Mark,
Thanks for your reply and the detailed pictures. . General idea I get.
A thing I don't get is ... when you do the longitudinal slitting, the adjacent slits seem to meet near the axis of the main dowel which is being slit. . And if the slits meet, the wedge-cross-section piece in between the slits would fall out ! .... or does the wedge-cross-section piece still hang in there in an extremely fragile and precarious way ?
OK, Got your query Mal.
YES, I have had some slotted blanks that failed due to what you described.
For the 3-inlay blanks, I can cut a slot about .25" wide, to a depth to insure the final OD of the pen is intact for the design. That will leave enough material for the inside triangle (Picture to follow) for it to be good. However, I cannot cut a .25" slot on a 4-inlay blank. The inside depth is too great and the pieces fall apart (not a good description, but the result is bad).
So... going to a lesser width of the inlay, .240, .230, .220, etc.. We have more options to go for a 4, 5, 6 slotted inlay. When I go to the trim rings, I can cut my slots for a solid or 3-ply inlay very thin; probably .0625+. So things can get interesting.