After mounting a drill chuck on my lathe, I made a small wooden knob as a demonstration piece. Peter Brown suggested that it looked like a "tippe top" (the inverting top, like the one shown at left). So I tried the knob as top, but it wasn't the right shape..
I tried tweaking the shape on my belt sander, and eventually I got it to the point where it would invert, though by that time it had little resemblance to the knob I started with.
I thought it would be a fun thing to try to make a tippe top on the lathe. I started with a block of crabapple wood as a blank.
I first turned it into a cylinder, Here pressing the chisel against it to check if there are any flat spots.
The body of a tippe top is roughly spherical. I made a guide, like I did when I turned this sphere to guide me with getting the radius just right. I made the guide by drilling a 1 1/4" hole in a piece of hardboard.
Here just eyeballing it to get a sense of how much more I had to take off.
Part of the sphere gets cut off to form a sort of mushroom shape
It helps to hollow out a bit under the mushroom to lighten the underside. The center of mass needs to be away from the handle.
Getting close to final shape, with the parting tool
Then parting dangerously thin near the head. After taking the workpiece out, I cut off the end with a flush trim saw.
I then switched the lathe over to use the drill chuck in it.
I chucked the top by the handle, with some paper wrapped around it to keep the chuck's jaws from denting the handle too much. With it spinning, I sanded the end of it smooth. I had to keep moving the sandpaper back and forth to sand the very bottom because the spinning motion doesn't cause the wood nearest the center to move very much.
An important property of a tippe top is that it's self righting. That is, if held tipped, and let go, the top rights itself to handle up. The same physical properties that make it invert while spinning are the ones that make it self-right when not spinning.
Testing it, the handle was still a little too long, so I shortened it.
Tippe top spinning, after it inverted itself. The top is started like a regular top, but as it spins, it gradually inverts and stands up on the handle.
Here's what it looks like. I sanded the edge to taper it in towards the handle slightly, which made it work better. I did that on the belt sander.
It takes a bit of practice to get it to spin fast enough to have enough momentum to complete the inversion maneuver. Because the top is round on the bottom, if it's not spun exactly vertical, it will scoot off to the side, especially under the couch!
Baby Harriet found this experimenting with the top very amusing, and swatted at it whenever it got near her. But everything new to her, so the inverting thing is lost on her. A tippe top is more of a fascinating toy for adults and older kids.