Been making Christmas presents. I was working on a beautiful piece of walnut - that I saved from the firewood pile! I'll post pics when done. I've never seen black walnut like this. Maybe it's a hybrid.
I was making a box. Finished it will be about 2.5" in diameter and 6" tall.
Bottom is done, except for the joint. Was turning the lid down, when I just started losing focus and the lid got blurry.
I stopped because I didn't want to ruin it.
In retrospect, fainting into a spinning lathe with a sharp tool in my hand could have been ugly. 'Course, some part of my brain said "Finish it! You have 3 more to go."
I was getting very close to the finished diameter and was really in the zone. Beautiful surface. I've never locked my knees before, but I think that's what happened today. I went upstairs and laid down for awhile. Blood flowed back to my brain, and I felt fine. Locking your knees cuts off circulation - that's why people faint.
So, remain aware of your body. Shift your stance a bit, even if you're working on a small piece where you can just rotate your body.