There are certainly authorities here that know more than I do and I am sure they will contribute.
There can be a few issues that I know of that make cracks:
1. Many cracks come from the blank not being throughly dried before you turn and finish it.
Solution: make sure your blank is dry. Certainly not all purchased blanks are dried before they are sold.
2. Overheating the blank when it is drilled can make some woods brittle. Heat in general is an enemy of wood.
Solution: Take your time and back out the bit regularly to allow it to clean.
3. Not aligning parts during assembly can bring stress to hairline cracks that were waiting to happen. Not cleaning glue out of tubes before assembly can cause stress durning assembly and later.
Solution: clean and align and take your time.
4. Some woods are more prone to crack by nature.
Solution: unsure
5. And of course one of my personal favorites ...dropping the pen. I am an undisputed authority on this technique.
Solution: Don't drop it. Sounds easier than it seems.
Sorry about the crack it looks like a very nice pen.
That is a huge split!
I have had my Snakewood and Curupay (Patagonia Rosewood) crack because it is the nature of the beast. But, in the Snakewood you have to look for it even though the cracks are longer and in the Curupay they are fine, dark lines that do not look bad until the finish begins to fail.
