This is a Jig I finished last week and published it on my Youtube channel.
I was in my shop as normal making my wooden boxes and picture frames and cutting splines in the using my Biscuit Jointer as I normally do. I thought to myself I must make a Jig for this process so that it will make the jointer more stable. That's what I did and it works great and I can adjust for different height boxes by adjusting the front Jointer lip and or adding or removing the wood spacer. I can also use this jig for Oblong type boxes or complete square ones as well as picture frames.. There are two types of clamps that I use on this jig one for oblong boxes and the bird beak type clamp for the completely square boxes and picture frames.
Once it was all complete I tested it and it worked Great, So pleased with it and helps me out a lot with all my boxes and picture frames.