I have an Estie Dollar which is beautiful... other than a crack in the threads on the barrel.

How stable are these, typically?

I usually do not shellac the sections if I get a tight fit, but I figure that on this I might just re-sac the pen, and then shellac the section in place (after testing) to hold it all together and try to control the crack.

Thoughts?

Well, it depends on how large the crack is. I have a couple of Esterbrook with cracks in the threads and they do just fine. No shellac needed. I would try it without first and see how it goes before you make it difficult to remove further on down the road.

Best-
Brian