[RVG8tor]

I need some reassurance. I riveted my main spar double and hinges of the VS yesterday. I used the rivets called for in the plans but they seem to leave a shop head that is slightly taller than what the mil spec calls for. I am wondering if this is because the rivets were longer than they should have been for the thickness of material. If they were too long why would Van's call for this size.

I used a pneumatic squeezer and if I dial in some more to flatten the rivet there is a point where it just did not do any more and sometimes would not even move the next rivet I tried to squeeze, until I dial the set back some. The rivets mostly look nice but just a little tall. The mil spec I have for -4 rivets (1/8) is .05 to .07 min head thickness, mine are .077 to .08. Min diameter .163, all of mine shop head are .190 to .200 so I am OK here.

If you use a taller rivet than required would one expect to get a taller shop head? The way I look at it I have 3 options;

1) Buck the rivets to a smaller shop head height, not sure how this will work now that they have all been set.

2) Drill out the rivets and re-rivet with shorter rivets. Or order new parts and use them, I kind of think I might make a mess out of drilling so many rivet out.

3) Leave well enough alone, I feel like the parts are structurally sound, but I have no experience to base this on.

Thanks for any help.

 

[jmartinez443]

I need some reassurance. I riveted my main spar double and hinges of the VS yesterday. I used the rivets called for in the plans but they seem to leave a shop head that is slightly taller than what the mil spec calls for. I am wondering if this is because the rivets were longer than they should have been for the thickness of material. If they were too long why would Van's call for this size.

I used a pneumatic squeezer and if I dial in some more to flatten the rivet there is a point where it just did not do any more and sometimes would not even move the next rivet I tried to squeeze, until I dial the set back some. The rivets mostly look nice but just a little tall. The mil spec I have for -4 rivets (1/8) is .05 to .07 min head thickness, mine are .077 to .08. Min diameter .163, all of mine shop head are .190 to .200 so I am OK here.

If you use a taller rivet than required would one expect to get a taller shop head? The way I look at it I have 3 options;

1) Buck the rivets to a smaller shop head height, not sure how this will work now that they have all been set.

2) Drill out the rivets and re-rivet with shorter rivets. Or order new parts and use them, I kind of think I might make a mess out of drilling so many rivet out.

3) Leave well enough alone, I feel like the parts are structurally sound, but I have no experience to base this on.

Thanks for any help.

I vote for #3. The shop heads on my VS rivets are slightly taller but exactly the diameter of the rivet gaugue. Build on.

 

[Guy Prevost]

Tall shop heads are not a problem. So are large diameter, so long as they are tall enough. You don't want short shop heads, or shop heads of too small of a diameter. A rivet guage from Avery or Cleaveland is a really nice thing to have. It's a go, no-go guage for minimum height and diameter.

The tall shop heads means that the rivets are slightly longer than necessary. If they are good rivets and not bent over, you are good to go. I'm guessing if they were much longer you would have a hard time setting them properly.

 

[alpinelakespilot2000]

Leave the rivets! There is no problem with using rivets that are too long so long as they set properly. A shop head that is wider than necessary and/or taller than necessary is just fine!

 

[RVG8tor]

Many Thanks

OK just what I wanted to hear, I am not sure why I even let myself read the Mil Spec on max shop head size. I do have the rivet gauges and all of my rivets are well withing the gauges, taller than the notch and bigger than the hole. VS skin next, until next question thanks for the help guys.

Cheers

 

[az_gila]

Not go/no go

Tall shop heads are not a problem. So are large diameter, so long as they are tall enough. You don't want short shop heads, or shop heads of too small of a diameter. A rivet guage from Avery or Cleaveland is a really nice thing to have. It's a go, no-go guage for minimum height and diameter.

The tall shop heads means that the rivets are slightly longer than necessary. If they are good rivets and not bent over, you are good to go. I'm guessing if they were much longer you would have a hard time setting them properly.

Guy... the Avery rivet gauges are not accurate go/no go gauges.

The hole is 1.5 D which defines a "perfect" rivet dimension. The Mil-Spec (which really defines an acceptable rivet) allows a much smaller diameter shop head of about 1.3 D. Table III on my web site (and copied onto many more web sites......) gives the numbers...

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

If you want a true "no go" gauge, just drill a 1/8 (for -3 rivets) and a #19 (for -4 rivets) hole in a scrap piece a aluminum strip - this will be the "no go" minimum shop head size, with about a 0.003 inch safety factor built in (i.e. very slightly conservative)

Use the Avery gauge to aim for optimum, but if it's under, evaluate for size before reworking....

I believe the maximum height dimension is to set a design clearance limit between riveted assemblies, but I haven't been able to verify this...

gil A