JIGS #1: Jig for corner keys

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Since this seems to be the week for jigs, here’s one I made recently for corner keys in boxes and frames. There’s nothing fancy about it but it does work quite well. I used some recycled materials and wasn’t all that precise but it does the trick.

These are often referred to as Spline Jigs but splines, I’m told, run the length of the miter on the inside edge and hold the corners together. I don’t use a jig when I make them. I just set my blade low and tilt it to 45 degrees. I make the spline the same 1/8" thickness as my saw blade. Spline material should run cross-grain for strength but when I miter long grain corners (e.g., stiles on corners of cabinets), I use it long-grain since I only use the splines to align the corners while assembling and not for strength since the long-grain glue-up of the stiles is sufficiently strong (in my opinion). Perhaps if I had used splines to align the corners of my last box, I wouldn’t have had such problems! LOL

Comments, suggestions, and critiques are always welcome. This is the way we learn!


-- “Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety.” Benjamin Franklin

  • Part 1: Jig for corner keys

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Brian, you did go through much more work than I did and yours appears to be made much more precisely than mine. I didn’t figure absolute precision was necessary and my so-called 45-degree angles didn’t make a perfect 90 but it still works! LOL

Abbas, the lines on the face are just scratched into the finish and help to figure out where I want to place the project to be cut. If a key needs to be centered, it makes it a little easier. The lines are approximately an inch apart but aren’t perfectly accurate either but seem to be good enough not to be noticeable in the finished project.


-- “Those who would give up essential Liberty, to purchase a little temporary Safety, deserve neither Liberty nor Safety.” Benjamin Franklin

The stops are a great idea. I wish I had done that. I plan to just use clamps and a piece of scrap for that, I also like the way you built the sled. Far less complicated than mine. Why the heck didn’t you post this last week? LOL

-- Losing fingers since 1969

Very nice. I have mine splayed out on the bench, waiting to assemble. It’s very similar, but now seeing yours I will be adding the stops. Thanks for sharing. I also incorrectly call it a spline box jig, but hey it’s what I will remember.

-- CHRIS, Charlottetown PEI Canada. Anytime you can repurpose, reuse, or recycle, everyone wins!

Very nice. Yeah i messed up the one i started building a while back. Tossed it and haven’t attempted to remake it. Someday. I have to many big projects going on right now. But yours i like.

-- Jeff Vandenberg aka "Woodsconsin"

Very functional.
I like how you run your blocks in shop cut track. I used to have a bit to cut T-track but gave it away to a friend.
The stop blocks are a must in my opinion as they prevent the piece from shifting during the cut and also position accurately.

I assume the vertical lines on the faces are reference line for positioning.

Well built.

-- Abbas, Castro Valley, CA

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