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Okay to use one size longer rivet?

T

tdragger1966

Member
Hey folks, new guy here so this is probably a dumb question..

I just bought an almost complete RV-10 tail from another builder and was excited to work on the few remaining tasks. Decided to start by fabricating the trim servo linkage and immediately discovered the hardware that came with the kit had but a single AN470AD4-7 rivet left. I have plenty of 4-8 rivets. Assuming I set the rivet correctly is there any problem using the slightly longer one? Would hate to hit a wall waiting for a single rivet to ship.

Thanks in advance!
 
rivet gauges & rivet cutter

Make sure you've got these tools and use them. The gauge to ensure you've got the rivet right before & after setting, and a cutter comes in handy if you've got a stash of longer rivets and you need to shorten them.

Sometimes (very occasionally) the rivet callouts on the plans aren't quite right and you may need to go for a longer rivet. If they're too long they'll clinch, but if it sets OK then move on.
 
A few thoughts:
- Always use the right size rivet (use your rivet gauge). This may not be what is listed in the plans as many call outs are under size (especially true for 3-3.5 really needing to be 3-4, or 4-4 really needing to be 4-5).
- You can always cut a rivet if it is too long - use a standard rivet cutting tool. Not something you want to do other than once in a blue moon.
- Just order a bunch of rivets from Van’s. A tenth of a pound is cheap and it goes a long way. You will need more anyway for all the “extra stuff” you will end up adding.

After three builds I have bags of 3-3.5 rivets left over as many were replaced with 3-4.

Carl
 
Longer rivet?

You can use any rivet you have on hand and cut it to length. The cut doesn't have to be pretty, when forming the shop end it will all get mashed together and look (and function) just fine. Many shops just have long rivets of each type on hand and cut them with diagonal pliers to suit the task at hand. If you are using a lot of the same length then it becomes more practical to order the appropriate rivet, otherwise just improvise...it's perfectly airworthy and impossible to tell the difference once driven.
Bruce
ATP A&P
RV-7A (purchased)
2020 dues gladly paid!
 
One thing I recommend to new builders is they have a rivet cutting tool and buy a small quantity of LONG rivets in each of the 3 commonly used sizes/shapes used in the RV's. That way you can custom make any length rivet you need.
 
Thanks. I read about rivet cutters in "Aircraft Sheet Metal" but didn't think I'd need one so soon. :eek: I guess the good thing is that (a) this is not a cosmetic piece and (b) it is easily inspected and removable in case I need to drill out/replace.
 
tdragger1966 said:
Thanks. I read about rivet cutters in "Aircraft Sheet Metal" but didn't think I'd need one so soon. :eek: I guess the good thing is that (a) this is not a cosmetic piece and (b) it is easily inspected and removable in case I need to drill out/replace.
Click to expand...


You're on the correct thinking path.

As Van says "you're building an airplane, not a watch".
 
A few thoughts:
- Always use the right size rivet (use your rivet gauge). This may not be what is listed in the plans as many call outs are under size (especially true for 3-3.5 really needing to be 3-4, or 4-4 really needing to be 4-5).
- You can always cut a rivet if it is too long - use a standard rivet cutting tool. Not something you want to do other than once in a blue moon.
- Just order a bunch of rivets from Van’s. A tenth of a pound is cheap and it goes a long way. You will need more anyway for all the “extra stuff” you will end up adding.
Click to expand...

Another good idea is to read through the rivet sizing paragraph of Section 5 in the manual.
It describes the rivet sizing philosophy and points to the Mil Spec document that is the standard used for rivets (sizes, finished shop head diameters and heights, etc.).
The danger in jumping a full size (1/16" longer) is that if the spec'ed rivet was just barely short when using the standard 1.5 D rule of thumb, the next size longer will probably be very difficult to set without it clinching over.
That then leads to a rivet that is much lower in strength than it would have been using the next shorter size. Especially if during the attempt to remove it, the hole gets enlarge.

That is why in some instances it seems the called out rivet is a bit too short. There is also a chance that the plans have a typo, but if the called out rivet will produce a shop head that meets the Mil Spec, it was probably specified on purpose.
 
G-force said:
1.5 D is the maximum, you shouldn't be shooting for the maximum. Shoot for somewhere between maximum (1.5 D) and minimum (1.3 D). If 1.3 D leaves you with sufficent height, stop.
Click to expand...

I was talking about the sizing rule of thumb…
Which is, 1.5 D protruding through the material when the rivet is inserted.
My point was that it is not necessary to use 1.5 D to get a proper Spec’ed shop head.
 
It's worth grabbing a couple pieces of scrap the same thickness as the parts and making a trial joint riveting those together. While cutting the rivet to the correct length is best, this might clarify the issues. Also, after you've cut your first rivet, rivet it in the scrap. That will assure you that you did it correctly.

If you have a 10x magnifying glass, examine the rivet and look for cracks.

Dave
 
rivets

All I can add if you do not own a rivet cutter you should, cause they don't cost that much and you really ought to have one. And as soon as you buy it you won't need to cut another rivet of course.
Art
 
If you can squeeze the rivet without bending it, you're fine. Just squeeze it until it has the correct diameter. That said, I shortened some rivets a few weeks ago by just grinding them down on my belt sander. Just a couple of seconds for each one.
 
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