Some background. Last year, I fell into penturning. I thought hand-made pens would make nice gifts and I'm to an age where people around me are retiring from work. I liked the idea of getting a tangible result in one or two days of evening effort. I already had a lathe, an ancient 1947 Shopsmith. So, with the help and advice of the enthusiastic denizens on the International Association of Penturner's site I got the paraphernalia associated with turning pens, the bushings, mandrels, calipers, blanks, polishing compounds, finishes, pen hardware... It's a slippery slope and I have gone down the decline into the abyss with a jet pack on my back.
I made several wooden pens and wanted to try some resin but was looking for FREE resin. So, I asked my good friend Melissa if her husband Mark (a bowler) had any old bowling balls. She answered enthusiastically in the affirmative. A day or two later I got a call from her around lunchtime. "Dude" she said, "Go out and look behind your car." I looked out the side door of my office building and found a purple bowling ball behind the left rear wheel of Moby 3 (aka Mobile Solar Kiln 3). This was a urethane 'Hammer' ball with a real thick mantle and I got some good blanks out if it. It made nice pens - as an experiment, this worked out well.
So, Melissa called me a few months ago and asked if I could make some pens from a ball that once belonged to her husband's (deceased) grandfather. The grandchildren had very little by way of effects from the grandfather and pens from his old bowling ball looked to be nice mementos. I said, "Sure! No problem!"
Well, the ball turned out to be a real old one made of some sort of cured rubber composition commonly known as ebonite. I managed to wedge and glue a dowel into the thumbhole and clamped it into the end vise on my cabinetmaker's bench. I cut some chunks out of it with a hand saw. A Disston #12 because I am after all a Galoot, an OldTools guy, and don't own a Sawzall or the like. First thing I noticed was a strong, burning-tire odor even with just the hand cutting. This was a totally different animal from the urethane ball. Oh yeah. This bad boy had Presence. All progress stopped until I could order and install a 0.3 micron bag for my dust collector. I had a feeling I would need it.
Cutting up the ball:

After laboriously cutting some blanks, and burning up a bandsaw blade, I drilled out two blanks and tried to turn a couple of pens. The stuff almost instantly dulled any lathe tool I put on it (not to mention the smell). Unbelievable. The best I could do after dulling several turning tools was to just get the square blanks rounded, much less reduce them to the required diameter.
The best I could do with the ebonite after considerable effort:

A friend I know at Gore later told me those old rubber compositions for uses such as bowling balls were often filled with stuff like marble dust. That, plus the deformation of the rubber around a tool edge would explain why it was so hard to turn. I related this to Melissa and she was very understanding, said I gave it a good try but I could tell she was disappointed. Yep. Plus, the family had paid me some money for this. I had an overall design scheme in mind for the pen hardware and had already purchased it. I was committed. I was going to make this happen.
Ok, I decided to try the old ebonite as an accent ring with some sort of acrylic. The penturners at the IAP site often add segmentation to blanks with aluminum as a spacer. I cut some aluminum from old diskette shutters and glued up some blanks with a (mostly) black acrylic.
A segmented blank, ready to turn:

The acrylic was hard on my tool edges but I could turn it, although even that bit of bowling ball ebonite was a stubborn little nub on the end of the blank. Jeez. But I could see that this was going to work. I decided on chrome/black hardware and black acrylic for Mark and his brothers, gold/black hardware and dark amber for his sisters and platinum hardware/ smoky-gray acrylic for Mark's Mom (who was paying for this and wasn't expecting a pen).
Prototype blank turned to final diameter:
Melissa knows me well enough to understand that I need some deadline pressure to get off the mark and get 'er done. She called me up and asked if I could deliver some pens by February 16, for some sort of family gathering. With great relief, I delivered them on February 8. Here's one of the black-on-black pens.
According to Melissa the family liked the pens. I'm glad. It was fun, it was a learning experience, it was stinky.