Model rocket cradles are used to hold a rocket while you're working. This versatile design allows the size to be adjusted to fit the length of the part.

The small version is typically used for low power rockets, with the larger version being used on larger high power rockets.

I used dowels for the small version, and PVC pipe for the large. You can edit the design in Fusion 360 to match the size of whatever material you have on hand. I've used 1/2" wood dowel and 1" PVC pipe respectively.

You can see more here: https://www.youtube.com/watch?v=KZOP-TzS-5M