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Equivalent Cherry rivet

M

MekMouse

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Since the Mothership is seemingly unwilling to commit to a recommendation....

Which Cherry rivet would be the equivalent to an AN470AD4-4? Especially in terms of grip length.

Background: I'm taking care of the last LCP replacement task for my -10 elevators. Which is replacing the tip rib assemblies. Since the trailing edge is riveted and bonded going through the original process is non-viable. Which leaves figuring out a suitable pulled rivet solution. and with the counter weight on the end of this assy there is a structural sheer consideration guiding towards a Cherry rivet.
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So that is dependant on the thickness stack of your parts. Solid rivets have more tolerance there so you should measure and check the chart. There is a chart on the cherry max website which gives grip limits for each dash number. Just look for the universal head /nominal diameter chart. That would be a CR3213. Note that they are more sensative on hole diameter as well. The nominal -4 cherrys have a hole tolerance of .129-.132 if your hole is larger you may need the CR3243 which gives a hole tolerance of .143-.146.

Just look at the grip length side of the chart and follow it over to the length.

Or you can order the grip length gauge and just use that
 
Thanks for the suggestion there, I'll have to get one of those gauges for next time.

I'll definitely measure my stack up once I get home this evening. I think it's 0.070" - 0.080" but actual measurement required
 
Just a note on Cherry max rivets although they have good shear and tension strength comparable to solid rivets if properly installed they have less fatigue strength. So in the couple of places, I have used them I have that listed as a place to have a focused inspection as part of my annual inspection and it will be in the manual i write.
 
CaptPausert said:
Just a note on Cherry max rivets although they have good shear and tension strength comparable to solid rivets if properly installed they have less fatigue strength. So in the couple of places, I have used them I have that listed as a place to have a focused inspection as part of my annual inspection and it will be in the manual i write.
Click to expand...
I read your byline and want to trust you.
Having said that, can you offer source material that supports this claim?
I can only find data comparing some of them to huck clinch rivets
 
RNB said:
I read your byline and want to trust you.
Having said that, can you offer source material that supports this claim?
I can only find data comparing some of them to huck clinch rivets
Click to expand...
So the main source I have for this is a Boeing study not sure if it is publicly releasable (Boeing likes to put proprietary on everything) I will check tomorrow at work and see if I can copy anything from it. Note they Aren't necessary horrible in fatigue just not as good as solid rivets. It is also heavily dependent on the loading on the joint.

It mainly has to do with the fact that blind rivets including cherry max rivets don't expand as much as a solid rivet and fill the hole as well which effects the stress path in the part. interference fit fasteners are the best for this.
 
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After measuring the stackup it looks like the correct size would be the CR3213-4-2. which is very much unobtanium or quite pricey where available.
 
So i orderd some of that size from aircraft spruce in Feburary they were backordered and they shipped in April. About 7 weeks to get them. Not sure how soon you need them
 
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