Sharpening a Chisel




Introduction: Sharpening a Chisel

About: self-unemployed maker

I have unreasonable sentimentality about Stanley Model 40 chisels. I started buying them about 30 years ago just as they were being discontinued. They seem to sharpen easily and hold a good edge. I was always missing the one inch chisel and recently was lucky enough to find one on eBay.

Step 1: Beat Up Chisel Handle

When I received it, I noticed that the back of the handle had been hit pretty hard over the years.

Step 2: Badly Sharpened Bevel

When you saw the bevel, it was no surprise that someone had hit it that hard. It looks like it had been sharpened multiple times but each sharpening had only added another facet to the bevel.

All chisels, whether new from the factory or used, need tuning before they work well.

Step 3: Reason #1 for Sharpening

The primary reason to sharpen a chisel is shown in this photograph. You can see how poorly the chisel cut a piece of softwood and all I was trying to do was pare a small piece off the corner. The chisel crushes the fibers until they break rather than cutting them.

Step 4: Reason #2 for Sharpening

And there’s a second less obvious reason. For 35 years, I have carried a reminder on my left palm of the dangers of working with a dull chisel.

Step 5: The Back of the Chisel

Ideally, you want to have two perfectly smooth surfaces, the bevel and the back, meet to form the cutting edge. Any imperfections in either will reduce the sharpness of the chisel.

Here’s the chisel back when I received it. You can still see the machine grinding marks left from the factory.

Step 6: Flattening the Back

The most overlooked part of tuning a chisel is flattening and polishing the back.  The easiest way I’ve found to do this uses sandpaper and a piece of plate glass. Using a spray bottle, I spray water on the back of a sheet off sandpaper which usually creates enough suction to have it adhere to the glass. Depending on the condition of the chisel, I’ll choose the appropriate grit but generally I start with 80 grit open coat silicon carbide sandpaper. I move the chisel back and forth (along the long axis of the chisel), keeping the back, flat against the paper, until the marks on the back are consistent across the surface.

Step 7: Refining the Back

I usually use 80, 120, 150 and 220 sandpaper. After all, I only have to do this the first time I sharpen a chisel. Use each grit moving the chisel until you get a consistent pattern

Step 8: Polishing the Back

After using sandpaper, I polish the back with a set of Japanese water stones.

I end with an 8000 grit waterstone or when I run out of time or patience

Step 9: Hollow Grinding the Bevel

After flattening and polishing the back, I grind the bevel. My favorite tool for doing it is a water cooled large diameter grindstone. It turns slowly and leaves a beautiful finish. You can also do it on a regular grinder but you have to be very careful not to overheat the tool and lose the temper of the steel.

I apply pressure very close to the edge of the tool and use a jig to ensure that the edge of the blade stays square

Step 10: Honing the Bevel

I use a 4000 grit water stone to hone the bevel.  I apply pressure close to the edge and use my other fingers to support the weight of the chisel. I start by setting the back of the bevel on the stone and slowly rocking it forward until the tip of the chisel touches the stone. One of the primary advantages of the hollow grind is that the chisel almost locks into place because there are only two points of contact

I gently pull back on the chisel four or five times and look for the small bevel forming at the two points of contact. Once I’m happy with the bevel, I finish up with an 8000 grit stone to polish the bevel.

I’ve tried various jigs over the years to hone the bevel but I find most of them way too fussy for me. If you have trouble doing it by hand, there are some good jigs commercially available.

Step 11: Testing for Sharpness

There are many ways to test for sharpness. You can gently use the chisel on your fingernail, try to cut a piece of paper or if you have the means, try shaving the hair on your arms.

After a while, it’s easy to know whether the chisel is really sharp by just (carefully) running your finger across the edge

Step 12: The Real Test

The real test is whether it cuts wood cleanly. Test it on the edge of a block of wood. A piece of softwood requires a sharper chisel than hardwood to cut cleanly

Step 13: Oil the Chisel

Finally, dry the chisel and put a light coat of camellia oil (tea seed oil) on the chisel. It’s an edible non-toxic oil that helps prevent rusting.

When the chisel gets dull, you can just hone and polish the bevel. After five or six times, you’ll have to touch it up on a grinding wheel before honing



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    33 Discussions

    Im having a hell of a time getting a shave worthy edge on my chisel. I have honing stones some feel like a glass surface while others feel like the can scrape diamonds to dust. All my stones were left to me from my grandfather. They are mostly well used.

    Fantastic instructable! Thank You!

    Last comment I promise.
    Given the fineness of the mediums you are using I was interested in just how much difference the final polishing of the bevel made so I refinished the bevel on the chisel with stannic oxided slurry on an oiled paper lap. It turns out to be quite significant.[see image] This produces a very slight bull nosing of the bevel. Probably better to use the slurry on a steel lap.

    Kind Regards,


    blade polished IMG_0170.jpg

    Thanks for the test Carlbass. Leaving a satin like sheen on soft wood end grain does indeed appear to be a more more rigorous test than shaving or paring nails.

    I was quite pleased with myself that the old chisel [Swedish c. 1910] I was restoring seemed to meet the end grain test till I took a look at my handy work under a microscope.
    What appears to the unaided eye as a mirror finish can be deceptive! I still have much to learn. What look like chips out of the edge are in fact tiny corrosion pits on the flat of the blade.


    blade pair IMG_0163.jpg

    Thank you, that was most instructive. I should have consulted it long ago. I have a rather fundamental and possibly naive question. I sharpen my chisels on the diamond laps I use for stone cutting. I get a mirror finish and they seem to work OK but are they really "sharp"? The test I use is whether I can dry shave [hair] with them. There must be a much more professional test known to the experts?

    Kind regards,

    David Hogg.

    1 reply

    I do the same and shave the hair on my arm. I've seen others shave a fingernail and the best test is to pare a piece of softwood end grain.

    i recently got a chisel but i need to sharpen it. Do you have any instructables for how to use an oilstone to sharpen it? I can't get a grindstone. i tried to use a cylinderical dremel bit but it just made it look very polished and still blunt.
    Any help Please?

    Beautiful job on the chisels and the instructable.Another alternate sharpening is for working with melamine and laminates and the pvc edgebanding that is used with them. We have a huge edgebander at work that glues ,end cuts, routes and scrapes top and bottom and then buffs all in one pass....but if you dial it in to perfection any inperfection in your material gets highlighted by having it's finish removed. The solution is to set it close and then final trim and scrape with a hand chisel. This chisel should be shapened normal and then turned over and have a second bevel put on the other side for about 1/16 inch and 5 degrees.Then round the corners slighty so it don't dig in. It is kept sharp but the second bevel seems to make it glide over the laminate while trimming the edge.

    I keep a 8000 slip for the bevel - those water wheels are expensive and take up space I'd rather use for something else.

    lovely tutorial, the moment i saw the honing of the edge i thought of a straight razor, and i never imagined this things needed to be so sharp

    Nice instructable. I use a Veritas sharpening jig, which makes it easy to put a proper bevel on if you don't do this sort of thing every day. I also use the sandpaper-on-glass trick for sharpening as well as prepping the back, going to 1600 grit. Cheaper than waterstones ;-)

    Your instructable is great. It has been a very long time since I was taught how properly sharpen a chisel. I agree with all the steps you have shown, with one possible variation. I follow up hand stoning with a leather strop. I have an old shoe sole that puts a very high polish on the blade and assures a razor edge, needed for work on soft wood. Incidentely, the same process should be used on hand plane blades. Thanks.

    1 reply

    I agree completely. I mistakenly left it out of the instructable but I often strop the tools on a piece of leather glued to a board that I rub that has rouge on it

    OOoohhhhh ... didn't know i had to sharpen my chisel.
    In a way it make sense.
    Thanks for this instructable that'll be really handy :)

    A thorough write up!
    It's funny how sometimes we get used to working with dull tools and don't realize what a difference a sharp blade makes.

    5 replies

    Sometimes dull blade is better. Believe it or not a dull knife cuts foam roofing insulation much better than a sharp one does. Drove me nuts to learn it, but I've come to accept the fact today. I wouldn't want to butter my toast with a sharp blade either. But we'd use butter knives on roofing insole.

    For everything else I got used to sharp blades at a very young age. 20 years ago I thought I knew everything there was to know about sharpening too. Since then I've learned a thing or two though.

    Today for instance I wouldn't consider a chisel edge fully sharpened unless it was stropped. Wire edges are for scrapers.

    Just something about it. For years I didn't do it and wondered why my edges dulled more quickly than I thought they should. Today I think it was because the wire edge was bending over on the blade. A strop until the wire edge breaks off cures that.

    Yeah instead of saw sharp they get slippery sharp after stropping. Like you polish out the last scratches on the edge. Do you charge your leather strop with rouge? I have a stick of this red stuff I use. I can't even remember where I got it from. I just know I got it now.