The lip on the shelf holds the sawhorse rigid. To break down the sawhorse, simply lift the shelf.
#656 Shopmade Multi-Joint Jig - Joinery Tips, Jigs and Techniques
The easiest cross cutting sled you can make that still achieves accurate cuts.
Simple Center Finder
Box Joint Techniques - Joinery Tips, Jigs and Techniques | WoodArchivist.com
General purpose crosscut sled (and an announcement)
Box Joint Jig Handles Drawer Joinery with Ease
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