Tenoned Mitre

Posted 19 October 2018

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A tenoned mitre is a strong corner joint alternative to a mitre that excels for picture or mirror frames and the like. Paul’s technique for cutting a tenoned mitre uses the router to guarantee accuracy and gives nice crisp joint lines.

52 Comments

    4. Sorry about the confusion everyone. We did indeed make a previous version but decided to re-do it without remembering we had already released the previous version. We think the updated version is better and are glad you found the joint correction useful.

      Sorry about the spam as well. There has been an increase of people trying to spam the site. We are working daily to try and eliminate it, so you should see it decrease and disappear… I hope.

      All the best,
      Phil and the Woodworking Masterclasses Team

  5. Hmm, fitting a single corner is one thing, but if one were making a four-sided frame, then any adjustments in final fitting of any of the corners might result in a frame that is out of square. How can that be resolved?

    1. If you’re fitting because you left to much on, like Paul left to much on the inside of the mortise, you wouldn’t run into problems because you end up where you wanted to be.

      If you have to fit further you’d have to make the exact same adjustment on the opposing piece (take the two pieces together and copy the knife knik of the fitted joint onto the other piece, then adjust the other piece to match). Of course that only works if you have some leeway in the end size of the frame because it’ll end up square but slightly smaller (if you only have to have an exact outside size you could oversize it slightly from the beginning and plane it down to it’s final size).

      Otherwise, apart from doing some very clever filling of gaps maybe you’ll probably end up having to redo it completely. Mitres are pretty unforgiving, and adding the complexity of a tenon only makes it more so…

      Having a very good square with a long area to position 45 degree angles on, like the one Paul is using, really helps as well. I never got the angle of mitres right until I bought the same one.

    3. I think the “error” came from not taking enough off, so that would mean that taking those shoulders down to where they’re supposed to be wouldn’t negatively affect this joint’s fit with the other 3 corners.

    4. I’d like to see a four corner fit up also. This is a lovely joint. I’m musing about where one would give up a bit of fit and the only place I can think of is the back shoulder. Loved the finessing… one wonders how Paul managed to cut a crown on that shoulder 🙂 but nevertheless the corrective actions and patience are good tips.

  6. Really liked the gauge jig that helps ensure the size of the mortise. The router then ensures the size of the tenon. Takes some of the mystery out of the complexity of this joint. I also enjoyed the final fitting and how Paul stepped through how he determined what he had to fix to get the tight fit all around. Well done all around. Thanks.

  7. Dear WWMC team:

    Thank you for this video/lesson.
    Although the similarities, in my opinion this new version is quite more helpful because all the extra features about the “finesse” bits – in other words how to recover from mistakes.
    And all the small details also look more clear in this version.

    Cheers to you all
    And wishes of plenty inspiration for upcoming videos and projects!

  8. Stunningly beautiful work! Your teaching method is also outstanding! And the videography is something to behold along with the sound quality. All of this comes together with great results as in all your work. Thanks for doing all you do for the people, bringing us all wonderful techniques to learn.

  10. When you are cutting the mortise, could you leave a 1/4″ section in the middle allowing you to use the jig while sizing the inner walls without needing to use the wedge to keep the joint from collapsing? This small section could then be cut out after the jig was used, and then trimmed to dimension as a final step.

    1. I think that unless you have a very straight vise and place everything well you’d probably end up twisting the mortise walls around that middle section a bit (personally I’ve yet to see a vise that is completely straight). The wedge supports nearly the entire mortise wall and would prevent that. That’s probably why Paul put it in so high at first and then gradually moves it down.

  12. Wonderful to watch the correction steps at the end. You may be slightly disappointed to have to make them, but to all of us out here, that is by far the most valuable and fascinating part of the lesson.

    Please make more mistakes for us in future videos!

    1. You could use a couple of magnets inside the similar jig to hold the saw in place, however the jig would have to be two different sizes—one for the tenon and one for the mortise to account for the saw kerf—any saw kerf.

    2. Hello Benoît, I imagine getting a clean sawcut that stays vertical would be very difficult without the back hitting the guide. You are of course very welcome to experiment and let us know, but it may be adding unnecessary complexity.
      Best, Phil

  15. Thanks to you Paul and to your great videography team. Wonderful video. I really like the finesse parts as they show how to correct those small and detailed errors we are likely to encounter in cutting this joint.
    Cheers,
    Michael O’Brien

  17. Paul, I’ve been using my routers as gauges as well after seeing you do it in other videos (also, the only combination gauge I’ve bought so far I sent back b/c I didn’t find it satisfactory, hope to get a good one someday). One thing I started doing when I can, i.e. when the distance isn’t longer than my plane blade, is have the blade mark the farthest side of the mortise from the face I’m registering the router against. This is so that the bevel of the blade is towards the waste wood of the mortise hole. I noticed you didn’t do that, but instead had the bevel towards the good wood outside of the mortise hole. Then again for the tenon I have the blade mark the line nearest to the registering face, as that’s where the waste wood is. For me, still very much a beginner, I felt I was able to achieve cleaner lines this way in the finished joint. But, it’s quite possible that’s only because I’m still too deficient in other aspects of making the joint. The only reason I thought about this when marking a mortise one day is because I started thinking of all the videos I saw you teaching your knifewall and its importance. I’d love to hear your thoughts on when it’s okay to not worry about the bevel being on the waste-wood side of a joint line. Thanks again for another fantastic video, I’ve learned so much from your videos and it’s exciting as I watch my skills grow.

  20. Paul, You showed how there is some latitude when assembling the joint so that you need to watch both directions to get everything to close up. My question is, if you are making up a four-sided frame, how do you clamp? It seems like clamp pressure could cause each corner to slide out of place. Do you just tighten up progressively around the four corners and tap things back into place as you go?

    2. Hi Ed, it is indeed a matter of applying the clamps evenly with two widthways and two lengthways, tapping with a hammer or using hand pressure to align them. When you have four corner joints of that size, it provides quite a bit of friction.

      Jim, I tend to answer the questions on WWMC consulting him where necessary with him commenting personally when we feel that will be of particular benefit. We aren’t online over the weekends. Paul is generally very busy with prototyping and developing projects, so we try and minimise his time directly answering questions on the computer in order to progress things as effectively as possible.

      Best, Phil

      1. Thanks, @filadams. When I say, “Paul,….” it really means, “You, lot,…,” but seems a bit politer. I appreciate the time the team puts into answering our questions. It makes a big difference in what we all get out of the presentations.

  26. Very nice. Here’s a possibly correllary question. My wife wants a clock with the symbols from the Elements chart (H, He, Li, Be, B, C, etc). I found one but it’s too big for a regular square frame. So I’m thinking of making an 8-sided frame. Can this tenoned miter be used for this? Obviously it can’t be done with 45-degree cuts. Any knowledge provided would be gratefully accepted.

  27. I would like to use a joint like this for a frame that I will be shaping. I am thinking that because of the shape I may need to make the tenon thinner. I would think that this would be fine but since I have no idea what I am doing maybe someone here could advise me on what I should do.

  28. The jig for paring down the mortises accurately should or could be made wide enough so that it could be clamped to the timber below the mortise. That way you would not have the problem of the mortise compressing.

    1. Hi Michael,

      Paul says:
      It would be better not to have the mitred joint and just to have the mortise and tenon joint.

      I used this in my personal shed build (you can see this in my vlog 014 on YouTube).

      Kind Regards,
      Izzy

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