Fasteners for CAD Models

[Joedang]

The Problem

Most/all of the CAD for LV3 does not include fasteners, even though we have particular ones in mind.

The solution

• Go through and identify/specify all the fasteners. I'm pretty sure it's just:
  • countersunk screw (hex) for connecting modules (female, male)
  • machine screw (hex) for mounting internals to modules
    Make sure the countersunk and machine screws won't collide when attaching the spider, thrust flange, or cradle lid when mounting them in either hole position! On the male ring, they enter the same hole from opposite ends. On the female ring, you will need to use a fastener that's shorter than the full depth of the hole, because some of the far end will have structural adhesive in it. (see example drawing) Ideally, you might get away with specifying a single length of machine screw and a single length of countersunk screw.
  • optional (plastic) washer for internals (not yet specified)
    This is for parts like the cubesat cradle lid, which have round faces where the fastener clamps down.
  • threaded rod for connecting motor to spider
  • nut for attaching motor to spider
  • threaded rod for attaching nose tip to nose plug
    • 9/16-12 Helicoil
    • Need to specify rod length
• If necessary add callouts to the relevant model/drawing for the fasteners.
• Find/make SolidWorks models for all the fasteners and put them in cad/COTS.
• Put together a bill of materials. (How about cad/BoM.md?) This should include: what the part is called (e.g., 9/16-12 threaded rod), a link to the model of the part, links to the parts/assembles that interface with it, how many go in a rocket, optional link to a site where it can be purchased if it's COTS.
• Add the fasteners to the assemblies.
  Mate countersunk screws as coincident cones and everything else as concentric holes with contacting faces.
• Update the drawings, superassemblies, and PDFs.

It's a VERY good idea to go and physically confirm this stuff with the parts in meatspace whenever possible. Like, go get the part and fastener from the rocket room and confirm that they fit and that they're the size you think they are. (Talk to @Joedang, @7deeptide, or @alexkazam if you need help finding them.) This would include the: male ring, female ring, spider, and thrust flange.

[Joedang]

@RocketmanYG, you said you wanted to make a BoM for LV3. This would be some relevant stuff for that.