[llavalle]

I started building the elevators and was wondering something...

The plan show the skin to spar rivets to be AN426AD3-3.5 on top and CS4-4 on botton. I get it, one side uses regular rivets, the other one, blind rivets.

The manual state that you can, if you want, use AS426AD3-3.5 on the bottom size, where a squeezer can reach (using the holes in the leading edge to get to them)

Here's the catch : 426AD3 rivets require a #40 hole + #40 dimple. CS4 rivets require a #30 hole + #30 dimple.

The hole, I can oversize... but not the dimple...

I realized that when I closed up my rudder : on the lower section, 1 of the 4 rivets that join the skin to the rib to the horn was unreachable with my sqeezer. I could not get a buck bar in there. The plan said "CS4-4 optionnal". I oversized the hole and without thinking about the dimple, I installed a CS4 rivet in there. The head is sticking out a bit (not too much).

I can live with that, it's on the lower section of the rudder and it's only 1 rivet on each side... but I don't want to repeat this error on 1-2 rivets around the holes in the elevators.

I also read somewhere that CS4-4 rivets are countersunk to 120deg, not 100deg like the other ones. Should I buy a 100deg countersink bit + dimple?

What would you do?

 

[Tkitchen1]

Why cant you dimple to #30? I had no issues. as for getting the existing rivet flush, I use a dremel with a rubberized ultra fine wheel on it. It is easy to control.

 

[allbee]

or you can just counter sink a smidge to get it flush after dimpling, worked for me.

 

[JHines]

Why cant you dimple to #30? I had no issues. as for getting the existing rivet flush, I use a dremel with a rubberized ultra fine wheel on it. It is easy to control.

I'm guessing because he dimpled the whole line of rivets (and the underlying rib flange) in the photo to #40, and didn't realize the necessity of the larger dimple until all but that one rivet had been set. Been there, done that.

Subsequently I bought a 120 degree dimple die and countersink. Cleaveland and Avery both sell dimple dies and countersinks specifically for CS4 rivets. Kind of frustrating, at first, that they are not listed as needed items, either by the tool supplier or Van's.

I can only repeat Bill Repucci's advice, when you get to a point like this, stop, suck it up, buy the special tool.

 

[llavalle]

I'm guessing because he dimpled the whole line of rivets (and the underlying rib flange) in the photo to #40, and didn't realize the necessity of the larger dimple until all but that one rivet had been set. Been there, done that.

Exactly. This was the last rivet. The skin + rib + attach strip were already dimpled to #40 and riveted...

albee : What do you mean by "a smidge"? If I get into the same situation again, I oversize the hole to #30 then counter sink a bit? is that right?

I'll try this out on a scrap piece... if it does not turn out the way I want, I think I'll just buy the 120deg C/S cutter and dimple die.

thanks.

 

[alpinelakespilot2000]

If I get into the same situation again, I oversize the hole to #30 then counter sink a bit? is that right?
QUOTE]
I would be careful about doing this on a whole line of rivets, although it might be your only option. Good idea probably to check with Van's. This part definitely took a lot of preplanning for me because I used a combination of AD3 and CS4 rivets. It is really easy to get yourself painted into a corner.

 

[RyanM]

Disclaimer: I'm building a 7.

What about using an MK-319-BS rivet in places like this? It fits into a #40 dimple, but the hole needs to be opened up a tiny bit to 7/64. If the pieces are too thick for the grip range of the 319's then this won't work.

 

[Mel]

Yep,

As long as it is within the grip range, an MK-319BS will work just fine. But not after the hole has been opened up to #30.

 

[allbee]

Exactly. This was the last rivet. The skin + rib + attach strip were already dimpled to #40 and riveted...

albee : What do you mean by "a smidge"? If I get into the same situation again, I oversize the hole to #30 then counter sink a bit? is that right?

I'll try this out on a scrap piece... if it does not turn out the way I want, I think I'll just buy the 120deg C/S cutter and dimple die.

thanks.

Yup that's right, you drill out a little bigger grab the debur tool, that's what I used, than cut a little until the pull rivet sets in there the way you like it and you're done. Done that type of thing through out the airplane. If I used the counter sink tool I took it out of the tool and put it right on the drill and then cut it.

 

[allbee]

Oh, one more thing, I like also the BS revit. But when you have troubles with the fit, like on the canopy with the strut. They have you dimple for the screws, it looks awful, the screws stuck out a little, so I hit it with a cutter to bring the head of the screws nice and level with the skin. I would keep the amount of times you do this, generally on a tight spot where you can't get the solid rivet in there. I also did this on my tips. I dimpled for the cs4-4 and than hit it with the cutter just a little to put the -4 down just a little, than filled it flat and made it nice looking.