I saw this in "Ken's favorite shop tips" in The Family Handyman April 2014.
When mounting corner blocks to reinforce a frame or case, use a clamp block on the outside to provide a flat surface for secure clamping and to prevent damage to parts. For example, to mount corner bl
Learn how to cut and assemble your picture frame moldings using a specialized sled and 90-degree corner clamps.
DIY Vise Clamp 90 Degree Corner Clamping Wood Work Bird House | eBay
In this video I make a corner clamp out of a couple of squares. The idea here was to have something that I can use to clamp 90 degree angles with. I looked i...
Universal Fence Clamps with Clamp-It™, Special Offer!
Jig to assist 90 degree corner clamping.
tips to make clamping dogs for making picture frames
IRWIN Tools QUICK-GRIP 90-Degree Right Angle Clamp (226410) #DIY