Simple Corner Clamp Jig




Introduction: Simple Corner Clamp Jig

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In my last build, I made a really large wood picture frame with splines and I thought I'd share how I made a super simple jig to clamp and align the corners during the glue up process.


Watch the 2 minute video or read on!

Step 1: Mark Your Cuts

These corner clamps or extremely simple to make and even more easy to use. Start with a scrap piece of 3/4 inch thick wood (mine was about 10 x 7).

Mark the piece of wood so you have 4 equal squares.

Then within each square use your speed square to draw a triangle on the outside edge of the square.

Step 2: Drill Relief Holes

Where the triangles intersect, drill all the way through using either a Forstner bit or spade roughly 3/4 in diameter (it can be a bit bigger or smaller. The important thing is to make a hole all the way through.

These holes will serve as relief pockets and prevent the jig from interfering with the corners of the frame.

Step 3: Make the Cuts

Head over to your miter saw and set the blade to 45 degrees. It is very important that your 45 degree angle be accurate, otherwise the inaccuracy will carry over to your frame when clamping, and the whole frame will be out of alignment!

Tip: Use a scrap piece of wood and cut a miter. Butt the 2 ends of the cut together to form a 90 degree corner, and check it for accuracy using a carpenter square.

Cut along all the lines you traced, starting with the 45 degree cuts, then set your miter saw back to 90 degrees and make the remaining cuts.

Step 4: Glue Up

The corner clamp jigs are ready to use! Lay your frame on a flat surface and line up the corners. Gentle press the corner clamp jig into place and use a quick clamp to apply pressure. Don't overdo it- excess force will force the frame out of alignment. Moderate pressure should be sufficient. Oh, did I mention you should add glue before clamping? ;)


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    14 Discussions

    This is a very nice idea! Thank you for sharing.

    oooh... these are awesome! Fantastic for my newbie projects!

    Really appreciate the share & super simple instructable!

    Thank you & keep up the good work


    8 months ago

    Hmm, never seen this version of picture frame clamping, doesnt the inside corner triangle push the joint apart?

    4 replies

    My thought too. I'd add that the clamps really aren't really helping to hold any glued face together---that is none of the forces are perpendicular to a glued face.

    "Don't overdo it- excess force will force the frame out of alignment. Moderate pressure should be sufficient."

    Been using these for years. The only way you can beat one of these for versatility is a band clamp.

    It would if you used only one, but when these are in all 4 corners it doesn't.

    Even commercially offered clamping jigs are of this general design. The angles are/provide the 'inward' pressure to the mitered faces and the smaller triangular piece merely provides a surface for the actual clamp. There 'outward' pressure exhibited is negated by the outside pieces, due in part to the 'relief' hole. As with any clamp, if used incorrectly, the joint will be sloppy at best.

    I've been using jigs almost identical to this for many years and as long as I assemble everything properly, paying attention to details, I've achieved success every time.

    Very cool! I would almost make a groove on the outer edge of the corner clamp jig so I could hold the frame together more tightly.

    Thanks for the idea, I will make them tomorrow!

    Greetings from Amsterdam,


    Well thought. Thanks!

    You must be sighkick! I saw tour PF w/S Video and took note of your corner clamps last week with an eye to building myself a set.

    Last night, I sketched them out from memory but did not go further given the lateness of the hour.

    Having made a set that required two clamps for another project, I thought this design elegant - possibly with the addition of some fine sandpaper along the gripping edges - or thin rubber for clamping finished work. Planning on experimenting with those ideas as my mitre saw's not the most accurate tool in my shop!

    Thanks for thinking of me!

    So simple, I never even thought about this. Many Thanks for the heads up

    Great! I've seen pictures of things like this in use before, but not how to make them. Thanks!

    Quick and simple. I like! Need to make some for a project idea.