Hi Michael, welcome to the vortex of segmenting.
When you say "glue-up", are you referring to
constructing the basic brick which you are then cutting into slices, or the process of
constructing the slices into patterns (rotating for the checkerboard)? Each has a few challenges.
There are a wide variety of UTube videos and online tutorials with different methods. I don't have a favorite personally.
If you indicate which step you are not happy with, more specific suggestions can be made.
For the Celtic Knot procedure, I'll let others give suggestions as this design I have little experience with (although I use a 45 degree sled for several machines for many of my segmenting).
These are some great examples:
https://www.penturners.org/threads/a-few-8-loop-celtic-knots.157471/
fixed scrool down
www.penturners.org
This is another pen in my black and aluminum series pens. This is a Sierra Vista chrome kit with a black acrylic and an aluminum knot. Spun and polished to a high shine. Thanks for looking. Any questions or comments feel free to post.
www.penturners.org