I have mentioned in previous posts that my preferred method of sharpening for chisels and plane irons is on my Eze-Lap diamond plates using a honing guide. I have also acknowledged that I ought really to try and ditch the guide and learn to do it freehand. Well, recently, I have experimented with some freehand sharpening with plane irons, with surprisingly good results. However, I have found that instead of a nice flat bevel, I end up with a rounded one; a convex camber if you will, that curves back from the cutting edge. I have learned from my maestro, Paul Sellers, that far from being a problem, this camber actually strengthens the cutting edge, supporting it and lengthening the time between sharpenings. I don’t know if this is true or not, but it certainly doesn’t seem to have a negative effect.
Anyway, the reason I am writing this post is because I doubt that a freehand approach will be suitable for my mortise chisels, and I don’t think that they will fit into my honing guide. So my question to you is: How do you sharpen your mortise chisels? Also, what angle do you sharpen them at? I have measured the bevel on mine and it is 25º, which is apparently fairly standard, but I have read that a secondary bevel of 35º is advisable. I am at a loss at how to achieve this with the equipment presently available to me.
If anyone out there can shed any light on this I would be most grateful. I have searched online for an answer, to no avail. Perhaps my googling skills aren’t up to it, so if anyone could point me towards some kind of tutorial, that would be fantastic. Any advice would be welcome.
Thanks everyone. Hopefully I’ll see you in the comments.
gb
goatboys woodshop 
I have a little to add but i will really be interested in the replies. I recently started collecting old flat sided firmer chisels and had some time recently to sharpen then only to find that my Eclipse style guide won’t hold them securely. I’ve considered picking up another and modifying the angled sides to flat. Maybe that would work for you if all your chisel sides share a common angle?
Bill
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Set them on that 25 bevel. Lift the handle a bit and sharpen until you have wire edge. Remove that wire edge and chop a mortise. Next time do the same or remove the secondairy first on a coarse stone. There is no need for any precision regarding the angle. 35 is just a number. A mortice chisel doesn’t need to be sharpened to the same level as for example a pairing chisel.
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I use a bevel gauge set to 32 degrees or so and try to match it. Over 30 and under 40 and you’re good. The real key is make sure you don’t move your arms laterally to avoid skewing the blade. That’s the key part, the rest is just sharpening a blade. And NO back bevel.
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I freehand my mortise chisels, though the result isn’t fantastic. You’d think a mortise chisel would be easier, with such a lunking big hunk of steel to register against the plate, but the opposite seems to be true. Here’s hoping somebody can chime in and enlighten us on their methods to try.
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Lie-Nielsen has just started shipping an “improved” Eclipse style jig with a mortice attachment coming later. I’ve received the base jig with the mortice attachment on B.O.. I expect it will work for what you want. I agree with Kees, mortice chisels do not need the same level of sharpness as a bench chisel but it helps if they are square. The jig should keep ’em square.
BTW, congrats on sharpening freehand, it makes life better and the blue birds of happiness sing.
ken
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I have the Narex mortise chisels too. I have found a primary bevel of at least 27 and a secondary of 30 to 32 gives me good penetration and ok durability on the edge. I saw edge failure in sapele with a lower angle.
I use the veritas jig, which can just handle the thickness, down to 3/8 wide. Below that the veritas jig loses grip on the narrow chisel. I have seen the new veritas narrow blade jig but haven’t tried it.
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I do all my sharpening freehand. But for mortician chisels I will grind if the last grind had been honed away. I have a huge old grindstone, about 24 inches in diameter, so it makes a rather shallow bezel, or curve. On the stone (I start with diamond) I feel for the chisel to be supported by the fore and aft ends of that bezel. I can use my fingers hanging down over the sides to just barely touch the stone. That sets the angle and gives me a pretty good guide for keeping that angle. Morticers are the only edge that this matters on.
Don’t microbevel, it just acts as a curve, instead, sharpen to a low 30s angle. This gives the strength you need and works well to hog out even tough woods like oak or hickory. If I only worked pine, I would go for 25 degrees. On older chisels the steel can be of varying hardness, so a little experimentation might be in order as to what angle is best.
With that bezel, you might get 10 honing before you need to regrind.
Don’t throw the guides away yet! They can really help if you get off or need to rehab someone else’s bad angles.
Good luck
jason
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The bevels and secondaries previously mentioned are about normal.
I don’t worry about optional opinions. Most of the second hand tools I acquired needed new blades due to freehander’s who thought they knew how to sharpen. Secondhand chisels were temper ruined on wheels, so I committed to new. My cheap guides do the widest normal plane irons and most chisels. I use both faces of the wheeled guides. I don’t challenge my lack of machine-like skills, like I don’t drive without a seat belt. You don’t ruin an edge with a guide, unless you try.
I have sharpened Japanese chisels “free hand” but they are done flat to the stone–no secondary bevel. My fingers looked like hamburger afterwards. I am reconsidering the second bevel.
But free hand, by all means. They are your tools and your option to treat as you wish.
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I might suggest you try chopping mortises with your standard bevel edge chisels. I learned this method from Paul Sellers several years ago when I took a month long class with him in New York. The same free hand sharpening with the convex bevel works great.
If you do want to use mortise chisels, the same convex bevel will work just fine.
My only word of caution for free handing narrow chisels is they can be taken out if square very easily.
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Thanks fellows. All good info. I’ve got some thinking to do. I will probably try my honing guide again, as a comment on another post suggests that it should work. Failing that, I’ll bite the bullet and go freehand. At least I know not to get too preoccupied with the angle of the bevels. Thanks again, everyone. Much appreciated.
gb
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I use a veritas mark 2 on my Narex mortise chisels. I find it works fine for them down to about 3/8″. For the narrower ones I go freehand – I figure the amount I am out of square will be pretty small. I haven’ convinced myself to pay for the new veritas narrow-chisel holder. The clamp on the veritas is just deep enough to take the thick chisels. FWIW I have found that a sharpening angle of 30% works well (sapele, cherry, pine, whatever). At a narrower angle I see edge failure on my Narex.
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Hi there,
unfortunately I’ve got just one mortise chisel and I don’t need to sharpen it, because it is not really used. Anyway. But I made the same experience as you as I switched from the honing guide to free hand. I guess that the resulting cutting edge is pretty good because we are tending to tilt the chisel while sharpening and that will establish somehow a micro bevel every time.
In one of the Paul Sellers videos he mentioned that he doesn’t care about rounding the bevel, because he is regrinding the chisels from time to time.
So I followed his advice. I’m sharpening free hand during a project to get back quickly to work. And if I’ve got time and will do some workshop cleanup I grind my chisels in a honing guide, starting on a coarse diamond stone.
Cheers,
Stefan
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