I found a bowling ball at the Salvation Army resale store, it had a chunk broken out of one of the finger holes. It was marked $5, I asked about a discount since it was broken, the lady said it was free. I like to support the Salvation Army, they do a great job with our local homeless. So I gave her a $10.
To cut it in 2 parts, I turned a peg to fit a finger hole on my lathe and left the square end of the blank. I then jammed it home with some epoxy and mounted the square end in a vise. Then I used an old handsaw to slice off about 1/3 of it. For my vise on the top I drilled and tapped a hole to fit my wood lathe chucks. I took a piece of 1-8TPI all thread and epoxied it in the hole. When i use it I screw on one of my chucks.
If was younger, I would make one of these. But since I am crippled up and don't get much shop time anymore, I don't need it. I may not need it, but I sure do want one. I found this looking on the internet, and have saved the picture for over a year.