First piece of furniture...tractor seat bar stool.

Made of 3" OD pipe, 16" harrow disk, square shank bolt, old s-shaped open ended wrench, forged 3/8 round stock, and a piece of 1/4" plate. The gap is meant so the seat swivels without complicated/expensive hardware. Also, it allows a wrench to adjust/remove the seat if needed. If this barstool was at...say a bar, the gap would be invisable as it would face the bar.