Making Half Lap Joints:
Wood Joinery Made Easy for Building Furniture, Building Fences, and More
© 2008 by Kelly Smith all rights reserved; content may not be copied, rewritten, or republished without authors written permission
Every woodworker and finish carpenter has his or her favorite member of the wood joinery universe.
But it's important to have a mental toolbox full of them. The half lap joint is one of the simplest
(much easier than making dovetail joints
lends itself to furniture making.
Basically, this joint is used to mate two pieces of the same size stock. It can be used to mate
right angles or when joining two boards in continuous runs where strength is more important than the
good looks of a miter.
Tools to Cut Half Lap Joints
There are many ways to cut half lap joints and the method employed depends on the size of the stock.
For larger projects where the stock is at least two inches in either direction, I like to use my
table saw with a stacked dado set.
For smaller stock, a router table works well. For very small work, such as model construction, I
like to cut them by hand with a coping saw. The thinness of the blade allows for precise, slender cuts.
Other possibilities include a radial arm saw or a miter saw. If you're really in a pinch, even a
circular saw may be used. You'll have to set the blade depth, cut out slices, and finish by using a
hammer and chisel to knock out the scrap.
If it involves wood, Rockler has the tool!
Setting up and Cutting the Joint
First, determine the width of the cut and set up the dado set and mount it on the saw's arbor. It's
important to get the blade cutting depth exactly right. Use a scrap piece of stock that is the
same dimensions as the project material for this step.
Once you've got the proper depth set, go ahead and make all the cuts that you intend to make. Proper
set-up usually takes the most time on most projects; you only want to do it once.
Assemble and Finish the Project
Just like any other joinery technique, the first thing to do at this point is to make a dry fit
and make any fine-tuning adjustments. Then, spread your favorite glue (I'm becoming more and more of
a Titebond devotee all the time) on one of the pieces and mate them up.
Once both pieces are perfectly aligned, clamp it up and let the glue cure. I almost always put wax
paper between the wood and the clamp jaws. Also, I put some on my workbench under the project. This
eliminates squeeze-out problems.
When the glue has dried, I like to drill through the joint and glue in a piece of dowel. It lends
additional strength and if the color of the dowel is different than the color of the wood, it
gives the projects an interesting look.
Now, simply sand and finish as usual!
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