Summary

A customizable jig for aligning and gluing a variable number of fins onto model rockets.

The STL uploaded here is for a BT-50 body tube and 3/32" thick fins.
If you want to use the Customizer to make a different size, these are some useful Estes rocket tube diameters (Ref: http://www.estesrockets.com/):

Inner diameters:
BT-5: 13.2mm
BT-20: 18.0mm
BT-50: 24.1mm
BT-55: 32.6mm
BT-60: 40.5mm