I continued to struggle with this project because I felt very strongly that I was onto something, but I just couldn't get it right. I can't design anything without making a prototype or, in the case of this shop stool, multiple prototypes. It was getting really aggravating. Then Gerry made a comment on my last post:
Even though I didn't want to do exactly what he suggested, Gerry's comment was the insight I needed and I knew immediately what I did want to do. My prototypes taught me that my ideal stool would have the wooden bicycle seat mounted on a long thin stem and Gerry's idea was that it should be attached to a heavy round object at the base. I retrieved a 10 lb. weight from my weightlifting machine, drilled four counterbored holes in it, cut off two short pieces of 2x4, grabbed a scrap of closet rod, drilled two 1 1/2" holes and there it was, exactly what I had been groping for all this time:Andy: How about a circle for the base, with the seat pedestal set to one side. If the base was 1 1/2 -2" thick you could ease the bottom front to accommodate rolling forward as well as right and left. A dense hardwood might give the weight needed to keep it upright.
I know this is arguably ugly, but it works great and does have a certain modernist appeal. You really have to work at it to knock this stool over and the rounded edge on the weight lets it move easily in all directions. It's very comfortable and allows a wide range of movement.
This one doesn't incorporate height adjustment because I knew exactly how high I wanted it to be, but it wouldn't be difficult to add. I am not sure if this is a coincidence, but the height I chose by feel is exactly 1/2" less than my inseam. The important thing is that your knees be slightly bent.
This sort of active stool, as I have called it, is obviously not for everyone. The bicycle seat is ideal because you can move around without sliding, but you probably have to be a bicycle rider to appreciate this. For me, though, it is the ideal shop stool, just what I wanted.
I look at it now and can't understand what took me so long. Now that I can see it, this design seems so obvious that it is almost embarrassing that I floundered around.
I am done.