Knee Brace Tenon and Mortise 1 1/2″ Layout

Knee Brace Tenon and MortiseThis is an exploded view of a 3″x5″ knee brace tenon and mortise,  with tenon layout of 1 1/2″ off the face and 1 1/2″ thick, and its mortise in a tie beam.
The peg is 3/4″ in diameter and it’s placement is 1 1/2″ off the shoulder and 2″ off the bearing end.
The tie beam has been rotated 45° so you can see inside the mortise.

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5 Responses to Knee Brace Tenon and Mortise 1 1/2″ Layout

  1. Alec Mann November 8, 2016 at 10:39 am #

    Is it necessary to have the housing cut out to fit the full size of the brace into the beam? Or could you get away with just mortissing out for the tenon?

    • Brice Cochran November 8, 2016 at 5:47 pm #

      You can omit the full housing but I would not recommend it as a general rule. The housing adds a lot of strength to the joint and it hides the gaps in the mortise as the timber dry.

  2. William H. Cary June 15, 2017 at 1:34 am #

    Do you offset the holes for the pegs in the mortise and the tennon and by what amount ? 1/8 inch?

    • Brice Cochran June 15, 2017 at 2:12 pm #

      That is called draw boring and it is not always recommended to do. If you are using oak or equiv. you can do it but if you are using a softwood you have a good chance of blowing out the mortise rendering the joint useless.

  3. Jim Rogers June 15, 2017 at 2:19 pm #

    Braces have been found in old barns without any pegs at all. Braces work in compression. It is very unlikely, in my opinion, that you’d blow out the tenon with a 1/8″ draw bore in softwoods.
    I do draw bore brace peg holes. But I do it in two directions to help pull the brace to the housing and to the bearing end.

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