I was in need of a step ladder to get at lumber on my lumber rack and some floor to ceiling shelving I have covering one wall of my shop. While looking for some decent designs, I can across several designs for something called a Franklin Chair. Sure enough, I then located several here as well. My design is based on several different ones I saw, with my own design for the chair back.
Given this is strictly for shop use, fine furniture was definitely not the end goal. As such I made this thing entirely from 1x4 select pine boards from the big box store. The only other part of note is the piano hinge I used. Finally I put a couple of coats of spray on poly-urethane just to seal and protect it.
This perfectly suits the needs I had for the shop. It provides a perfectly sized step ladder AND converts to a chair otherwise.