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Proper Riveting Technique

challinan

Active Member
Hi Folks,

I am back to work after an 8-month delay (move, new job, new workshop.)

Having finished the VS and rudder, I'm working my way through the horizontal stabilizer. All of my rivets in the skin are leaving what look like tiny scratch marks on the skin next to the rivet hole. I am using a shiny new mushroom set - it has no scratches.

Is this normal/acceptable? If not, what might I doing wrong?

Picture link is here:
https://goo.gl/photos/56gyFd3ijFz7mUyS8

Thanks,

Chris
 
Totally normal .. you can use rivet tape if you want to minimize the burnishes .. but they will go away during paint prep.
 
Also, looks like you're over dimpling or possibly using the wrong die? The rivets should be flush with the skin, you shouldn't be able to see any of the dimple when you're finished riveting or even when you just set a rivet in to the dimple.
 
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The photo seems to over exaggerate the depth of the rivet. They are basically flush, maybe microns below the skin surface. After I use the dimple die, I received advice to very lightly run a countersink bit by hand to clean out the hold before bucking the rivet. That's what I've been doing. When I don't do that, sometimes the rivet sits high with a slight gap - I think I'd rather have the scratch than have the rivet sit high.

Any other advice appreciated ;)

Thanks,

Chris
 
After I use the dimple die, I received advice to very lightly run a countersink bit by hand to clean out the hold before bucking the rivet. That's what I've been doing. When I don't do that, sometimes the rivet sits high with a slight gap - I think I'd rather have the scratch than have the rivet sit high.

Any other advice appreciated ;)

Thanks,

Chris

My advice is be very cautious doing this.
If you are dimpling properly with quality dimple dies, this should not be necessary.
The risk is that if you go just a thousandth or two, too deep, you could be setting rivets that are flush with the skin surface, but are not tight in the bottom of the dimple (not good from a structural standpoint).
 
After I use the dimple die, I received advice to very lightly run a countersink bit by hand to clean out the hold before bucking the rivet.

Deburring takes place after you drill the hole, either for match drilling or final drilling. You wouldn't really want to debur after you dimple as there would be no way to get the dimpled side without affecting the walls of the dimple with the tool you are talking about.

We were also given that same tool for deburring and nothing wrong with using that tool, just conservatively and before dimpling.

I think you may be making a simple procedural error here .. debur before dimpling.

We ended up using these for deburring, a bit easier and they don't tend to take off a ton of material like the countersink bit will .. https://www.aircraftspruce.com/catalog/topages/speeddeb.php?clickkey=9772
 
The photo seems to over exaggerate the depth of the rivet. They are basically flush, maybe microns below the skin surface. After I use the dimple die, I received advice to very lightly run a countersink bit by hand to clean out the hold before bucking the rivet. That's what I've been doing. When I don't do that, sometimes the rivet sits high with a slight gap - I think I'd rather have the scratch than have the rivet sit high.

Any other advice appreciated ;)

Thanks,

Chris

From the pic it looks like something is wrong with the dimple die. I would ask you contact a tech counslor in the area and have him take a look.
I never had to run the countersink in the dimple to get them flush. The only time i did this was when instructed. Sometimes the rivet appeared to be hi before setting. But they all came down once set. JMHO
 
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Thanks, Scott.

Andy advice for how long I should expect a good set of dimple dies to last before they should be replaced? They sure take a beating using the dead blow hammer and the C-Frame.

Chris
 
I had same issue on scratches. No big deal if you plan to paint as it will ALL get scratched prior to paint (scuffing), but still wanted it to look good in my garage while building.

Started putting blue painters tape on my mushroom set head. Last about 30-50 rivets between putting new tape on. No scratches. Keeps me happy.
 
Blue painter tape on mushroom and

Black electrical tape on rivets and you will be pro:D
 
I am with bkervaski. The photos make it look as if the dimple (die) is too big in diameter. The witness marks from riveting I have seen before, but the final rivets and the dimple don't look right to me. The band around the rivet indicates a dimpled surface, but the rivet should fill the dimple completely. I would definitely try a second set of dies for comparison. Photos can be deceiving, I know, but that looks like more than a few microns.
 
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