Dimpling with rivet gun

Is this a dumb idea? I just shaved my c frame ram down to fit the rivet gun. The dimples look great in my opinion. I'll post a picture as soon as I figure it out. Just curious if anyone else does this or if it's not smart!

Ive heard of people doing that, I'm not really sure what the advantage is?

Picture



Would these be good or over dimpled? Disregard the burrs

There's really probably no advantage. I found it to be quick and relatively effortless. Very loud though as you might expect.

For one thing, you don't have to whack it with a two-pound hammer, the way I do.

Dave

Hammee

David Paule said:

For one thing, you don't have to whack it with a two-pound hammer, the way I do.

Dave

Click to expand...

Or blow up a hammer!

It's difficult to judge proper dimpling from a photo, but they definitely don't look overdriven. What do the driven rivets *feel* like? Proper dimples should leave the transition from the shop head to the skin barely detectable. Drag your finger nail lightly across the joint; you should jut barely detect the edge of the rivet without hanging your nail on the rivet. Slide your finger tip across it; you should not feel any waviness in the skin; it should feel flat. (Poor riveting technique will obviously affect that...)

If the skin is under-dimpled, the edge of the dimple will be rounded and the rivet will stand a bit proud of the surface. You'll be able to hang your nail in the edge.

I've used a rivet gun to dimple in situations where it just couldn't be done with regular tools (you can actually buy a die holder made for a rivet gun). The gun trick works great if you find a spot that's under-dimpled, or two layers that don't perfectly align (cocking the rivet at an angle). Putting the female die in a bucking bar, you can re-dimple with a light burst on the gun. Male die in the gun, or just put a rivet in the hole (tail in the female die) & hit it with the mushroom set.

But for anything that lends itself to using the C frame, a rubber mallet would probably be faster than the gun. Just faster to get the work positioned correctly, grab the mallet, & whack it a couple of sharp blows.

Charlie

After I messed up a couple of hammers like Larry, I began to use the rivet gun method with my C-frame . . . A couple of taps and the dimple is perfect and consistent . . . Move on to the next hole.

Using the gun with the C-frame works particularly well for dimpling nutplates. I have a set of dies with the female side modified to fit closer to the threaded stub. It takes a couple of medium length pulls on the trigger, but you get much better results than with a hammer (or a squeezer for that matter).

Input

Thanks for the input. I'll test it through the empennage build and let you know how it works...

Danger-possible damage to skin

Keep in mind that the rivet gun hits several times a second (a 2X gun hits at about 40 blows/sec at full throttle, 3X 35 blows/sec). That means you might be hitting your skin after the dimple is formed and therefore actually thinning out the material round the dimple. I believe forming the dimple with the hammer minimizes the possibility of damaging the skin over using the rivet gun.

However if you want a tool that forms the dimple consistently, quietly and with minimal effort I would recommend the DRDT-2 (shameless product plug).

Its a good skill to have when there is no other way.
Use it as last resort.
Turn the pressure down and just give it a quick burp on the throttle.
It will make a nice sharp dimple.

Take your time to make sure the dimple sets are perfectly perpendicular to the work or you will leave a "smile" in the sheet.

**EDIT** I reread the thread and now realize the OP was talking about using a rivet gut to drive his C-Frame ram. My comments above are related to going "cowboy" with a gun/set and buckbar/set so .... not directly applicable to his comments.

also, take a straight edge to those rivets, if they are below the surface, the rivet will not set properly, like a too deep CS....A hem....just saying......

Yes I hate to tell you but those are too deep. If you must use your rivet gun there are special dies and technique however they are normally only used when there is no option. Like anything else the C Frame tool just takes a little practice but it does a good job when you have the hang of it.

Dimpling nutplates

David Lewis said:

.....

Using the gun with the C-frame works particularly well for dimpling nutplates. I have a set of dies with the female side modified to fit closer to the threaded stub. It takes a couple of medium length pulls on the trigger, but you get much better results than with a hammer (or a squeezer for that matter).

Click to expand...

Much easier, and quicker, to simply use NAS-1097 small head rivets with countersunk holes for nutplates.

Nutplate rivets aren't really structural and don't need the slight extra strength of dimpling. They only need to stop the nutplate from turning.

az_gila said:

Much easier, and quicker, to simply use NAS-1097 small head rivets with countersunk holes for nutplates.

Nutplate rivets aren't really structural and don't need the slight extra strength of dimpling. They only need to stop the nutplate from turning.

Click to expand...

But if you dimple the nutplate rivet holes along with the prepunched rivet holes in the sheet, the dimples make dandy alignment jigs to keep the nutplate centered without special tooling.