the Correct Angle

Most kitchen knives have an edge angle of about 20-25 degrees. Hold the blade against the wheel at this angle. The key is consistency. Try to lock your wrists and use your arms to move the knife.

3. The Grinding Motion

Hold the knife securely and move it smoothly across the wheel from the heel to the tip. This creates a uniform bevel. Always grind against the rotation of the wheel (with the edge facing up). Grinding with the edge pointing down can cause the wheel to catch the blade and throw it from your hands.

4. The single most important thing: Don’t let it get hot

As I mentioned, heat is the enemy of a hard knife edge. Use very light pressure. Dip the blade in water every few seconds. If you see the metal turn straw-yellow or blue, you have already overheated it, and the temper is lost in that spot. Go slow. A little practice on an old, cheap knife will give you the feel for the right pressure and speed.

Conclusion

A bench grinder is a powerful tool for knife sharpening, making, and polishing. With the right wheel and a strong focus on safety and technique, you can achieve professional results efficiently.