Laying out the mortise for the leg
The Haunched Mortise and Tenon may seem like an unorthodox joint, but it is superior to just a regular mortise and tenon because of it's ability to prevent cupping on the rail.
Be sure to have the top of your legs square before starting layout.
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| The mortise detail in the plans is 1:1 so lines can be checked and transferred right off the plan |
First lay out the bottom of the haunch at 5/8'' and mortise at 2 7/8" from the top of the leg.
do so on two sides, this will be the corner of your leg that faces in
Next find the center and lay out 3/16" on either side. This will center the 3/8" mortise. You can also transfer these line right off the plans
Use the proper tools to lay out. this combo square in your toolbox is also a marking gauge. Lines should be paralleled off the edge and never drawn perpendicular from the end.
Do so on both sides.As a matter of fact do so on all four legs
Now layout the depth of the haunch. it is 3/8"
The shaded part represents the visible portion to be mortised out on the top of the legs
AKA: the Haunch
The rest of the mortise is not visible from the end grain.
the portion left on the top of the leg and not machined out solidifies the joint. Not only does it prevent rail cupping but it will also prevent the leg from splitting along the grain due to racking pressure.
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