Here's just a small part of a big kit order from Sirius Rocketry.
All the couplers and tubes in the re-designed Odd'l Break-Away kit are hand cut.
These are longer than the available 1" couplers. At 1 1/4" long the segmented rocket stands straighter on the launcher.
This is only 11 sets from the 25 kit run I put together.
That's a whole afternoon of measuring, sanding and cutting.
I wore out a few razor blades in the process.