Rivets too long for rear spar?

[jazzbazzfazz]

I did the preliminary assembly of my rear spar yesterday and found that consistently the rivet sizes called for in the plans were 1 size too long (rivets being squeezed had a tendency to squoosh and topple a little sideways, etc.)

This was for attaching doubler plates to the middle and outboard portion of the spars, and "tripler-plates" to the inboard portions.

Using the next shorter length gave me beautiful rivet heads, though right at the limit of acceptable size. As you may remember, there are still numerous rivets to be set in assembly with ribs, brackets, etc. that will add to the strength of the join.

The questions are:

(1) Has anyone else encountered this?
(2) Am I better off with rivets just at the specs, or longer rivets that appear oversqueezed?

Thanks!

John Walter
RV-9A wings

 

[az_gila]

In spec. is OK

(2) Am I better off with rivets just at the specs, or longer rivets that appear oversqueezed?

Thanks!

John Walter
RV-9A wings

John,

If they are within spec. - by definition they are OK. If they are easier to install that way, then go with the shorter ones.

I presume you are using the dimensions from here as a reference....

http://home.earthlink.net/~gilalex/rivet_spec/rivet_a.htm

....or one of the sites that "borrowed" this data capture.

gil in Tucson

 

[jazzbazzfazz]

I've seen the specs, but use those little anodized rivet gauges as my yardsticks...

 

[cytoxin]

if it fits you musta quits

the gague is the rule though some under or over is ok.(small amounts)
i am a little concerned because vans ususally call to short when they are off. did you prime or not? anywhoo as long as the shop head is good and correct your good to go. use the rivet gague to select correct length

 

[alpinelakespilot2000]

I waited until the fuselage to buy a $15.00 rivet cutter. I wish I would have done it right at the start. Using one provides the opportunity to use half-size rivets. Good luck.

 

[az_gila]

Make your own guide....

I've seen the specs, but use those little anodized rivet gauges as my yardsticks...

John... the guage is probably set up for a perfect 1.5 D "squished" diameter.

For a -4 rivet it is 0.1875 inches

If you check out the spec., it gives the absolute minimum diameter as 0.163 inches

This is about 15% less.... So aim for the "perfect" 1.5 D diameter, but just be aware that you can be 15% undersize and still have a good, strong rivet.

Just for kicks, you could drill a clean #20 hole in a scrap of alum. (0.161) and use this as a definite "no-go" guage. The size of this hole will also give you a good visual guide as to what the minimum acceptable size is.

Remember though, if you drive too much to obtain that perfect 1.5 D diameter, you may be violating the minimum height dimension.... 0.5 D for perfect (0.063), but an absolute minimum of 0.050 inches. Again, this can be compared visually to a piece of 0.050 scrap stock.

If you have good eyesight, it's easy to make up these two references, and then just visually compare. Since we only really use 2 rivet sizes in our RVs, this is easy to do....

Those little anodized thingies just give a center point for driven rivets.....

gil in Tucson ... just use the specs as limits....

 

[N722SH]

John,

I just did this and noticed the exact same thing as you on the middle and outboard doublers. I used the next shorter length and they can out just at the short limit of the rivet gage, but OK.

Scott Harding
-9 deburing wing ribs

PS - I'm now going to buy a rivet cutter so I can get half lengths!