What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Squeezed rivet questions

AndyRV7

Well Known Member
I built the Vans axle wrench this weekend finally. I figured it would be a nice simple intro to the riveting process for me. I am presuming the rivets supplied with the wrench were too short for the project but that seems odd. At any rate, the rivets were 1/8" x 3/8". I used my rivet gauge to check the heads afterward and I could get the head to slide under the depth part of the gauge but the head seemed barely larger in diameter than the 1/8" it began at. It certainly did not fill the circle portion of the gauge. Did I do something incorrect here or are the supplied rivets simply too short?

Thanks!

rivet3_zps7kxtbvv2.jpg


rivet1_zpsx3u4zrlm.jpg


rivet2_zpsxkummvus.jpg
 
?..... Did I do something incorrect here or are the supplied rivets simply too short?

Nope. You did good, but I actually squeezed them harder to make it less bumpy when I wrap my hand on the handle. It's a wrench. It's ok. Squeeze them harder if you want. Good observation.
 
Nope. You did good, but I actually squeezed them harder to make it less bumpy when I wrap my hand on the handle. It's a wrench. It's ok. Squeeze them harder if you want. Good observation.

I double flushed them then wrapped the handle with electrical tape for the same reason.
 
Thanks! I feel better. I didn't think it would cause my wrench to fall out of the sky ;), but I wanted to get some experience with the process so I can rivet the pitch servo bracket in my plane at some point this fall.

Andy
 
I double flushed them then wrapped the handle with electrical tape for the same reason.

Are the rivets supplied AN426 (flush)?

I think the intent is to countersink both sides so that the rivet is double flush. That would make the supplied rivets the proper length.
 
Are the rivets supplied AN426 (flush)?

I think the intent is to countersink both sides so that the rivet is double flush. That would make the supplied rivets the proper length.

Mine weren't. They were universal heads. And too short, just like the OP observed. But the wrench works great!
 
Are the rivets supplied AN426 (flush)?

I think the intent is to countersink both sides so that the rivet is double flush. That would make the supplied rivets the proper length.


No, mine weren't - in the name of experimental aviation, I made the substitution :)
 
I think they were AN470AD4-6 from memory. I saw someone else alternate the direction of the rivets so I did the same. Gave it a creative touch.:D
 
Out of curiousity, how would you get the second flush fit? I presume the first is from a countersunk (shaped) head.
 
As I recall, those avery gauges, the hole is 1.5x the rivet diameter which is considered max diameter. Mil spec is I think 1.3x So I usually try and shoot for between 1.3x and 1.5x The height gauge on the end is the minimum height so if that were a critical rivet, it would be too short. Don't use the rivet call out as a hard fact, use what you need to make a proper shop head. Sometimes this means buying longer rivets and cutting to an odd length.
 
As I recall, those avery gauges, the hole is 1.5x the rivet diameter which is considered max diameter. Mil spec is I think 1.3x So I usually try and shoot for between 1.3x and 1.5x The height gauge on the end is the minimum height so if that were a critical rivet, it would be too short. Don't use the rivet call out as a hard fact, use what you need to make a proper shop head. Sometimes this means buying longer rivets and cutting to an odd length.

Good to know. Thanks. I purchased a boat load of different rivet shapes and sizes from Van's. I even doubled the order because I wasn't sure if I would need soft or hard rivets. I figured I would get plenty of practice with them.

Does anyone know the thickness of the bulkhead rib that I am going to have to mount the servo bracket to? I might like to order some scrap aluminum to make sure I have the correct rivet length before I try to attach the bracket. Thanks!
 
Out of curiousity, how would you get the second flush fit? I presume the first is from a countersunk (shaped) head.

Both sides of the hole are countersunk, then squeezed/bucked with a flush rivet set. The shop head deforms to fill the countersunk area and while it doesn't look quite as neat as the manufactured head side, it does essentially lay flush with the suface of the material.
 
As I recall, those avery gauges, the hole is 1.5x the rivet diameter which is considered max diameter. Mil spec is I think 1.3x So I usually try and shoot for between 1.3x and 1.5x The height gauge on the end is the minimum height so if that were a critical rivet, it would be too short. Don't use the rivet call out as a hard fact, use what you need to make a proper shop head. Sometimes this means buying longer rivets and cutting to an odd length.

Actually the Avery rivet head gauges are checking for meeting the general mechanics rule of thumb of 1.5D wide X .5D high. They are not the Mil Spec maximums or minimum values.
Example: The minimum shop head height of a -4 (1/8" or .125 diam) rivet is .050. that is way shorter than the .5D rule of thumb dimension which is .0625

I agree that specified rivet lengths should always be cross checked but keep in mind that the specified rivets will sometimes seems short when using the general rule of thumb, but will still result in a shop head that meets the Mil Spec dimensions. This is explained in Sect 5 of the construction manual.
 
Last edited:
As I recall, those avery gauges, the hole is 1.5x the rivet diameter which is considered max diameter. Mil spec is I think 1.3x So I usually try and shoot for between 1.3x and 1.5x The height gauge on the end is the minimum height so if that were a critical rivet, it would be too short. Don't use the rivet call out as a hard fact, use what you need to make a proper shop head. Sometimes this means buying longer rivets and cutting to an odd length.

100% correct here

My first VS i built, i used the call out. It was the first thing i ever tried to rivet and did not know any better. The rivets were excessively long. Getting the rivet down to the maximum height made the diameter so large that upon closer inspection with a magnifying glass you could see the rivets had actually cracked
Later on i learned from a friend in boulder who is building an RV3 and has a wonderful build thread in the build area of VAF that they were to long. We cut them down and presto. We were able to obtain the correct finished result.
I think most of the rivet call is good to use as a guide but some of it is flat out wrong.

IMG_2491_zpsqgmetksu.jpg
 
Rivets the point

Andy
Great work. I think you see the point of this whole thread. Don't merely trust that the kit has provided or even called out the right rivet size. Check them. There will be plenty of places in the plans/drawings you will see that calls for your judgement on length.

Have Fun
 
I make it a point to check this forum the night before I work on my plane to see if there is any "extra " knowledge available to help me through a project.
As to the point of this thread, I think that should have been a longer rivet.
Also the wrench handle will look a lot better if you draw file the edges of the metal to get the tool marks out.
As far as double flushing rivets, this will come up on the trailing edge of the rudder.
 
Wow. I'm glad I asked. I have learned more than I even suspected I needed to. Thanks for all the advice!
 
I stand corrected, been years since I drove a rivet. So I pulled out my "Standard Aircraft Handbook for mechanics and Technicians", a book every RV builder should have, and looked it up. Using the 4 rivet for example, it list a minimum and max upset height of 3/64 (.046") and 5/64" (.078"). In precentages thats rounded to .3D to .6D.
Diameter limits are 11/64" (.172") to 7/32" (.218") or 1.3D to 1.7D.
So it does appear the Avery gauges are set to fall in the middle of the acceptable range.

Some other info from the mother ship: http://www.vansaircraft.com/public/Specs.htm


Actually the Avery rivet head gauges are checking for meeting the general mechanics rule of thumb of 1.5D wide X .5D high. They are not the Mil Spec maximums or minimum values.
Example: The minimum shop head height of a -4 (1/8" or .125 diam) rivet is .050. that is way shorter than the .5D rule of thumb dimension which is .0625

I agree that specified rivet lengths should always be cross checked but keep in mind that the specified rivets will sometimes seems short when using the general rule of thumb, but will still result in a shop head that meets the Mil Spec dimensions. This is explained in Sect 5 of the construction manual.
 
Last edited:
I think there's way too much overthinking going on with these rivet gauges and all. If you're doing a slow build, you're going to pound something like 14,000 rivets. Are you going to put a micrometer on every one, drill out the ones that miss the spec by .001", or what?

I used the rivet gauges on the entire build, to give each rivet a quick check...rivet won't go through hole? Check. Rivet won't pass under slot? Check. Next. I could do a whole row of rivets in less time than it took to write this.

If it would do either, then take a look...is it smashed too flat? If only a little, and the diameter is > the hole, probably best to leave it. If it's smashed to **** and gone, probably best to drill it out and do it again. Same for the hole...if it's sloppy in the hole, then it's probably not driven enough. I'm after a "snug" fit, where it just barely won't go. But if it's much bigger than the size of the hole, just *go look at it*. Is it severely over-driven, or is it acceptable.

Are there a few less-than-perfect rivets on my plane? Sure. But there are probably fewer boogered-up holes and oversized rivets from making a marginal rivet situation worse by drilling it out. Haven't fallen out of the sky yet, though.

You're going to drive a lot of rivets. If you get obsessive over thousandths of an inch on every one, you're going to be building for a loooong time. :)

Just my two cents. Take it for what it's worth.
 
I think there's way too much overthinking going on with these rivet gauges and all. If you're doing a slow build, you're going to pound something like 14,000 rivets. Are you going to put a micrometer on every one, drill out the ones that miss the spec by .001", or what?

I used the rivet gauges on the entire build, to give each rivet a quick check...rivet won't go through hole? Check. Rivet won't pass under slot? Check. Next. I could do a whole row of rivets in less time than it took to write this.

If it would do either, then take a look...is it smashed too flat? If only a little, and the diameter is > the hole, probably best to leave it. If it's smashed to **** and gone, probably best to drill it out and do it again. Same for the hole...if it's sloppy in the hole, then it's probably not driven enough. I'm after a "snug" fit, where it just barely won't go. But if it's much bigger than the size of the hole, just *go look at it*. Is it severely over-driven, or is it acceptable.

Are there a few less-than-perfect rivets on my plane? Sure. But there are probably fewer boogered-up holes and oversized rivets from making a marginal rivet situation worse by drilling it out. Haven't fallen out of the sky yet, though.

You're going to drive a lot of rivets. If you get obsessive over thousandths of an inch on every one, you're going to be building for a loooong time. :)

Just my two cents. Take it for what it's worth.

I largely agree with you but only to a point......

If someone holds them self to always meeting the rule of thumb guide line (the check when using the rivet gauges), then they will at times be using rivets that are more difficult to set consistently. This happens when the ideal rivet length would be a .5 size when they do not exist. Sure you could spend a lot of time cutting a custom length but that makes no sense. So you can use the slightly longer length which will meet the shop head size requirements of your rivet gauge, but risk them leaning over because the rivet is just slightly too long. Or you could use the length that seems slightly too short, but will still produce a shop head that meets the mils spec for dimension minimums but will not meet the rule of thumb dimensions as checked by the rivet gauge.
A lot of the rivet length call outs in the plans that people think are too short, were made based on this standard. Particularly in difficult to rivet areas where it would also be difficult to remove a rivet if it got messed up during installation.

Best practice (once you learn to judge shop head sizes) is to use a rivet that reliable and repeatedly meets the shop head dimension minimums. The rivet gauges are not checking for the minimums.
 
Actually it is not.
See post # 13

When i said i 100% agree i was just referring to the fact that the rivet call out is not correct. Not referring to the avery rivet gauges. I should of clarified.

My photo above is proof that the call out is often wrong and results in adding things to your scrap pile. Im not to worried about the call out being short sometimes. As long as it meets the requirements. What i do not like is when the call out is LONG. Which i have found on the vertical stab and other locations.

As i said in my original post and with the picture. Using the call out and trying to get it to the max height results in cracking when the call out is to long. Its diameter increases so large that as you even get near the max height it cracks as demonstrated in the photo. Short call out i don't see a problem with. Long will become a problem
 
Back
Top