I built this artist’s easel back in 1983 and just did an SU model, in case I want to build an updated easel.
Introduced a few inventions including a canvas holding system that allows brushes to flow over the edge of the canvas (stretcher bars are gripped by stainless steel pins from the back of the canvas) and a fly wheel / foot operated raising mechanism.
Also includes a tempered glass palette with a neutral grey background - paintings can raise and lower behind palette. The base has a torsion box design to add rigidity.
Oh, yeah. No wing nuts on the back struts either, now that you mention it. I’m not throwing stones; I have more unfinished stuff than I can shake a stick at.