Rivets, and Riveting

[lynnl]

Other than pop rivets, which of course I've often used, installing rivets has always been something of a mystery to me.

I was watching a segment on making aluminum boats on "How it's Made," and the guy was just dropping round head rivets into the pre-drilled holes, and hitting each one quickly with a pneumatic rivet gun for a second or two.
I couldn't see what sort of motion or action (rotary/reciprocating?) was taking place at the head of that gun, nor hear anything (due to that da#@$ music (noise) in the background).

I also couldn't see what was on the back side of the aluminum panel(s), but he was moving from one to the other too quickly to be repositioning any sort of bucking device.

Can anybody explain how that would've worked? There has to be some type of "anvil" on the back side, ...doesn't there?

How is that done on aircraft where you're putting rivets into some very wide panels?

[topct]

Could you see anyone on the back side. There must have been someone with a buck moving it along with the guy operating the gun.

I went to the Boeing riveting school a long time ago and that's what we did. It could be done by one person if you could reach around with the buck. But if I remember right we would just take turns. Boring horrible job.

Evan would know more.

[JoeCB]

Yes, all conventional rivets must be backed up before the end is upset. For most sheet metal work, obtaining a tight joint requires a preliminary step ... "setting" prior to upsetting the stem. A simple tool with a hollow shaft is driven over the rivet stem to ensure that the head is seated and the metal sheets are tight together. Next the stem is upset using a hand tool called a "snap". The "snap" has a concave end that forms the end of the rivet. Now, all this may be a bit fancy for the average job. likley the "back-up" and "snap" are just flat end tools.
My father was a tool maker at Ford's Willow Run Michigan bomber plant during WWII, That's the plant that had the distinction of producing one B-24 heavy bomber per hour at peak prodiction. Ford recruted teams of "little people" (midgets - to be non PC) to get into the tight wing structures in order to back-up the rivets. The "little people" tended to hang around together, dad said that at shift time it was sort of like watching a circus troop walking in.
Joe B

[Evan]

As explained is pretty close. Somebody was holding a bucking bar on the back side. The "snap" is installed in a rivet gun which is about the same as an air chisel but with a faster and lighter impact rate. To set the rivets in the hole tightly I would usually drill a hole in the bucking bar in a convenient location where a couple of smacks with the rivet gun would set it tight in the hole. Then place the bar over the rivet and hammer it the correct amount. This takes far longer to explain than it does to do.

These are various bucking bars from my collection:



It's a little different on building aluminum boats because the material is a lot softer than 2024 aircraft aluminum. The rivets are much softer to avoid cratering the metal around the rivets. I have built all sorts of things by way of rivetted construction. At the shop I worked at in Sydney on the Island we build whatever came in the door in the summer time. Everybody was out flying during the summer. Among other things I built the complete chassis for a Can-Am car, a steel restaurant hood and a large ferry tank for a bell 212 helicopter.

On the race car I redesigned the fuel tanks on each side to have double walls with urethane foam filler. The original chassis was made of 6061 sheet metal and pop rivets. I changed that to .040" 2024 instead of .063" 6061 and riveted it all with solid aircraft rivets. The driver later reported the car was much stiffer and handled better. It also saved about 50 lbs weight.

I still use rivets for assembling many projects including my recent 10" telescope.

[lynnl]

On that boat building, the guy with the air tool, I could see, was NOT reaching underneath to the back side. He was using the non-tool hand to stick the rivets in the holes.
He was working at about waist height, so if someone was underneath doing the bucking, then he must've been knee walking. ...or else he was down in a pit; I really couldn't determine that. ...or maybe he was a midget too.

Also, as fast as he was moving from one rivet to the next, it would not seem to permit enough time for a partner to get re-positioned on the next rivet. Though I suppose with enough practice and experience they could get their actions synchronized pretty closely.

Regardless, it was a nice looking boat -- a Prince Craft. Combination fishing/pleasure, with a 225HP Mercury OB mounted on the one they showed on the water.

[firbikrhd1]

These are various bucking bars from my collection:

Your "bucking bars" look much like body dollies. If they are body dollies they were designed for a different purpose than bucking rivets but should serve the purpose just the same.

The only reason I mention this is that should the OP attempt to find "bucking bars" he may have some difficulty but finding body dollies should be a piece of cake.

[Evan]

Also, as fast as he was moving from one rivet to the next, it would not seem to permit enough time for a partner to get re-positioned on the next rivet.

He was just putting the rivets in the holes and setting them in place. The skin on some of those boats is thick enough to take that. It depends on the boats a lot. Some are dead soft and anything will make a dent. My Grumman canoe is made of .032" 2024 aircraft alclad aluminum and even that thin is guaranteed against puncture for as long as you own it. I have tested that and it has held up. Me and my brother were caught in a thunderstorm blowing down the lake and we had no time to pick a good spot to take cover. We hauled the canoe with full gear up on nasty pointy rocks. It left some good scratches and a few dents but no holes. I always carry a patch kit but have never needed to use it.

[Mike Folks]

http://www.rivetsonline.com/

[Evan]

This is my supply of aircraft rivets. Aircraft Spruce sells nice assortments for reasonable prices.

[lynnl]

He was just putting the rivets in the holes and setting them in place. .

What do you mean by "setting them in place?" ...simply putting them in position? Or does that term have a more specific meaning in this useage?

After he placed each one he would then apply that air tool on top of the rivet head, and something would then take place. But as I said, I couldn't tell if it was some rotary motion or a hammering action. These were in a longitudinal line, along overlapping seams, so they were not going into a heavier structural member ...at least not all of them.

Are you saying Evan, that there was a later bucking operation to be performed?