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Rivetting

The Captain

The Captain

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Hi- making a flight case at the mo: using a hand rivet gun and 4.8 x 20mm rivets, once squashed into hole the rivet stems remain stuck to the gun: trying levering nozzle away just makes a dogs dinner of the soft alu rivet- so Ive painstakingly hacksawed thru each rivet shaft; once gun off and rivet shaft tapped back thru (and off) alls seems ok. My Q: is the shaft meant to remain, or if disloged will the fattened end of the rivet without the shaft stem bit be strength enough? thanks Captain
 
Don't know if I'm reading this situation right, are you just operating the rivet gun until the rivet pulls tight against the metal you are riveting?
You are supposed to keep squeezing the rivet handle until the rivet shaft breaks off from the ali part of the rivet.
Hope this helps

Jeremy.
 
... and makes a "pop" sound as in "Pop rivet"?

It's easy to assume things are obvious but I can remember doing my first bit of pop rivetting and discovering the fun of it all. The folded end is man enough for the job without the shaft.

Once you have installed the rivet the other end does (mostly) stay inside the squashed end but can be pushed out through from the top to reveal the hole where the shaft was. I suggest you do this to avoid future loose shrapnel. Have fun.
 
What I meant was; squeezing gun fully bollocks hard it ain't poppin orf.. so I have to saw it off and tap it through/ out. I was wondering if the usual popped shaft end sunk into hole and lodged at fattened rivet base was part of its inherrent design for strength, ie removed= bad? I have much weight top handle is holding see.. this jobs been a right pop tart so far.
 
Hi Captain
After compressing the rivet, release the gun, put the nose of the gun almost upto the rivet and squeze again.
If this doesn't cause the rivet to pop then you have a faulty gun, faulty arm or are using rivets too short for the thickness you are trying to secure.

Good luck
Gareth
 
It really does depend on the type and quality of the rivets & pullers you are using as to where and how the stem breaks when you form a blind rivet. Some are designed so that once the head has formed the mandrel falls out leaving a bulb emedded in the rivet, in others both bits fall out leaving a hole through the middle.

4.8mm rivets are quite big ones and you will need a fair amount of grunt behind them , using a decent quality puller

You also need the correct grip length, it is usual to have about 1½ to 2 x Diameter of the rivet poking out the other side with which to form the rivet tail.

If you are rivetting particularly soft material, or composites ( carbon fibre, GRP, Kevlar, etc ) it is often advised to also add a washer on the tail of the rivet to help prevent it pulling through.

Getting back to your original query, follow TTiamat66's sound advice, squeeze the rivet as far as it will go and if the stem doesn't break , open up the pliers fully again, push the nozzle down onto the head and take another bite.
 
Mmm- I guess Ive a faulty gun, tho Ive stripped it down and all bits seem fine and ok quality. I simply cant open up pliers to give it another go, as rivet shaft is nr welded in the gun's jaws- all the obvious things to do I did try. Oh well it took 4 times as long (120 rivets!) but as long as the mandrel stem bit is not neccessarily needed for a strong join I think Im ok. Big bastard rivets they were; not a job I wish to repeat soon. Thank you for replies. Capn
 
The Captain said:
Mmm- I guess Ive a faulty gun, tho Ive stripped it down and all bits seem fine and ok quality. I simply cant open up pliers to give it another go, as rivet shaft is nr welded in the gun's jaws- all the obvious things to do I did try. Oh well it took 4 times as long (120 rivets!) but as long as the mandrel stem bit is not neccessarily needed for a strong join I think Im ok. Big bastard rivets they were; not a job I wish to repeat soon. Thank you for replies. Capn
Click to expand...

TBPH, the rivets you were using were particularly big ones, especially given the project you were doing.
Aircraft pressured skins (some of them only 0.025" thick in places ) are usually put together using 1/8" (3.2mm) or 5/32" (4mm) reduced head, countersunk rivets and that is with upto 6 or 7 psi acting on them cyclically - even too scary for me to think about sometimes...
 
The Captain said:
I simply cant open up pliers to give it another go, as rivet shaft is nr welded in the gun's jaws- all the obvious things to do I did try.
Click to expand...
I had the same issue when I was assembling a garden shed. The simple solution was to use a small hammer to tap the back of the rivet gun to dislodge the binding and bring the nose cone in closer for another bite. Worked every time.

James
 
Totally right Sid, I opened the pack and thought 'Ive a job on here for sure..' I was just matching rivets had been used on the flight case before (I chopped up/ reused handles, alu edge brackets, corners etc.) Firstly it needed a few 4.8 x ~10mm you see, which popped off fine having narrower stems (?-I expected same stem size with the 4.8 x 20mm).. Ive got little skin on me hands left now! bloody hard work that..
 
James said:
I had the same issue when I was assembling a garden shed. The simple solution was to use a small hammer to tap the back of the rivet gun to dislodge the binding and bring the nose cone in closer for another bite. Worked every time.

James
Click to expand...

Bugger. If only Id thought of that.
 
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