Splined mitre joints are strong

Showing the strength of a splined joint


This for those who watched me making the moulded and mitred joint. A few weeks ago I experimented with the strength of the mitre joint to show the increased strength of my splined mitre joint. At both the Baltimore and Springfield shows, I made a hand cut mitred joint and jointed the mitre with two dovetailed splines let into saw kerfs from my dovetail saw. This cinder block is solid, not hollow, and so weighs in at around 40 lbs. You can see how uniquely strong the joint is. By moving the string along and increasing the leverage it eventually broke, but I am amazed how strong this joint really is.


  1. Chris Wong on 22 January 2012 at 8:47 pm

    Clever way of demonstrating the strength of the joint.

  2. Paul Sellers on 23 January 2012 at 7:56 pm

    Hello D.J.
    Re a finish nail usage. Sometimes it’s necessary to use a finish nail as a permanent method of ‘clamping’ until the glue sets; and there are places for finish-nail fixings.Here is a trick I use for frames that stops splits and give a good connection that lowers the risk of mitre slippage during nailing. Cut the head from the nail and install it in a drill – hand, electric or battery drill. Drill the mitred piece in place so that you drill through the first mitre and into the end grain of the second but not full depth. The four-sided nail point on any nail will drill a perfect hole by reaming the wall of the hole and leave good friction on the wall too. The entrance into the second mitre is enough to prevent slippage and guide the nail on into the wood. This works for applying beading to the face of wood or things such as corner bead and moulded stock. I’ve used this method for 45 years. It saves drilling out too much and gives good bite too.
    This is an alternative to situations where splines don’t work or are not suited or appropriate such as regular moulded stock with paint or gilding on it.

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