Mortise-and-Tenon Baby Crib with Lower Stretcher Frame

Four square corner posts receive guard rails on all four sides, top and bottom, with evenly spaced vertical slats tenoned between them. Slat spacing is solved automatically so the clear gap never exceeds 60 mm for infant safety. Every rail and stretcher is a straight bar whose body stops at the post inner face and whose ends are reduced to shouldered tenons that plug into clean rectangular mortise pockets in the posts; no member is notched against another, so the parts stay simple to machine. The two perpendicular tenons meeting in each corner post have their depth clamped so they never intersect. The mattress base is a row of wide planks running front-to-back; the two long bottom rails are made thicker (with correspondingly larger tenons) to carry them, and each plank's two ends seat into a matching pocket cut in the inner face of these rails, so every board is captured along its length and across its width rather than resting loose on cleats; a lower stretcher frame ties the four posts together near the floor. Every mortise and pocket is cut 1 mm larger than its tenon, giving all the joints a consistent 1 mm assembly tolerance. No metal fasteners are required.