ron sterba

Well Known Member
I was trying to compare strength of (pull style rivet) Cherry Max Q rivets BS Series 5/32 Grade 19 to AN 470-5-2 2117T . the Q rivets have a Shear 525 lbs and Tension 450 lbs. 470 rivets at 30,000 PSI in Shear and 100,000 PSI in Tension. (these #'s I found in the Aircraft Spruce catalog.). Wanted to know the formula to compare PSI to LBS.
Had to remove AN470-4- rivets and the hole was slightly larger so I went to the Q rivets 5/32. I looked in the 43.13 book and did not find a comparison chart between the two types of rivets. Now that the plane is built I could not get into that space with the gun and bar. I am not saying it did not exist in the 43.13 book, I just had enough reading for one night!

It would nice to have a replacement/comparison chart solid to Pull styles.

Thanks Guys,
Ron in Oregon RV9A
 
A -5 rivet is 5/32 = 0.015625. So pi r squared is 3.1415 * 0.015625 ^2 = 0.00076699 square inches. So that times 30,000 for shear gives 23 pounds. 76.7 tension. Unless I messed up the math, the cherry max is much stronger. Probably due to a steel anvil, instead of aluminum.

That said, that number seems small. Somebody check my logic and math?
 
A -5 rivet is 5/32 = 0.015625. So pi r squared is 3.1415 * 0.015625 ^2 = 0.00076699 square inches. So that times 30,000 for shear gives 23 pounds. 76.7 tension. Unless I messed up the math, the cherry max is much stronger. Probably due to a steel anvil, instead of aluminum.

That said, that number seems small. Somebody check my logic and math?

5/32 = 0.15625", the radius is half of that, R= 0.078125"
So the answer is 25 times larger ( 10 squared is 100, but 1/2 squared is 1/4).
More like 25 x 23 = 575 lbs.

PS. ACS says AD rivets are 26000 psi and 38000 psi in shear and tension, respectively. So closer to 500 lbs in shear.
 
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5/32 = 0.15625", the radius is half of that, R= 0.078125"
So the answer is 25 times larger ( 10 squared is 100, but 1/2 squared is 1/4).
More like 25 x 23 = 575 lbs.

PS. ACS says AD rivets are 26000 psi and 38000 psi in shear and tension, respectively. So closer to 500 lbs in shear.

If the original rivet called out was a 1/8" solid "AD" material rivet, then its shear capability would be 319 lbs. That's what the joint was designed for.

If you're replacing that with a 5/32" diameter CherryMax rivet because the hole is now larger, you have improved the fastener shear capability.

However, that is not the only way a joint can fail. If the fastener is near the edge of the material, and the hole is now larger, you have decreased the edge margin (distance from the center of the hole to the edge of the part, divided by the hole radius). This may have moved from a fastener-shear-critical joint to a material-shear-out-critical joint. That's not necessarily bad, it just tells means that something besides the fastener itself will fail first.

A decent visualization:
http://valuablemechanisms.files.wordpress.com/2010/04/types-of-rivet-and-plate-failure.jpg
 
Thanks Gentleman!!

Its good to see that the fastener capabilities has increased in value, thats a good thing. Good point you brought up Kurt about being a shear point close to a edge. In my case I removed the right sub panel in my RV9A slider. I had installed the map box by Vans but found myself relocating my breakers to the right side of the panel to make room for my Dynon Auto pilot modules. (sub panel had the BIG hole) (two skyviews) Looking at the location on the 470 - rivets ( on the vertical and near top and at the longeron at the subpanel) I would be safe to say it should be a SAFE install with the Cherry Max rivets. I'll pull the plans pages and parts #'s when I get to the hangar today.

If there was a company that wanted its brand name out there this would be a GREAT place to put it on a CHART showing the standard AN rivets used in the RV series to that of the CHERRY MAX rivets. Those type charts I have hanging in my hangar. Very helpful!!!!

Ron in Oregon
RV9A
 
Ron,

If you want to really know the strength of riveted joints google "MIL-HDBK-5J" and download a PDF copy of this. It is not the current issue, but the latest you won't have to pay for. I use it as a fundamental reference. No builder should be without this document, unless you want to take someone else's information for all your decisions.

edit: the table you want is on page 1245/1731.

Sorry, I don't have a link but the google search yields the purdue link at the top.
 
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Thanks Bill!..WOW!
Now I'm getting some where. Looks like page 1245 (8-13),1246(8-14),1251(8-19), and cover page #1 is spot on and then in pages 1259 (8-59)are into blind rivets. The Cherry Max rivets I ordered from Air Craft Spruce are listed as CR-3213.
Pretty impressive LBS #s in strength for the Blind protruding head rivets. I believe I have covered the rivets used in my RV9A and the blind rivets in these pages. I 'm open to any additional comments if you have them. Would like to see Vans have a chart in their rivets section as to comparisons. After all little dings DO happen.

Thanks to Vans engineering shaft to have followed the guidelines in Appendix A,B,C,D. !!!!!!!!!!!!

Bill, you are right that every builder should have these charts while building!!!!

If you are a chapter member copy these pages and hand them out to your members!!!

Just a thought.

Thanks again,
Always appreciate the help!

Ron in Oregon
RV9A.
 
Charts ( comparison )Driven to Blind rivets,Shear,LBS

Thanks Bill!..WOW!
Now I'm getting some where. ( MIL-HDBK-5J ) Looks like page 1245 (8-13),1246(8-14),1251(8-19), and cover page #1 is spot on and then in pages 1259 (8-59)are into blind rivets. The Cherry Max rivets I ordered from Air Craft Spruce are listed as CR-3213.
Pretty impressive LBS #s in strength for the Blind protruding head rivets. I believe I have covered the rivets used in my RV9A and the blind rivets in these pages. I 'm open to any additional comments if you have them. Would like to see Vans have a chart in their rivets section as to comparisons. After all little dings DO happen.

Thanks to Vans engineering shaft to have followed the guidelines in Appendix A,B,C,D. !!!!!!!!!!!!

Bill, you are right that every builder should have these charts while building!!!!

If you are a chapter member copy these pages and hand them out to your members!!!

Just a thought.

Thanks again,
Always appreciate the help!

Ron in Oregon
RV9A.
 
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