Chopping mortises – bevel-edged or mortise chisels (video)
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Chopping the mortise–Bevel edged or traditional mortise chisel
I recently saw a Youtube video put together by Lie Nielsen where it shows a mortise being cut behind glass; the idea was to show the progression of the traditional method using a traditional ‘pig-sticker’ mortise chisel and I understand it was Roy Underhill who came up with the idea, which was wonderful.
As a boy in school I was shown this method and indeed we were trained that way, but once I left school and started to chop mortises in the everyday of life I found that lightweight chisels chopped more effectively, especially on the lighter work of furniture making and joinery rather than the heavy bank doors once common that had 3/4″ wide 5″ x 5″ deep twin and double mortises in mahogany and oak (that’s two or four mortises per corner sometimes on the bottom and middle rails). In my apprenticeship, most of the men chopped mortises with a Marples bevel-edged chisel. They used the ones shortened by wear, admittedly, but I used my then brand new Marples bluechips and have done so now for almost five decades. In all of those years using these and other makers, I have never bent a chisel once. Furthermore, I have trained 3,500 woodworkers, many raw beginners to the bench, and I have never found one chisel bent either.
Growing in my craft, I found myself changing the pattern and developed the one I teach and advocate today. No matter the chisel, this method is fast and highly efficient and so effective I find myself able to consistently chop a 4″ long mortise 1 1/2″ deep and 3/8 wide in around 4 minutes. I own a mortise machine, but seldom use it because of this. Anything and everything you have seen me work on in the past three years has been cut by hand methods.
My reason for staying with the bevel-edged chisels is indeed as much the size of the bevel cutting edge itself as the thinness of the steel chisel used. Obviously, because it’s so small (narrow), the steel penetrates very effectively in any wood. The lighter weight of the chisel means I can easily drive it with minimum counter-opposition from the weight I inevitably get with the heavy framing chisels.
Sparked by the idea of the Youtube video, we decided to show the method I used and at the same time try to show the contrast between the traditional mortise chisel and the bevel-edged chisel. The reason being that traditional mortise chisels are not so readily available and accessible to everyday woodworkers and to show how effectively this method works with either chisel.
Working on massive doors in the pre-machine age and making such projects day in day out I would indeed use a heavy weight traditional mortise chisel. I worked on two large doors for the National Trust’s Penrhyn Castle two years ago and so I do not challenge the ancient craftsmen who used and developed them for such work. Neither do I challenge them for fine work either. An English five-bar field gate had ten mortises 3/4″ by 4-5″ through stile 4-6″ wide and a man made one in a ten-hour day complete with bracing in solid oak. That man used the kind of mortise chisel I am talking about. These chisels were wonderfully made to last the lifetimes of two craftsmen. At the everyday bench for we woodworkers, we use good chisels carefully and work with what we have at hand.
A fascinating video on the basic subject of chopping a
mortice – thank you.
But isn’t it all a case of chisel geometry?
I must confess to using a bevel edged chisel (Stanley, with
black plastic handles – still got ‘em) for years because that and an old
workmate was all I had. I’m glad to say that I’m a bit better equipped in the
bench department nowadays.
Years later, and some years ago, I recollect seeing a video (VHS,
no less) by the late Jim Kingshott who advocated honing the backs and both
sides of a mortice chisel, to provide an edge capable of dealing with stray
fibres on the sides of the mortice as the bevel descended forcing the sides in
a backwards arc. This implied that it was parallel along its length, but
tapered slightly across the blade.
I did notice that as the mortice chisel took longer to chop,
it tended to become less free and bind as it got deeper in comparison with the
bevel edge chisel, which prompts me to think that side friction has a part to
Again I recall buying a second hand mighty pig -ticker of a
chisel, about ¾”, for some big and deep door stiles in Oak. When honing it I noticed
that it tapered very slightly from tip to handle…….
Personally, I believe that deeper, longer mortices, especially
in harder woods, like Oak, demand less friction from the chisel as it descends.
Unless you are gluing to a high specification, a bit of chain-saw oil comes in
But all good stuff, I do like to see ideas and set-in-stone
practices challenged from time to time.
This is another great demo! Thanks for taking the time do this.
I have a question though. You say, take care to not bend the bevel-edged chisel. What exactly do you mean? Is it when you lever the chisel to break the chips? Other than hitting the chisel with mallet and have it bend on its own, is there another way for them to bend?
Sorry Paul, this comparison seemed a bit sophistic to me. There’s no doubt your method works, but: nn OBMC doesn’t need to be used with a little toffee hammer, and the strange attitude of the chisel in relation to the work does nothing to help speed, accuracy or work holding. Further, using the chisel backwards means the shaft edges won’t provide a clean cut on the sides – something you highlighted as a shortcoming of the mortise from the proper chisel. Try a dem comparing your bevel edged method against an OBMC used properly.
Why don’t you show us a proper comparison Steve? We would all be interested. Seriously, please let us know if/when you do one.
This is a great demo. Regardless of the type of chisel used, it shows how effective this method is, just as Frank Klausz’ original demo-behind-glass did.
Well said. Funny thing is, I ave a set of Faithful chisels i bought in to test and they have proven to be excellent chisels. I must say, though, that I like Sorby chisels very much. More expensive, yes, but for a longlife user I think they fit the bill.
I’m just starting out doing woodworking by hand. I’m going to be doing interior door in my house. The mortises are going to be 3″ deep. Would you still use the bevel chisel for these?
Great video, and eye opening. But I do have a simple question.
I am preparing to build a new workbench using mortise and tenon joints. The mortises will be 1/2” by 5”. Can I cut these with a 1/2” chisel? My gut tells me to go with 1/4” or 3-8” to stay away from the sides and risk widening the mortise. Your thoughts?
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