I just added a M6 nut inside of the Guide from GreaseMonkey88s Rod and Tube Cutter for Dremel (Thanks a lot for this Design!).
I added a wing nut on the bolt to change the height without tools.
I also made a version based on rckabs Rod and Tube Cutter for Dremel Flex Shaft for the flex shaft, because my Dremel 4000 ist to fat and touches the base.
I use it to cut the outer shell of stainless steel microwave coaxial cables and I needed something to limit the cutting height.