markpsmith

markpsmith

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I am working on my RV-8 HS front spar. I am getting ready to rivet the HS-810/814 to the HS-702. The center 4 holes (ones with flush rivets) call for AN426AD4-6. These seem too long.

I think a 4-5 would work fine - problem is that none come with the empenage kit. Should I just order some 4-5s? Or am I missing something here?

http://img330.imageshack.us/img330/5578/10303765nf.jpg

The link above was stolen from another post, but shows the 4 countersunk holes I am talking about (right in the middle of the pic).

Thanks,
Mark
RV-8 Emp
 
Should stick out about .1875". Take it to the SB wheel if its a little too long.
 
Order Rivets

If you're just starting out, go to your favorite hardware supplier (Aircraft Spruce, Wicks, local, whatever) and order a bunch of rivets, in 3 and 4's with some 5's (you won't need many of those). Order about 1/4lb in almost every size; they're cheap.
 
Here is a pic of it

Here is the actual pic.

It sticks out 13/64" (0.203")

1000485mm8.jpg


Mark
 
Cutting Rivets

Being cheap; yet knowing I'd always need a few 'odd length' rivets; I bought some long ones and cut them. As a cutter, I use one of my electrical crimp tools that has threaded holes for cutting machine screws. It does a really nice job, plus I use it to cut screws to length. I don't remember where I got it, I've had it forever; you can pick them up at the Aviation department of Lowes, Radio Shack, etc.
 
The rivet should stick out 1.5 times the rivet shank diameter. For a 4/32 rivet that would be 6/32 so your 13/64 sounds like you have the correct length rivet for the job. Anything else would be too short.
 
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The rule of thumb is for a rivet shank to stick out 1.5D before being squashed. In the case of a 1/8" diameter rivet, that equates to 3/16" -- or 12/64".

If your rivet sticks out 13/64", then it's only off by 1/64". Going with the next size up or next size down rivet, you'll be off by either 3/64" or 5/64". My point is that you'll be even further away from the 1.5D rule of thumb.

If you have a rivet cutter, sure, you could make your own custom perfect rivets.

OR YOU COULD JUST SQUEEZE THAT PUPPY AND CALL IT GOOD.
 
Thanks everyone...

We must all just be sitting at work browsing the web...Such quick responses :)

I guess my issue was with the length the rivet extruded I ended up with 1.5D shop head, although, the height of the shop head was more than 0.5D. Otherwise to make the height 0.5D, I would have to buck it more which would make the diamater more that 1.5D.

I am probably being too anal. I just went with whatever height the 1.5D shop head gave me - which ended up being a height of about 0.8D.

Thanks for the help,
Mark
 
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Sometimes the rivets like to squish over to the side if they are too long. I find that if they are in a bad location, its better to have them the exact length prior to squeezing to lessen the chance of a badly formed rivet. Your experience is a factor as well. Trim it if you want, you will probably end up with a better shop head if you do.
 
markpsmith said:
We must all just be sitting at work browsing the web...Such quick responses :)

I guess my issue was with the length the rivet extruded I ended up with 1.5D shop head, although, the height of the shop head was more than 0.5D. Otherwise to make the height 0.5D, I would have to buck it more which would make the diamater more that 1.5D.

I am probably being too anal. I just went with whatever height the 1.5D shop head gave me - which ended up being a height of about 0.8D.

Thanks for the help,
Mark
Click to expand...
Those dimensions are minimums not maximums. Your rivet gages are no-go gages. The shop head should be at least 1.5 D in diameter and at least .5 D in height.
-mike
 
G-force said:
Not totaly accurate...1.5d and .5 d are good ranges to shoot for, but the Mil Spec. has actualy numbers for the min/max dimentions.
Click to expand...
Amen, Brother. You beat me to it.

Here's some good advice to all new builders. Take your rivet gauges, and toss them into the nearest garbage can, right now! Many thousands of perfectly acceptable rivets have been drilled out over the years, because they didn't fit the rivet gauges. Get yourself a copy of the Mil-spec and a dial calipers, and you'll be in a better position to judge your rivets.
 
I agree that the .5d and 1.5d limits are not absolute minimums. BUT, these are certainly what the amateur-builder should shoot for. Keep your gauges and use them. If a rivet does not meet these specs, then measure that rivet individually. But continue to strive for the .5d and 1.5d limits.
 
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Mark...Just a thought, but I have on a rare occassion, found a misplaced group of rivets...measure the rivet and confirm it is in fact a 4-6???
 
sprucemoose said:
Take your rivet gauges, and toss them into the nearest garbage can, right now!
Click to expand...
Mel's right. This was tongue-in-cheek, but I believe that the rivet gauges, used by themselves, are next to useless. They must be used with the knowledge of the mil-spec and what the true tolerances are. I'm afraid most new builders are ignorant of this, and I certainly was until somebody pointed it out to me. I make a point of demonstrating this on every intiial tech counselor visit, and I haven't found anybody yet who already knew.

The real danger is that a perfectly acceptable rivet gets drilled out, using less than perfect technique, and now you have a buggered hole and a bigger problem than you started with.
 
I used the rivet gauges but I have to admit, back when I was doing my wing skins and bucking and shooting by myself....I used my finger to evaluate whether the shop head (which,if course, I couldn't see since the wing was closed) was any good. Is that crazy? You know, over the years, I've "calibrated" my finger with those rivet gauges and darn if those times when my finger told me the rivet wasn't bucked enough...it usually wasn't.... and when it told me it was, it was.

And the price of this tool was right, too.:D
 
Err to the short side

I agree with the sentiments here. Don't waste too much time with your rivet length gauges. I worked for a while in an aircraft sheet metal shop after finishing my RV-4. I was surprised to see that the pros always used shorter rivet lengths than Van's plans call out, and never used rivet gauges. They just eyeballed the rivet length to "that looks about right" and banged them home. They never checked the shop head either. If it looks like a good rivet, not clenched over or squashed flat, just leave it alone and move on. It is easier to drive an acceptable rivet if the length is a little short than if it's a little long. Since we are usually driving rivets in brand new, clean, properly-sized holes, we will have much more consistently good rivets by erring to the short side than the long side.

When you drill rivets out you will always enlarge the hole, making it harder to drive a good rivet. Not a big deal (most of the work in the sheet metal shop involved drilling out lots of rivets and replacing skins), but there is no need to drill out an otherwise acceptable rivet. If the shop head looks like a rivet, leave it alone!
 
No - slightly longer is usually better

Tweetr said:
.....
Since we are usually driving rivets in brand new, clean, properly-sized holes, we will have much more consistently good rivets by erring to the short side than the long side.

When you drill rivets out you will always enlarge the hole, making it harder to drive a good rivet. Not a big deal (most of the work in the sheet metal shop involved drilling out lots of rivets and replacing skins), but there is no need to drill out an otherwise acceptable rivet. If the shop head looks like a rivet, leave it alone!
Click to expand...

Tweetr (huh?)

We usually don't have the "brand new, clean, properly-sized holes" you mention above when we are driving -3 rivets into two sheets of metal that have both been dimpled. In this case - sort of the usual RV hole - the hole has probably been enlarged by the dimpling process, and certainly does not have straight sides.

Because of these two factors, I have found that often a rivet that is a 1/2 size longer than Vans call out works better, and will still be easy to drive. I believe erring on the short side will give undersize shop heads.

The shop height of a rivet needs to be correctly measured, the Avery rivet gauges can give an incorrect reading. See the sketch on my home page....

http://home.earthlink.net/~gilalex/

Remember the 1.5 protrusion standard is for clean, straight sided holes that are within the Mil-Spec diameters listed on my web site (post #12).

Rivets can be drilled out carefully without harming or enlarging the hole, but it does take some skill and a different technique...

http://www.vansairforce.com/community/showthread.php?t=10533

gil in Tucson
 
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