Couplers for 3-in Diameter Rockets

These are helpful couplers for joining rocket parts together.  I try to stock parts for scratch-building my rockets and cardboard couplers are much lighter.  However, I am also cheap and since I have the 3D printer, I use it when it makes sense.

I have included three different ones (I may add more), but you can simply load these up into your favorite CAD app and modify them to your needs.

1. Nose Cone Coupler - for use when you have a nose cone without a shoulder.  It also has two ribs to help reduce drag separation
2. Squared - simple cylinder with enough meat to keep the two halves together
3. Beveled - same as the squared with a bevel on either end.

Use:

For the Squared/beveled, you can adhere them to the tube with epoxy or CA.  When permanently two tubes together, mark the center and join the coupler with one tube and let the adhesive set.  Then join the 2nd half.  Once everything is done, you have a very strong joint.

For the nose cone, insert the coupler into the nose cone until it seats.  Adhere with your CA or Epoxy.  The ribs can be sanded to make them smoother or taped over for a tighter fit.

I use these to make longer tubes and to extend existing tubes, making my rockets extendable.  I build out my booster section just longer than my motor tube.  Then with the coupler, join the body tube with the booster and lock them together like you would with plastic rivets but I use threaded inserts with a machine screw.  Three to four screws are plenty.  Here are the links to the hardware I use:

• Threaded inserts
• Machine Screws

Please Note:  These were sized for my specific need.  They might be loose or tight for your usage (aka. Pringles Rocket).  Your mileage may vary.

If you find these useful, please throw me some love by posting a make and let me know how they worked in your project.