How to prevent calluses from writing on chalkboard? I just finished my first semester teaching (I lead two recitation sections for pre-calculus twice a week). It went well, but I've noticed a sizable callus has formed on my right middle finger on the left side between the nail and first knuckle. This is from how I hold the chalk, I believe. The callus is rubbing against my finger when I write now and causing a bit of pain.

How do I prevent this callus? I don't have much experience with writing on the chalkboard so I imagine this is from holding the chalk incorrectly. Maybe someone knows secrets to the chalkboard that I am not aware of?
A couple ways. You may consider products called "chalk clip" or "chalk holder" like this one:



They make the girth larger and less likely to produce a small pressure point on your finger, which causes callus.

Another option is to get some "foam tubing" from general hardware stores. They are cheap and in different sizes, thicknesses, and even colors. Cut a 2 to 2.5 inches long segment and put it over your middle finger. To improve comfort when bending your finger you can make a small vertical incision on the tube (palm side) so that you can bend the finger more freely.

Volleyball players also have elastic finger guards like these:



You can get a set of them from sports stores. Just pull it down a bit to protect your last joint rather than the middle joint. My experience (as a volleyball player not chalk writer) is that the ones with nylon outside and a thin foam layer inside work are the most comfortable.

If technology permits, you can also consider projecting your hand writing using a projector, computer tablet, or even interactive screen. Those methods allow you to write with a lighter grip.