AV Bay Shim Stock for Shear Plates on Both Surfaces?

[PBic]

Hi, I’m finishing up a cardboard 4” Mad Cow Frenzy DD, and am planning on embedding .005” brass shims in the booster tube as I’ve learned here (Thanks all!) What I’m not clear on is whether I need shear shims at the corresponding points of the cardboard AV bay. My thought is that it would be a better scissor action between 2 shims rather than a shim on the booster tube alone. Any input would be greatly appreciated.

Thanks,

Paul B.

 

[markjos]

If you’ve got the patience to put in two at each location, then go for it. But that can be tricky to do. If you harden the holes in both parts (drill undersized, wick in CA glue, redrill), and have shim stock in one, I think you’ll be in pretty good shape. Ground test and see whether holes are deforming, or the shear pins are bending/dragging and not cutting. I hope I’m not pointing out the obvious.

 

[jd2cylman]

I do brass on both surfaces. A PITA, but for the best shear results, it needs to be done. I also do the plastic nose cone shoulders as well...

 

[PBic]

Thanks Mark & JD. I’ll give a go at doing both surfaces. With launch schedules such as they are, I think I’ll have plenty of time.

 

[jd2cylman]

Here's another thing I do. I drill the holes first in the body tube/coupler/nosecone shoulder, then cut out the area for the shear plate. Then put everything together and drill through the brass.