Prototype Shop Step Stool

All the vertical pieces and side supports are 1 x 3 (ripped from 1x4) the seat is made from 2 pieces of 2x8 ripped to 7-1/2" and 7-3/8" then bandsaw out the leg notches. Two 1-1/2" wide butt hinges (or four 3/8" Oak Pegs), 2 - 1 x 6 x 16" long steps, along with glue and clear poly, complete the parts list. If you do not choose to hinge the front part of the seat back over the back half of the seat you can simply use pegs to hold it in position while sitting and remove it to use as a step stool. BTW: Hinging the seat's front half up and over the back half of the stool yields a nice flat surface to step on when using as a step ladder, other wise you'll have to step in one of the leg grooves. Calculating the radius for the two seat or leg grooves was interesting, I only knew the depth of the groove (.5") and it's width (6"). Think of the leg groove, from the front, as a segment of a circle with the chord as the straight line across the top of the groove. I guessed at the depth which in mathmatical terms is called the sagitta, and set it at .5", the width of the leg groove is 6", thats the chord length. Hence the formula: S = R - √(R² - (chord/2)²) Substituting: .5 = R - √(R² - 3²) This resolves to 9.25, that is if my algebra still works a little. I'll build one and see if my depth etc. is comfortable. I cut a template from 3/16" plywood then marked the edge of the two seat pieces. Next I made a square guide, and sawed the grooves on the bandsaw. If you use pegs to hold the front half of the seat (no hinges) you can make the leg grooves 6" wide, keeping the depth at .5" and width at 6".

SS1 frame being glued.   The top step is temporarily moved to the back to help hold the frame square while the glue sets.

view along the seat top showing the two sawed leg grooves.

Side of the frame.

SS1 with top step glued in correct position and back glued on.

From the back.

Ready to climb.

From left front quarter.

With seat down.   You can just see the 4 countersunk screws holding the back seat half on.

Another close look at seat front, you can see one hinge on the far side.   You can't feel the hinge when you sit.