Model Rocket Launch Rod Cap

This is a cap to put on your model rocket launch pad. It's got a stepped hole inside for 1/4", 3/16", and 1/8" launch rods. 1/8" is the common size that comes with starter kits by Estes, for example. I've played with the hole size a little bit and the current size, printed in PLA, is a snug fit after you work it on and off a few times. If your printer prints inside holes without shrinking them as much as mine, you might tweak the values in the OpenScad file to make them tighter.

The holes at