Shear Pins or Rivets?

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thom9894

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I am building a 4" LOC Nike Zeus. 2nd HPR, and not ready for dual deploy yet. However, I hope to use this rocket to learn eventually. So I bought the LOC EB-390. I'm thinking to build with the standard coupler between booster and sustained and have the ability to swap for the E-bay.

Should I just use qty 3 #2-56 nylon shear pins to attach the coupler to the payload section for motor ejection? I've also read about nylon push rivets. Seems like they are going to take larger holes, but since in either configuration this upper side of the joint isn't supposed to separate it would be a cosmetic difference. Although, if the NC were attached with 3 shear pins like the E-bay, that could be trouble in DD, with the potential to blow the E-bay instead of NC.

Thoughts? Any pictures of installed push rivets out there?

Thanks!
20210224_064033.jpg
 
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Mike Haberer

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Use screws for now. If you are using 3 I don't think it matters if they are metal or plastic (shear) screws. You'll want to put shear pins on your payload/nose cone joint anyway so you don't lose your nose cone when doing SD motor ejection, so as long as you are using shear pins there you might as well use the same ones for the payload/coupler joint. They won't break loose. Place the screws where you would place the rivets. When you get to DD drill the holes bigger for the rivets. Drill both the AV-Bay (first) and then the coupler using the payload section rivet holes as the guide for the coupler. That way you can continue to swap between SD and DD depending on field size and wind conditions.
 

mbeels

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Thoughts? Any pictures of installed push rivets out there?
I find the push rivets easy and convenient. Apogee has photos of them installed on a rocket, they look like thin black disks:

 

teepot

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I use plastic rivets or screws. It depends on how often I want to have access to that part or section. I use shear pins on the nose cone for dual deploy.
 

thom9894

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I use plastic rivets or screws. It depends on how often I want to have access to that part or section. I use shear pins on the nose cone for dual deploy.
plastic rivets like the Apogee ones @mbeels mentioned I assume? And screws - plastic or metal?
You say "shear pins on the nose cone" - Apogee and LOC both sell Nylon Screws as shear pins. Or do you mean something else, like polystyrene rod?
Thanks!
 

DragonRocketry

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I use 4-40 buttonhead screws and t-nuts. See picture below.

IMG_1223.jpg
IMG_1222.jpg
 

teepot

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plastic rivets like the Apogee ones @mbeels mentioned I assume? And screws - plastic or metal?
You say "shear pins on the nose cone" - Apogee and LOC both sell Nylon Screws as shear pins. Or do you mean something else, like polystyrene rod?
Thanks!
Yes, the rivets Apogee sells. Their shear pins too. And metal screws.
 
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