You seem to be off to a good start with segmenting and pen-making in general !!!
And it seems you already have a band saw .... I am admiring especially your third pen above and trying to imagine how you did it so beautifully !
If you are in the mood to spend some money on tools, I suggest you consider a Byrnes miniature table saw .... extremely useful ! . Check out the other Byrnes machines as well. . I can't remember the website right now, but a Google search will get you there.
They are the best in their class, IMHO.