Thanks for comments.
I know snakewood is bit difficult wood. This was one of the first cigar pen I made, so it stayed for some time (and still is) crack free.
I tried to be very careful.
My teacher uses snakewood for making guitars, both as binding and fingerboard/bridge and also sometimes for sides and back. Bending involves high temperature and water (both what snakewood doesn't like), still the guitars are ok many years later.
I think for turning/drilling the high speed and removing too much material is first part of the problem where the blank may explode from heat then the finish that doesn't seep deep into wood is second, probably bigger problem. Wood turners would use someting like friction polish - that doesn't go deep to the wood, just create thin film on surface.
I (and my teacher as well) use french polish and you first start with very diluted shellac that rather seeps into the wood then work it toward full strength shellac with time. I think this plays significant role for the stability. The snakewood get sort of partially stabilized.
Now I didn't do french polishing using same lenghty process like making a guitar, just sort of quick version, but still I kind of feel this may be the "secret" of stable snakewood. And also it stays candy-like shiny for a very long time.
Anyhow, I think for the price and possible problems there are better woods. I like my snakewood pen, but from the comments of friends the snakewood doesn't get that much attention. For example the red amboyna (4th from left) get far more comments from friends.