Airframe screws exterior radial mounted?

A trivial question of what screws are people using to join airframe tubing to couplers together in ground removable yet non flight shear able applications? I want to use screws for upper tubing to Wildman nosecone on a Mac hyper 54 to allow ease of access to a thermocouple mount in the nosecone. At least that’s an idea I got floating around right now. I do not want the screws to act as shear pins. Suggestions?

How about reusable plastic rivets?
https://publicmissiles.com/product/hardware

Working on this bigger/thicker fiberglass today. I used floating nut plates. I'll have three 6-32 screws holding this 5.5" payload to the coupler.

I just checked the material thickness it’s 0.149” joining the nosecone tube and Mac airframe tube so the plastic rivets are out. Eric or others where are you sourcing the floating nut plates and 6-32 screws from?

Well mine come from my spares bin at work. But aircraft spruce sells these ones. I'm sure others sell them as well. But floating is nice, as it doesn't have to be perfectly centered when riveted in. My fiberglass thickness is .110" body tube, and .090" coupler. So I have a lot of room for countersinking screws and rivet heads.

But there are different lengths of plastic rivets that I believe will still work for your setup.

Eric said:

But there are different lengths of plastic rivets that I believe will still work for your setup.

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There are. I want to say either McMaster Carr or Grainger sell quite a variety. I bought a bunch many years ago.

For fiberglass I use #2,4, or 6 stainless button head screws and PEM nuts.

Cardboard gets push rivets.

McMaster Carr:
https://www.mcmaster.com/nylon-rivets

There is a product specifically made for this and has chemical treatment on the surface to aid bonding.
Apogee Components sells the LumaDyne fasteners.
https://www.apogeerockets.com/LumaDyne

I generally use M4 countersunk screws for the task. Mostly tapped into fiberglass that has been beefed up in thickness. Sometimes not even countersunk. Depends on the rocket. Occasionally, but usually not, I will make use of swage nuts or some similar method to provide a metal thread to screw into.

Second the PEM nuts. Key for proper install is correct drill size. I normally glue over post insall (belt and suspenders).

Another PEM nut user here. Missileworks sells them in small quantities for a reasonable price in sizes 4-40, 6-32 and 8-32. McMaster-Carr and Fastenal sell them in 2-56 if you need to go smaller.

timbucktoo said:

McMaster Carr:
https://www.mcmaster.com/nylon-rivets

Click to expand...

I like these but look at various options.

I use M4 and 4-40 set (Grubb) screws in fiberglass and CF a lot. It works really well. Just drill and tap the holes.