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  #1  
Old 04-18-2010, 06:50 PM
redoxide redoxide is offline
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Default Riviting !

This might not be a metal shaping question but perhaps something that a lot of us might encounter, RIVITING...

Ive started to build a 30s special and was hoping to add some rivits to hold the thing together and add some charachter.

Im prety sure there will be a formulae for riviting like most other metalworking opperations.

Question is, whats the formulae for the following:

Selecting the proper rivit

Selecting the correct shank size

selecting the correct head diameter

selecting the proper length and the correct spacing .

Once the proper rivit is selected whats is the proper method of peenig them,

Im looking to use some roundhead rivits on this job and would like to have both the manufactured head to stay undamaged and make the peened end a duplicate of the other end.

I know you need to use the appropriate rivit snap to fornm the head on the blank side, but what do you use on the preformed side to stop the head being mashed?

The materials im using are 1.6 mm aluminium sheet, also the odd length of 3mm ally angle to which some areas of the 1.6mm sheet will be rivited to.

other bits will just be 1.6 rivited to 1.6 . ( rear chassis covers )

Ive got some manual rivit sets and snaps and a small selection of air tool rivit snaps, probably all the wrong size for what I need...most likey..
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Old 04-18-2010, 06:55 PM
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jhnarial jhnarial is offline
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I think it is a good topic, It's about the same as welding panels.

Look what Kenb has done with it.I would like to learn a little about it myself.
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Old 04-18-2010, 06:58 PM
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Kerry Pinkerton Kerry Pinkerton is offline
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I'm sure that the airplane guys can talk to this. Most are still returning home from SunNFun but I expect they'll check in soon.
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Old 04-18-2010, 07:11 PM
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I talked to friend of mine that was at Sun n Fun and he went to a riveting seminar while he was there. Said it way very good.

Mr. C thanks for helping Michael, he was impressed with what he saw.
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Old 04-18-2010, 07:40 PM
Charley Davidson Charley Davidson is offline
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I thought about going to one of the workshops on riveting but mig and tig welding seemed much cooler so I skipped on it. But I think I'll hit it next year.

I used to work in the aircraft industry and we bucked rivets all the time but it's been years, also with my interest in buses I should refresh that area.
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Old 04-18-2010, 07:48 PM
Sean Sean is offline
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Default Rivets

I'll try to address each selection criteria as it was asked.

Selecting proper rivet:

Rivets are usually selected by their material. The effort is to select a rivet of the same material as what you are riveting in order to prevent dissimilar metals from corroding. In this sense you would select steal rivets for steal, aluminum for aluminum, magnesium for magnesium, etc.

The next selection criteria would be strength, structural rivet for structural parts. Some of the super high shear strength rivets require special annealing before use.

The most common structural aluminum rivet is the AD series of rivet. These ones are ready to use right out of the box so to speak.




Proper shank size:

The basic rule of thumb for shank size is 3 times the thickest sheet you are riveting. ie. if you are riveting together .040 - 3x.040=.120 so you would use a 1/8 rivet


Proper head diameter:

Head Diameter is a function of the size of shank. The formed head of the rivet should end up being 1.5 x the diameter and .5 diameters in length.

Length:

The rivet needs to be long enough to produce the above mentioned formed head. There is a mathematical equation that will come up the exact length you need to get the perfect rivet tail but honestly I haven't measured a rivet in years, probably not since school. Once you've done enough you can just eyeball it and know if it is right or not. I think the length might be 1.5 x diameter to start with. But basically if the formed heads are too small, start longer, and if they bend over like nails, start shorter.

Spacing:

Spacing from the edge of the sheet is not less than 2 x dia. and usually no more than 5 x dia. Too little spacing and the holes will tear out the edge and too much and the edge will curl up. usually aim for 2.5xdia.

Spacing between rivets is usually 4xdia. to 12xdia. Bell hellicopters prefers about 8xdia. spacing between rivets. 4d will give you a really rivety look if thats what you are after
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Old 04-18-2010, 07:57 PM
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Marty Comstock Marty Comstock is offline
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Great info Sean, thats the best simple rivet info I have seen yet, lets see if that can be libraried!

Marty
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  #8  
Old 04-18-2010, 08:04 PM
Sean Sean is offline
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Default Forming the head.

The head is most commonly formed using a rivet gun with the appropriate set driving against the manufactured head of the rivet and holding a bucking bar
(block of steal) against the tail. This sets up a reaction like those swinging steal ball desk toys or since this is a metalshaping forum hammer and dolly. Force put in by the gun gets reflected back by the bar and the rivet tail flatens.

The set is cupped to fit the head of the rivet so as to not mash it.
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Old 04-18-2010, 08:19 PM
TheRodDoc TheRodDoc is offline
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I was taught to choose the rivet size and spacing by the shear flow of the sheets to be riveted.

The shear flow is in linier inch measurement down joint. (sheets pulling apart)

determine the rivet strength and place sufficient rivets to handle the calculated shear flow.

Example:

Let's say you determine that the shear flow on the sheets is 600 pounds per inch and you have a rivet with a shear strength of 400 pounds, you will have to place these every .667" to handle the load.

If on the other hand the rivet you choose has a shear strength of 600 pounds, you can place these on one inch centers.

And if the rivet you choose has a shear strength of 200 pounds The spacing will be .333".
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  #10  
Old 04-19-2010, 03:15 AM
redoxide redoxide is offline
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Cheers Sean, that pretty muh covers exactly what I needed to know. I need to order some rivits for this job so now I can calculate the proper size to make the job look right.

Daft question, ( ithink i know what the answer will be) will the bucking bar have a recess in it suitable for the manufactured rivit head?

can these be easy purchased or is it just a case of making up what you need..

Thanks again.
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