Adjustable picture frame jig
If you've ever assembled a picture frame, you know the difficulties of creating seamless miters and a flat glue-up. Sometimes numerous clamps and an extra set of hands don't seem to be enough. WOOD magazine reader Dennis Parrot of Greenfield, Massachusetts, solved that problem with this adjustable frame jig.
Cut the base, braces, and corner clamps, as dimensioned in drawing. Our jig measures 27x32", but you can increase your dimensions for larger frames. The three braces across the bottom keep the base flat when applying clamping pressure later.
Glue and clamp the corner clamp parts together. The overhanging hardboard captures the clamp banding when using the jig later. After marking diagonals on the base to locate the slot centerlines, we drilled a 5⁄16 " hole at the end of each slot, connected the outer edges of the holes with straight lines, and cut the slots to shape with a jigsaw. Sand all the parts smooth and apply a clear finish. Later, secure a corner clamp to each slot with bolts, washers, and wing nuts, allowing just enough slack so the clamps can slide on the base.
To use the jig, place a corner clamp at each corner of the frame being clamped. Waxed paper beneath the frame corners prevents the glued joints from adhering to the base. Wrap a 1"-wide band clamp around the corner clamps and tighten, as shown in the photo.