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-   -   Elevator Hinge Bearing Rivets Too Short? (https://vansairforce.net/community/showthread.php?t=163172)

tswanson 08-13-2018 06:18 PM

Elevator Hinge Bearing Rivets Too Short?
 
I'm assembling the HS-411APP, VA-146, and HS-411BPP (the main center bearing and bracket assembly) and Vans calls out an AN470AD4-5 rivet. This rivet only protrudes .106 before squeezing and only about 0.035" after squeezing to form the desired 0.1875" diameter shop head. This seems quite a bit too short to me.

I've read several places that rivet lengths are just guidelines etc, but I don't see anything about this spot specifically. Has this been everyone else's experience with this hinge assembly as well? Is this like this for a reason? I could easily squeeze -6's in there without bending them over. Just making sure I'm not missing something. Kindof an important one...





Thanks,

G-force 08-13-2018 08:29 PM

Standard Aircraft Handbook (every RV builder should own this book) calls for a 1/8" rivet to start with a protrusion of 1.5 times the diameter (0.187) and a shop head heigth of .046" to .078" with a diameter of .172" to .218." Hanson Rivets has a slightly different range on their webpage listed at https://www.hansonrivet.com/rivets/s...-solid-rivets/ That said, I would use the 4-6 rivets.

terrye 08-13-2018 09:10 PM

Elevator Hinge Bearing Rivets Too Short?
 
My RV-9A drawing 3 rev R1 calls out an AN470AD-6 rivet here. Look closely on the plans, sometimes a '6' looks like a '5' if the print process is not absolutely clear.

You should have a rivet gauge that shows 1.5x the rivet diameter on the undriven shank, if not a ruler graduated in 1/32" can be used to verify the correct length.

It may be just the scale of the pictures you posted, but the rivet shop head looks over driven to me. Table III MIL-R-47196A shows a driven head minimum diameter of 0.163" and a driven height of 0.050-0.070". I think you can download this standard from Vans or www.everyspec.com

tswanson 08-13-2018 10:20 PM

Thanks guys. That's what I figured but thought I would double check. Looks a lot better with the 6's.

Thanks guys. I like it a lot better now.

Warbo 08-14-2018 12:49 AM

G?day Todd,
Have a look in Section 5 General Information in your preview plans where it talks about riveting. You will find this note:
NOTE: There are times when the correct rivet length is not available. Depending on the application a shorter rivet can be used or a longer rivet cut to the proper length. Using a longer rivet, as is, can result in the shank being bent over like a nail. We have chosen to use a rivet that may seem too short in some places, but will do the job adequately.
I?m pretty sure this is one of those occasions where Van?s have chosen a shorter rivet that will do the job adequately.
Cheers

az_gila 08-14-2018 09:36 AM

Thicknesses
 
Quote:

Originally Posted by Warbo (Post 1280621)
G’day Todd,
Have a look in Section 5 General Information in your preview plans where it talks about riveting. You will find this note:
NOTE: There are times when the correct rivet length is not available. Depending on the application a shorter rivet can be used or a longer rivet cut to the proper length. Using a longer rivet, as is, can result in the shank being bent over like a nail. We have chosen to use a rivet that may seem too short in some places, but will do the job adequately.
I’m pretty sure this is one of those occasions where Van’s have chosen a shorter rivet that will do the job adequately.
Cheers

I would disagree. :)

If you add up the thicknesses involved - two x 0.050 and 0.063 - then calculation would give a theoretical 5.5 rivet length. The protrusion of a -5 rivet would only be 1.25X rather than the usual 1.5X.

That would be acceptable but - add to that stack-up 4 layers of usually quite thick Vans powder coating and 2 layers of whatever primer you are using and the 1.25X exposure number rapidly decreases. :)

A -6 rivet would be appropriate.

rvbuilder2002 08-14-2018 10:53 AM

Depends on the standard that you use.......


The .5D / 1.5D rule of thumb is a guidance published in AC43 and other mechanic reference documentation.

The absolute standard (in the eyes of the engineering dept at Van?s anyway) is the Mil spec (available on Van?s web site and referenced in Section 5 of the construction manual)

In the first photos where the -5 rivet was used, it is clear that the rivet was over squeezed (probably in an attempt to meet the 1.5D rule while using a rivet gauge). If the Mil Spec dimensions were used as a reference instead, and the rivet wan?t over squeezed, the -5 probably would have been totally acceptable..

az_gila 08-14-2018 11:07 AM

Quote:

Originally Posted by rvbuilder2002 (Post 1280733)
Depends on the standard that you use.......


The .5D / 1.5D rule of thumb is a guidance published in AC43 and other mechanic reference documentation.

The absolute standard (in the eyes of the engineering dept at Van’s anyway) is the Mil spec (available on Van’s web site and referenced in Section 5 of the construction manual)

In the first photos where the -5 rivet was used, it is clear that the rivet was over squeezed (probably in an attempt to meet the 1.5D rule while using a rivet gauge). If the Mil Spec dimensions were used as a reference instead, and the rivet wan’t over squeezed, the -5 probably would have been totally acceptable..

I agree, but why make it harder on the builder to carefully control the amount of setting to precisely meet the Mil-spec standard at it's minimum level?
When the option is to simply use a -6 length rivet to give the builder much more tolerance in his/her riveting.

What is Vans thickness tolerance on the powder coating since 4 layers come into the equation?

rvbuilder2002 08-14-2018 05:37 PM

Quote:

Originally Posted by az_gila (Post 1280737)
I agree, but why make it harder on the builder to carefully control the amount of setting to precisely meet the Mil-spec standard at it's minimum level?
When the option is to simply use a -6 length rivet to give the builder much more tolerance in his/her riveting.

What is Vans thickness tolerance on the powder coating since 4 layers come into the equation?

When the day comes that you have spent 100's of hours doing builder tech support that includes selling frustrated builders new parts to replace the ones they messed up while drilling out clinched over rivets ( which occurred because they are a rank beginner, the hinge bearing is one of the first parts they build, and a -6 rivet is at the long end of the season tolerance range which makes them very prone to clinching over if the setting process is not done perfectly) that everyone on VAF said they should remove. (How is that for a run on sentence?) Then I might concede to your suggestion.


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