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Sharpening Woodworking Chisels
By Sam Conder
While attending a "fundamentals of woodworking" class taught by Marc Adams at the Indianapolis woodworking show a few years ago, I was most impressed with his simple yet effective method of sharpening woodworking chisels. I contacted Marc and asked him for permission to write an article for BT3Central on how to sharpen chisels using his method. As expected, Marc was very receptive to the idea of sharing one of his "secrets". His exact response to me was " Absolutely, please feel free to teach anything you learned from me." So let's dive right into this and sharpen some chisels.
Most chisels will come coated in a packing varnish to keep them from rusting. You must first remove this varnish with a rag and lacquer thinner. Next, it is an imperative first step to flatten the back of the chisel. Even though the back may look flat, it is not. The good part is that this flattening process only has to be done once in the lifetime of the chisel.
The back is flattened using a dead flat surface and pressure sensitive adhesive (PSA) sanding disks. Some people use a piece of glass or marble, but I like to use the bed of my jointer. Stick a 120 grit PSA disk to the flat surface. Next, work the back of the chisel back and forth across the sanding disk, applying moderate pressure. After 20 or so strokes, take a look at the back of the chisel. I bet you will see a low spot where the chisel was not perfectly flat. Continue until the back looks flat and there are no low spots.
Next, using the same method, progress through 220 grit, 320 grit, 400 grit, then 600 grit PSA disks. These PSA disks are available from a variety of sources including Klingspor. When you are finished with the 600 grit the back of the chisel should have a mirror finish. The purpose of this flattening process is to remove the deep scratches that go through the cutting edge of the chisel. Otherwise, the edge would look like a serrated knife if viewed under a microscope.
With the back side flat and polished, the next step is to create a fine burr off the bevel side of the chisel. To do this I use my belt sander. I install a "dull" 150 grit belt into my handheld belt sander and clamp it into my Workmate with the belt up. With the sander turned off, find the angle of the bevel by holding the chisel against the belt and rocking it back and forth until you feel it flat on the sander. Hold the chisel at this angle with the chisel skewed a bit so that the belt runs at an angle to the edge of the chisel. Keep your index and middle fingers down near the edge of the chisel but keep them clear of the belt. With your other hand, turn on the belt sander for only a second or two. It doesn't take long to create the burr. Feel for the burr along the edge of the chisel by brushing your finger down the back of the chisel. DO NOT RUN YOUR FINGER PARALEL TO THE EDGE OR YOU WILL SLICE YOUR FINGER! Repeat this process using one or two second bursts until you can feel the burr. Once the burr is established, we are ready to move on.
The final step in the process is to remove the burr leaving a razor sharp edge. I use a muslin buffing wheel chucked into my drill press. Load the buffing wheel with Emery (black) buffing compound which you should be able to find right next to the buffing wheels in hardware stores and home centers. It will only take a second or two with the bevel side of the chisel in contact with the buffing wheel to remove the burr. Never place the back side of the chisel against the buffing wheel, it might round over the edges. Once the burr falls off the chisel will be the sharpest tool in your shop so treat it as such.
For me, this is the simplest, most effective and most inexpensive method for sharpening woodworking chisels. The PSA disks, muslin wheel, and buffing compound are the only expenses and they can serve "double duty" in your shop. My thanks go to Marc Adams for teaching me this method and for allowing me to share it.
By Sam Conder
While attending a "fundamentals of woodworking" class taught by Marc Adams at the Indianapolis woodworking show a few years ago, I was most impressed with his simple yet effective method of sharpening woodworking chisels. I contacted Marc and asked him for permission to write an article for BT3Central on how to sharpen chisels using his method. As expected, Marc was very receptive to the idea of sharing one of his "secrets". His exact response to me was " Absolutely, please feel free to teach anything you learned from me." So let's dive right into this and sharpen some chisels.
Most chisels will come coated in a packing varnish to keep them from rusting. You must first remove this varnish with a rag and lacquer thinner. Next, it is an imperative first step to flatten the back of the chisel. Even though the back may look flat, it is not. The good part is that this flattening process only has to be done once in the lifetime of the chisel.
The back is flattened using a dead flat surface and pressure sensitive adhesive (PSA) sanding disks. Some people use a piece of glass or marble, but I like to use the bed of my jointer. Stick a 120 grit PSA disk to the flat surface. Next, work the back of the chisel back and forth across the sanding disk, applying moderate pressure. After 20 or so strokes, take a look at the back of the chisel. I bet you will see a low spot where the chisel was not perfectly flat. Continue until the back looks flat and there are no low spots.
Next, using the same method, progress through 220 grit, 320 grit, 400 grit, then 600 grit PSA disks. These PSA disks are available from a variety of sources including Klingspor. When you are finished with the 600 grit the back of the chisel should have a mirror finish. The purpose of this flattening process is to remove the deep scratches that go through the cutting edge of the chisel. Otherwise, the edge would look like a serrated knife if viewed under a microscope.
With the back side flat and polished, the next step is to create a fine burr off the bevel side of the chisel. To do this I use my belt sander. I install a "dull" 150 grit belt into my handheld belt sander and clamp it into my Workmate with the belt up. With the sander turned off, find the angle of the bevel by holding the chisel against the belt and rocking it back and forth until you feel it flat on the sander. Hold the chisel at this angle with the chisel skewed a bit so that the belt runs at an angle to the edge of the chisel. Keep your index and middle fingers down near the edge of the chisel but keep them clear of the belt. With your other hand, turn on the belt sander for only a second or two. It doesn't take long to create the burr. Feel for the burr along the edge of the chisel by brushing your finger down the back of the chisel. DO NOT RUN YOUR FINGER PARALEL TO THE EDGE OR YOU WILL SLICE YOUR FINGER! Repeat this process using one or two second bursts until you can feel the burr. Once the burr is established, we are ready to move on.
The final step in the process is to remove the burr leaving a razor sharp edge. I use a muslin buffing wheel chucked into my drill press. Load the buffing wheel with Emery (black) buffing compound which you should be able to find right next to the buffing wheels in hardware stores and home centers. It will only take a second or two with the bevel side of the chisel in contact with the buffing wheel to remove the burr. Never place the back side of the chisel against the buffing wheel, it might round over the edges. Once the burr falls off the chisel will be the sharpest tool in your shop so treat it as such.
For me, this is the simplest, most effective and most inexpensive method for sharpening woodworking chisels. The PSA disks, muslin wheel, and buffing compound are the only expenses and they can serve "double duty" in your shop. My thanks go to Marc Adams for teaching me this method and for allowing me to share it.