How-to: Strengthen your Mitered Frame Corners with Easy Splines

How-to: Strengthen your Mitered Frame Corners with Easy Splines

You’ve seen these I’m sure. Little keyed pieces of wood on the four corners of frames. They’re called splines, or splined miter joints. Just knowing what they are called is half the battle. Sometimes builders make the keyed in wood a radically different color so they stand out. They add a lot of strength to your corners and are easy to do. You will need to do a little pre-build first, but once you make this easy wood jig you won’t have to do it again. Thank you Kevin Wilson for turning me onto this easy jig. I hope it demystifies it for all of you. So here’s what you do, let’s watch his video first:



Build the jig from 34 ” MDF or scrap pine. Bevel one end of the rear cradle at 45-degrees, then glue it to the upright at a 45-degrees angle to the bottom edge of the upright. As you glue the front cradle in place, check that the two cradle pieces are 90-degrees to each other. It’s nice to reinforce these glued in pieces with screws from behind.

Next, cut the pieces for the saddle. The saddle fits over the tablesaw rip fence without any play, but still allows the jig to slide smoothly. When attaching the saddle, the upright/cradle assembly should rest on the table of the table saw. You could use a little ultra high weight molecular tape to increase the slickness between the sale and the rip fence. Just make are you accommodate for the extra 1/64″-1/32″ the tape takes up.

To use the jig, make a mark on the bottom of the corner receiving the spline to indicate the depth of the cut. Place the frame in the cradle, and raise the blade so its highest tooth just touches that mark, as shown in the photo. Slide the jig back from the blade and reposition the rip fence to cut the kerf for the spline. You’ll notice a quick spark in the video. This is a-okay unless you have a Sawstop table saw. IN which case you’ll want to make sire you turn off the safety system or else you engage you $100 emergency stop cartridge.

Have fun with it ya’ll. Increased strength and good looks, even if you use the same wood type, they loo great. Do you use this system? Do you use something else? Let all of us know in the comments…


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