How to Sharpen Jointer Blades

A jointer is a woodworking machine used for smoothing surfaces and cutting corners. The blade is a vital part of the jointer and needs to be regularly sharpened for maximum efficiency. If you don’t know how to do it, I am going to show you how to sharpen jointer blades.

How to Sharpen Jointer Blades

With regular use, the blades of your jointer will eventually wear out and become blunt. You may decide to replace or sharpen them. When sharpening, you may remove the blades. Alternatively, you can sharpen them directly on the cutting head.

The first step to learning how to sharpen the blades is understanding their arrangement on the jointer. This way, you will know how to easily access them for sharpening if you don’t want to go through the hassle of removing them. 

Understanding Jointer Blades Arrangement 

Jointers have cutter heads that contain two or more blades thoroughly sharpened. You may arrange the blades on square, cylindrical, helical, or spiral cutting heads. The blade arrangement is such that the cutting edges extend from the cutter head. 

The cutter head’s rotational axis is parallel to the table surface and perpendicular to the feed direction. As the head spins in a direction opposite the infeed, the blades cut when they contact the surface. 

Now that you know the blade arrangement, let’s go over the easiest ways to sharpen them. 

Methods to Sharpen Jointer Blades 

I recommend you sharpen the blades around three or four times, after which you’ll have to replace them. 

Before sharpening the blades, you need to ensure the blades and surfaces of the jointer are clean. Once they’re clean, there are two commons ways to sharpen jointer blades: 

• Using the jig method 
• Sharpening without removing 

Method One: Using the Jig Method 

This method of sharpening requires that you remove the blades. 

What you’ll need: 

• Piece of planed wood for making the jig 
• Allen keys for loosening and tightening bolts 
• P120, P320, P800 grit sandpaper or sharpening stones for sharpening 
• Degreaser for cleaning out the sawdust 
• Wedge to hold the cutting edge in place 
• Water and a set of scrubbing brushes for cleaning the blades

Procedure 

The following is a detailed step by step procedure on how to sharpen your jointer blades safely.  

Step 1: Turn Off the Jointer 

If you don’t turn off the jointer, the machine may accidentally start and injure you.  Retract the guard and put a wedge under it. This will hold it back and keep it steady. After that, remove the fence to allow for more space for movement. 

Step 2: Loosen the Blades 

Carefully loosen all the bolts holding the blades to the cutter head. Each blade has four bolts holding it in place. Remove all the blades and the holders. Make sure to label them to ensure every blade goes back to its original position. 

Step 3: Clean the Blades

Use an industrial strength degreaser to clean up the cutter head and make sure to remove all the sawdust that may have gathered over time. Clean the blades with water and make sure to dry them 

Step 4: Set the Blades

If you do not have a premade jointer blade sharpener jig, you can make one. To make the jig, you will need to find the blade’s exact angles and saw the two strips of the slopes on a well-planned piece of wood. The usual angle is 450°.

After marking the angles, use a tilting vise and column drill to make holes for fastening screws. Make sure the screws are in apposition to hold the knives parallel to each other.

Step 5: Sharpen the Blades

Mark the edges of the knives to make sure you are sharpening the correct plane. Ensure the blade’s chisel shape while rubbing it on sandpaper is firmly glued to a flat surface. The surface may be wood, granite, or thick glass. You may also use sharpening stones. 

Step 6: Ensure the Edge of the Blade is Straight 

Hold the blade against an instrument like a try square and try shining light from the back to check. Repeat for all the blades. If any blade is not straight, you may have to sharpen it again. 

Step 7: Test the Blades

Put the blades back to their holders and tighten the gibs. Use High-Pressure Laminate parts to adjust the height of the blades. The springs in their positions will push the blades upwards. When the blades are at the same height as the work table, tighten the blades’ nuts. 

Remove the clamping and try turning the drum. The drum should turn; if not, then make readjustments. While clumping the blades, you may repair the nicks as well.

Method Two: Sharpening Blades While In Position 

If you don’t like the hassle of removing the blades, sharpening them, and then reinstalling them, you may use this other method to do it.

Step 1: Disconnect the Jointer 

Make sure to disconnect the jointer from the power supply. Remove the blade guard and remove the fence. 

Step 2: Set the Blades

Raise the infeed table to maximum height and position the cutter head. Do this to ensure that the blade you want to sharpen is the apex of travel and fits the locking jig. Lower the infeed table until the jig holds tightly. 

Step 3: Sharp the Blades

Make sure to protect the outfeed table from honing with tape. Pace a piece of wood across the table and lower the outfeed table until the block of wood touches the knife. 

Use a sharpening stone for sharpening. Begin with the P600 grit and repeat the strokes, then move on to the P1200 grit. Draw the stone back toward the outfeed table. Check to make sure the blade edges are straight.

Repeat for the other blades. 

Step 4: Test the Blades

Test the blades to see if you have the required sharpness. If not, repeat the process.

Tip: You need a lot of patience while sharpening jointer blades. Sometimes you might need to redo the process severally to get the required sharpness. 

Safety Precautions While Sharpening Jointer Blades 

According to the Woodworkers Guild of America, jointers, as well as planers and other machinery are responsible for 10,930 annual injuries in the workplace. Here is how to keep yourself safe while sharpening jointer blades: 

• Wear protective clothing like gloves 
• Ensure there is no power supply to the jointer 
• Ensure that you clamp the movable parts correctly 
• Avoid touching the blades 
• Wear protective eyewear 

Conclusion 

Your jointer is only as useful as its blades and its cutter head. However, sharpening these blades can sometimes be challenging. It requires some skills and needs you to be patient and confident. I believe that the tips above will help you sharpen jointer blades correctly.