How to Sharpen Jointer Knives

What You'll Need
Sharpening stone
Water or oil
Piece of scrap paper

With the benefit of wood planers being dependent on the jointer knives within them, it is important to keep them sharpened. In order to undertake this process effectively, it will be necessary to follow all the required steps correctly.

Step 1 – Examination

Depending on the type of jointer knives that you are working with, you may not have a significant amount of access to the blade. This is necessary to enable you to sharpen it so you will need to consider the tool carefully. If necessary, measure the free edge of the blade to determine whether you will be able to sharpen the blade without removing it. This step will also enable you to determine the location of all the fasteners holding the tool together.                                

Step 2 – Disassemble

Most tools that make use of jointer knives will be able to be taken apart for the purposes of maintenance and repair. Screws will most often be used for this purpose but bolts can also be used so you must ensure that you have the correct tool to remove them. Withdraw the necessary fasteners to enable you to free the jointer knives. You will be able to examine the blade properly and you are likely to find that it comprises a flat edge and a beveled edge.

Step 3 – Prepare

Use a cloth to carefully wipe the jointer blades to ensure it is free of any debris. Place the sharpening stone on firm flat surface and dampen the upper surface with water or oil. Check the instructions that came with the sharpening stone to determine which substance is best to use.

Step 4 – Sharpen

Begin by laying the flat edge of jointer knives against the sharpening stone and place your fingers on the top side of the blade. At this point you will be able to rub the blade against the stone using a figure of eight or back and forth motion. Test both methods to determine which one is easier for you to undertake. You should not need to undertake this process on the flattened edge more than ten laps. Once the flattened edge has been complete, turn the blade over to work on the beveled edge which is the main cutting edge. Position the blade so that the slanted edge is in contact with the sharpening stone, making sure that your fingers are clear. Avoid the risk of getting your fingers trapped between the blade and the stone by pressing them to the upper surface. Depending on which is most comfortable, use a circular, figure of eight or back and forth movement to hone the edge of the blade. Make sure the that you maintain contact between the stone and the blade and wet it again if and when it becomes necessary. Depending on how dull the blade has become, work in rounds of ten and check your progress by using the blade to cut a piece of paper and check whether it becomes easier.