Drawbore tenon on outdoor contruction

  • Creator
    Topic
  • #132182
    kjellhar
    Participant

    Hi, I know this isn’t exactly furniture, but I’m guessing some of you may know a thing or two about it anyway. And after all, it is joinery.

    I’m planning on building a set of gates for the driveway to a cabin. This will obviously be exposed to weather, so I will use impregnated construction wood (pine). I want to avoid bolts as much as I can, and I don’t think I can rely on glue for this, so my thought would be to mortice and tenon the joints, and then use drawbores to keep them together. But I have a couple of questions:

    1. Should I use glue as well (the type that can stand water, like Titebond3 or something)? Did I mention that the cabin is up in the mountains. Lots of weather, but the gate will be taken down during winter time to avoid breaking it from the snow load.
    2. Do I make the pegs from the same wood, or do I need to make it from something stronger, like oak?
    3. Any other thoughts or suggestions?

    Cheers,
    Kjell

Viewing 15 replies - 1 through 15 (of 15 total)
  • Author
    Replies
  • #132201
    Matt McGrane
    Participant

    @mattmcgrane

    Kjell, I think you should try the drawbore technique on some sample pieces first. It could be that pine doesn’t do well with this method, but I don’t know for sure.

    As far as the peg material is concerned, my first thought is that is should be a hard wood. But you should try a couple different woods on the samples as well. Pine can be so soft that maybe a hardwood peg can split the tenon as it pulls the joint together.

    You may also try different amounts of “offset” between the holes in the tenon and the mortised boards. It could be that due to its softness, the pine needs a larger offset than a joint made from oak or maple.

    Sound like an interesting project. Have fun.

    Matt, Northern California - Started a blog in 2016: http://tinyshopww.blogspot.com/

    #132233
    jmahoney
    Participant

    @jmahoney

    I agree with Matt about the pine needing a slightly greater offset, too much though will fracture the tenon. As far as pegs go, grab some oak, the pin is under the most pressure, whole joint considered, so it MUST be stronger than the material it’s mating. TightbondIII is great, of course a little exterior liquid nail goes a very long way and is my go to choice. Mortise and tenon would be good, but don’t discount bridal joints.

    Best,
    John

    Perhaps I'm Just Over Eager, Better to Curb the Enthusiasm

    #132239
    kjellhar
    Participant

    @kjellhar

    Thanks Matt and John.
    I will not build the gates until spring, so I will do some experimentation during the winter.

    Given the choice of softwood or hardwood for the pegs, I think hardwood will be it. The pegs themselves can be made equally strong by making the softwood ones larger, but that will make the holes bigger, which will remove more material from the mortice and tenon.

    Also, and this is my own theory, when using dry oak for the pegs, and relatively moist pine for the frame, the frame will shrink more than the pegs, making the fit even more tight as it adapts to the environment.

    Kjell

    #132241
    jmahoney
    Participant

    @jmahoney

    Your theory is correct, that’s why a lot of timber frames go up green, wood contracts on it’s self, little extra tightness in the joint…yes, you can make the softer wood pegs stronger with more bulk, but compression is also a factor, im not sure if it’s significant enough that it would comprise the integrity of the pin…but you never know. also white oak just seems to be hands down the most popular pin material for anything structural requiring a drawbore tenon. Have fun with your project 🙂

    Perhaps I'm Just Over Eager, Better to Curb the Enthusiasm

    #132243
    kjellhar
    Participant

    @kjellhar

    White oak it is then.

    Thanks,
    Kjell

    #139546
    tenjin
    Participant

    @tenjin

    Hi,

    How did you get on with your gate?

    I am planning something similar.

    Regards

    Darren.

    #139553
    kjellhar
    Participant

    @kjellhar

    The project was a bit delayed, but the gates are ready, and I’m off to mount them the next weekend.

    I did not go with a drawbore tenon. I made a through tenon and inserted a straight peg to just keep it together if the glue failed. The bars are joined with e 2cm deep tenon and shoulder all the way around.

    I used 48*98mmm construction timber for the frame, and the bares are made of 22*98mm boards meant for outdoor decking.

    It came out around 20kg and feels rock solid.

    • This reply was modified 2 years, 9 months ago by kjellhar.
    • This reply was modified 2 years, 9 months ago by kjellhar.
    Attachments:
    #139584
    Craig
    Participant

    @craig

    Nicely done!
    Best,
    Craig

    SW Pennsylvania

    #139585
    tenjin
    Participant

    @tenjin

    Hi,

    That looks great!

    Thanks for posting the photos, it’s helpful to a new woodworker like me to see other people’s projects.

    Regards

    Darren.

    #139586
    kjellhar
    Participant

    @kjellhar

    Good luck. It’s easier than furniture since you will get away with a more rough finish.

    #139752
    kjellhar
    Participant

    @kjellhar

    So, that’s it.
    The gates are up and everyone is happy.

    • This reply was modified 2 years, 8 months ago by kjellhar.
    • This reply was modified 2 years, 8 months ago by kjellhar.
    Attachments:
    #139759
    piper
    Member

    @piper

    Just a suggestion to take your top j-bolt hinge pin and turn it over, so the pin is facing down. This prevents anyone from easily just lifting the gate right off of your hinges and walking away with them.

    #139760
    kjellhar
    Participant

    @kjellhar

    Hi Piper,
    I guess you live in a different part of the world than I. I would be shocked and surprised to see that happen on a very modest Norwegian mountain cabin.

    Also, we need to take them off during winter, or they will be torn down by the snow load.

    #139784
    piper
    Member

    @piper

    Well, if you have cows, a metal gate with both hinge pins pointing up allows a cow to hook a horn up under one of the cross posts and lift that gate right up off of the hinges.

    #139785
    kjellhar
    Participant

    @kjellhar

    Ahh, see your point, just sheeps around here.

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