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Riveting
Julian B - 19/3/04 at 08:32 AM

Hi

Are there any alternatives to pot riveting? Although pot riveting leaves a nice finish on the top surface the underside looks cack. What did/do they use in the aircraft industry to get those nice countersunk rivets? Obviously pot riveting is fine in some places but in others it would be nice if there were a more elegant method.

Cheers all


Staple balls - 19/3/04 at 08:53 AM

what are you riveting to where? different methods are more suitable to different places.

all my internal panels (apart from the tunnel) will be glued on


Mix - 19/3/04 at 10:18 AM

Aircraft rivets are generally set using the reaction process. The head of the rivet is hit using an appropriatly shaped punch, (dolly) whilst a heavy smooth metal block is held on the tail. This forms a fairly flat cylindrical head (on the tail). Alternativley the rear of the work can be countersunk and the rivet formed into the recess to give a flat surface on both sides. If you have a compressor and an air chisel you can adapt them for setting solid rivets by either reducing the compressor output pressure or restricting the flow to the chisel. For countersunk head rivets you need to adapt a chisel so as it has a circular end of about 25mm in diameter with a very slight domed profile and smooth surface.

Hope this makes sense

Mick

[Edited on 19/3/04 by Mix]

[Edited on 19/3/04 by Mix]


Peteff - 19/3/04 at 10:38 AM

where will you see the undersisde of the rivets? All mine are inside the RHS tubing where you can't get at the backs to peen them over


David Jenkins - 19/3/04 at 12:19 PM

quote:
Originally posted by Mix
If you have a compressor and an air chisel you can adapt them for setting solid rivets by either reducing the compressor output pressure or restricting the flow to the chisel. For countersunk head rivets you need to adapt a chisel so as it has a circular end of about 25mm in diameter with a very slight domed profile and smooth surface.



Mick,

What sort of air pressure are you talking about - I'd like to try this with my air hammer.
Did you take an ordinary air hammer bit and hack it around?

David


Julian B - 19/3/04 at 12:19 PM

Sorry POP rivets.... doh

I was clearing out the garage and i came accross an alli boot cover i had made up for my old car. Yep most of it is into tubing so you dont see the back of the rivets.

I still dont see how you get the tension with the aircraft syle rivets as you do with the POP rivets. Perhaps i am being a bit stupid!


Jasper - 19/3/04 at 12:55 PM

I've used countersunk rivets, you need to buy the appropriate countersinking drill bit to go wth them


Mix - 19/3/04 at 01:04 PM

David

It's difficult to give a pressure as it depends on how efficient the air chisel is. Air riveters have a much 'softer' action, reducing the pressure on an air chisel will however give an acceptable comprimise. Reduce the pressure until when the chisel is operated against a block of wood it makes a similar sound to fairly firm rapping on wood with your knuckles.

Yes just adapt a bit or get something turned to suit.

Julian

Solid rivets are stronger in both shear and tension than normal pop rivets due to the increased cross sectional area. The action of setting them sqeezes the joint together and expands the rivet into the hole much more efficiently than a pop rivet.

Mick


stephen_gusterson - 19/3/04 at 01:08 PM

just look at a ship for example, gadzillions of blind rivets - and they dont leak either - so must be a tight fit.

Still amazes me how many rivets there are in an aircraft wing - looking outa the window last week, they were double stagered rows, approx 2 ins between each row's rivets. (747)

atb

steve


Julian B - 19/3/04 at 02:35 PM

I thought that iron rivets on ships were put in hot and the cooling and contraction of the rivets pulled the plating in tight


stephen_gusterson - 19/3/04 at 09:55 PM

possibly - but the contracting is actually gonna give a loose fit in the hole - must be the hammered head that seals it.

atb

steve


suparuss - 19/3/04 at 10:01 PM

what is it you are fixing then? have you considered bolts? if there isnt enough depth to thread the hole you could use expansion inserts, which dont look as bad as rivets from the rear.


Peteff - 19/3/04 at 10:40 PM

Ships were built with rivets peened over from both ends like boiler construction. Watch Fred Dibnah, he'll show you. Some poor bugger had to be at the back of the plate with a rivetting gun to round the head over. Ships haven't used rivetted construction since about the 40's have they?


Spyderman - 20/3/04 at 11:04 AM

quote:
Originally posted by Julian B
I thought that iron rivets on ships were put in hot and the cooling and contraction of the rivets pulled the plating in tight

The rivet is put in hot and the other side is hammered over.
Then when the thing cools it clamps the plating tighter.
There is more shrinkage in it's length than it's diameter.


DaveFJ - 20/3/04 at 05:09 PM

The reason for fitting 'ship' type rivets hot has more to do with the material itself....

an average rivet in a ship is huge and would be almost impossible to reaction. Heating the rivet simply makes it softer.

when using conventional riveting techniques you should always have the the materials clamped firmly together. the rivet fills the hole provided but will not 'clamp up' like a blind rivet would. A well formedrivet will retain the level of 'clamping' when the grips are removed. As an aside I would not recommed using the spring type clecos when using solid rivets, they do not provide enough pressure. Go for the manual thumb screw type instead.

saying that it is always best practice to ensure that materials are firmly clamped together before blind riveting as well.......


Jasper - 20/3/04 at 05:21 PM

Hey boys, I'm sure there is a forum out there for people building ocean liners in their back gardens - BUT THIS ISN'T IT


Mark Allanson - 20/3/04 at 06:05 PM

Speak for your self, I have just laid down the keel for a replica of the Queen Mary, cannot decide to use Pinto of Zetec though


Carl.H - 20/3/04 at 06:35 PM

Pinto for the anchor and the zetec to power it


britishtrident - 20/3/04 at 06:50 PM

Many many varietys of pop rivets you can use stainless steel closed end for bit that show and need strength --- expensive ! Plain steel are more suiable for parts that are to be painted.

Countersunk are only available in aluminium alloy.

See http://www.rivetwise.co.uk/product/index.htm

[Edited on 20/3/04 by britishtrident]


type 907 - 21/3/04 at 09:41 PM

Hi,
I'v been looking at Clecos, they look useful, http://www.lightaero.co.uk

Loads of bits & bobs on this site.

Paul G


andrew-theasby - 22/3/04 at 01:30 AM

There are loads of different rivets used in the aircraft industry. The solid rivets arent much use on our cars as you need to get to both sides and theyre solution treated then age harden so you only have 2 hours to get them in or theyll crack. The blind ones can be countersunk or raised heads but most, ie cherry's, mbc's olympics etc need a different gun to a normal pop gun as they have locking rings or odd sized mandrells. The best ones to use are the ordinary steel 100 degree countersunk ones that look like a normal pop rivets but you need to either punch the ball part of the mandrell out or araldite it in. They can then be milled flush and invisible when painted. its best to use some kind of sealant between the joints to avoid fretting as the whole idea of rivetting is to allow things to move slightly and it stops disimilar metal corrosion. The top material needs to be at least 1mm or the csk will break through and the hole needs to be fairly accurate in diameter too. Hope this helps


DaveFJ - 22/3/04 at 01:08 PM

quote:
Originally posted by andrew-theasby
The solid rivets .... and theyre solution treated then age harden so you only have 2 hours to get them in or theyll crack. . The best ones to use are the ordinary steel 100 degree countersunk ones that look like a normal pop rivets but you need to either punch the ball part of the mandrell out or araldite it in. They can then be milled flush and invisible when painted......the whole idea of rivetting is to allow things to move slightly and it stops disimilar metal corrosion.



Remind me to never let you near an aircraft..............

no,no,no,no and err no!

Cheers

Dave (an Aircraft Engineer)

[Edited on 22/3/04 by protofj]


David Jenkins - 22/3/04 at 01:30 PM

quote:
Originally posted by protofj

Dave (an Aircraft Engineer)



Dave,

Perhaps you can answer a vaguely relevent question - I once went into an RAF aircraft maintenance hanger in St Athan, and saw a technician rivetting an ali skin onto the tail of a VC10 (one of their tanker aircraft).

What puzzled me is that he was using an air hammer on a fully closed-up wing (i.e. no backing anvil) - how did he manage that? The only thing I can think of is that there was an inspection hatch that I couldn't see - but I'm sure there wasn't!

cheers,

David


DaveFJ - 22/3/04 at 01:47 PM

David,

Little idea - sorry.....

the process does require a reaction block to be placed behind the rivet being worked. I can only assume that there was a block being held in by some sort of clamp ?

I have seen a similair situation where it would have appeared that there was no reaction block, this was whilst riveting the tail boom of a helicopter. there was in fact a guy (the smallest on our crew) tucked up inside the boom and at full stretch he could just get onto the back of the rivet....
took bloody ages to get him back out though


andrew-theasby - 23/3/04 at 12:33 AM

Thats what i do for a living. Whats wrong with what i said about the solid rivets??? The guy on the wing skin might not have been putting rivets in, but more likely putting hi-tigue bolts in. these are an interfernce fit, so thats why he was using the rivet gun to hammer them in. There used to harden the metal arond the hole (ie HIGH faTIGUE bolts)


Mix - 23/3/04 at 09:52 AM

Ah! military men I'm guessing

Mick