Rivet setting

Looking for a quick and easy solution of fixing many plates to the ends of steel supports of assemblies I produce, I have considered the use of rivet
snaps to dome the head of said support (reduced dia from 8mm to 6mm where it passes through the plate) giving a neat and quick solution to the task. ( as opposed to the current way of doing this, peening the end over with a hammer)
I never really understood the process of "setting" the rivet ? Or is that only for soft iron rivets when building railway engines ? The old small rivet snaps I have, seem to have the domed bit and a plain drilled hole on the end?
Is EN1A at 6mm likely to be very co-operative to cold head domeing? Bob
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On Tue, 16 Oct 2007 08:46:42 +0100, "Emimec"

Riveting is a double ended process the support will have to be held whilst it's riveted over. The setting is done by the bit with the hole in driving the plate onto the head of the rivet so there are no gaps then using the domed bit to perform the rounding over.
You will have to try this but I'm guessing it will take more force than peening.
Without seeing the part can the design be changed to drilling a hole in the end instead of reducing and fitting one of those spiral drive screws in like the ones used to secure name plates to machines?
These can be had in different sizes and lengths, domed headed, look nice and are a total bastard to get out once driven in.
Just an idea.
.
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Emimec wrote:

Blind rivets?
Nick
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Photo to follow ( If I survive the dentist !! ) Bob
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On Tue, 16 Oct 2007 09:25:24 +0100, "Emimec"

You may survive but your bank account might be buggered
Charles
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Emimec wrote:

As long as he is using stainless rivets, no problem.
Nick
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Photo's of the old American assembly.
http://i208.photobucket.com/albums/bb94/emimec/IMG_3471.jpg
http://i208.photobucket.com/albums/bb94/emimec/IMG_3470.jpg
Escaped the dentist for less than 50, I really am in the wrong business !!!
The two fixings in question are either side of the circlip. I may go back to Yankee way of thumping them with an "X", or maybe drilling a small hole and thumping under the flypress with something like a lathe centre shape. Bob
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Old dentists burrs are very good engraving tools and they'll be secondhand after he has used them on you :-)
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Bob, the traditional method used by the American assembly is one of the simplest and one of the most effective. While I'm no world expert on riveting particularly with steel rivets, as ex aerospace rivets were daily "bread and butter" for many years.
When you set a rivet there are three aspects which are critical to the holding power. Firstly the plate (or plates) has to be tight against each other and the rivet head or shoulder in your case. This is where the "set" (with the plain hole) normally comes in and snugs all of the surfaces up against each other. When there is more than one plate it is quite possible without using the set properly to get the rivet to expand between the plates and create a gap. Secondly and often forgotten, the rivet needs to swell inside the plate holes to fill the hole completely. This itself provides a portion of the holding power. The head then needs to be formed and if properly completed will force the two plates closer together. The shape of the head is important as it can with the normal round head; increase the surface area providing the closing force. From your pictures this additional area is not required and the cross pattern head obviously provides the security necessary and is much easier to form. In aircraft many rivets are formed like that just by axial blows which expand the rivet tail and provide adequate holding power. Obviously the rivets are softer and form more easily. The cross pattern punch method you show is used where the rivet is of a harder material and is likely to crack at the edges if formed by a dome head rivet snap or expanded too much with the ballpein hammer.
Of the methods you mention, drilling and opening out with a centre point is likely to do two things; firstly the axial load provided by the punch on a point contact will not provide enough axial force to swell the rivet into the hole fully. Secondly the pointed punch if asked to do too much is likely to crack the rivet tail and leave it both relatively weak and unsightly. The cross punch does two jobs, the flat surface at the bottom of the cross (on the punch) provides sufficient axial force to "upset" the rivet shank and grip the hole and the cross expands the tail in four equal portions beyond the hole diameter providing positive grip. To be honest, just hammering the end of the rivet axially to both upset and produce an increased diameter tail would be better than the pointed punch. While you see rivets that are formed with a central hole on brake shoes etc, they are usually formed by spin riveting. In aircraft this hammering is normally done by an air hammer with a dome snap set against the rivet head and a square steel "reaction" block held against the tail to form it. .
I'm not sure if I have explained this very well or am in fact trying to "teach granny", if so, I apologize. I see nothing wrong with the original method used although it will require a fair bit of axial force on 6mm steel to form correctly. We would have used something like this:
http://www.tooled-up.com/Product.asp?PID=27888
With a well chosen hole diameter and correct length rivet tail the single operation should take no more than a few seconds to complete and will hold very securely indeed. In short, pop the plate on; a quick "tap" on the end to swell the rivet slightly and grip the hole followed by the "set" to ensure tight contact and then some smart axial blows to form the tail - job done. If you want it to look posh the last axial blows could be with the use of a dome snap but as I have said with hard rivet material that can be problematic cold.
Regards
Keith
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Bob, the traditional method used by the American assembly is one of the simplest and one of the most effective. While I'm no world expert on riveting particularly with steel rivets, as ex aerospace rivets were daily "bread and butter" for many years.
When you set a rivet there are three aspects which are critical to the holding power. Firstly the plate (or plates) has to be tight against each other and the rivet head or shoulder in your case. This is where the "set" (with the plain hole) normally comes in and snugs all of the surfaces up against each other. When there is more than one plate it is quite possible without using the set properly to get the rivet to expand between the plates and create a gap. Secondly and often forgotten, the rivet needs to swell inside the plate holes to fill the hole completely. This itself provides a portion of the holding power. The head then needs to be formed and if properly completed will force the two plates closer together. The shape of the head is important as it can with the normal round head; increase the surface area providing the closing force. From your pictures this additional area is not required and the cross pattern head obviously provides the security necessary and is much easier to form. In aircraft many rivets are formed like that just by axial blows which expand the rivet tail and provide adequate holding power. Obviously the rivets are softer and form more easily. The cross pattern punch method you show is used where the rivet is of a harder material and is likely to crack at the edges if formed by a dome head rivet snap or expanded too much with the ballpein hammer.
Of the methods you mention, drilling and opening out with a centre point is likely to do two things; firstly the axial load provided by the punch on a point contact will not provide enough axial force to swell the rivet into the hole fully. Secondly the pointed punch if asked to do too much is likely to crack the rivet tail and leave it both relatively weak and unsightly. The cross punch does two jobs, the flat surface at the bottom of the cross (on the punch) provides sufficient axial force to "upset" the rivet shank and grip the hole and the cross expands the tail in four equal portions beyond the hole diameter providing positive grip. To be honest, just hammering the end of the rivet axially to both upset and produce an increased diameter tail would be better than the pointed punch. While you see rivets that are formed with a central hole on brake shoes etc, they are usually formed by spin riveting. In aircraft this hammering is normally done by an air hammer with a dome snap set against the rivet head and a square steel "reaction" block held against the tail to form it. .
I'm not sure if I have explained this very well or am in fact trying to "teach granny", if so, I apologize. I see nothing wrong with the original method used although it will require a fair bit of axial force on 6mm steel to form correctly. We would have used something like this:
http://www.tooled-up.com/Product.asp?PID '888
With a well chosen hole diameter and correct length rivet tail the single operation should take no more than a few seconds to complete and will hold very securely indeed. In short, pop the plate on; a quick "tap" on the end to swell the rivet slightly and grip the hole followed by the "set" to ensure tight contact and then some smart axial blows to form the tail - job done. If you want it to look posh the last axial blows could be with the use of a dome snap but as I have said with hard rivet material that can be problematic cold.
Regards
Keith
Keith This has been very helpful and saved a lot possible "hit and miss" if you excuse the pun. I wonder if the cross punch has a name so as to be purchased, or is it back to the "X" of the letter stamp set? Bob
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Any ordinairy chissel can produce a cross. Dirk
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Ugh sry, chisel, it is.
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Bob, you have got me there as we used to make our own rivet sets and the square patern is not one we used. If you are going to do a lot of them then I might be tempted to finish the rivet with a "waffle set" have a look here:
http://www.mikes-afordable.com/miva/merchant.mvc?Screen=PROD&Product_Code=RA1011&Category_Code 98
It looks professional and does the same job as a cross. It is also less sensitive to getting the cross centred if it has to "look right". For an odd one or two I would be tempted to set the rivet with a flat set, press punch or hammer face and finish with a narrow blade set; not a chisel edge which will cut the rivet but a square edged narrow blade about 1mm thick. A small chisel could be ground but don't use a sharp one. A simple jig to locate the blade on rivet centre could be knocked up if you have a lot to do and are using unskilled labour. The advantage of a proper rivet set (or snap) would be that the cross would be at the bottom of a circular recess to centre the set correctly. Very difficult to manufacture I would think. The other issue with these special rivet sets is that they are not cheap.
Sorry Bob I will look out my old training notes and see if a cross head set is mentioned or properly named. Problem these days is that with welding so easy rivetting has become quite specialist and centred on the aircraft industry; they use much softer rivets and either dome snap head type or a flat faced bucking bar to upset the rivet tail.
Regards
Keith
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Sorry Bob, forgot to say I don't see why your idea of a large X or a + if you can find one from a letter stamp set wouldn't work well and would be easier to locate with a simple jig.
Keith
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Emimec wrote:

They found an old Philips screwdriver and ground it flat. :-)

Centerbore and drive a centerpunch (or something looking the like) in the hole. That works really good.
Nick
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wrote:

My contribution to the fray... For pins on pinned-root steam turbine blades, we sometimes have pins that are counter bored to within 1-1.5mm of the outside and a couple of mm deep. the holes can be chamfered slightly and then the pins upset with a truncated cone type punch. Looks very neat.
Normally they just use a centre punch and put three healthy craters on the surrounding steel near the join to upset it, but those pins are not subject to any axial forces.
One other thought is that with the cross pein, the pins could be heated with an OA torch if the back part was a bit delicate for enthusiastic thumping.
Mark Rand RTFM
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An interesting point Mark, I've seen the hollow pins in many turbine engines and they do look very neat indeed.
I had, quite incorrectly maybe, assumed from the picture that the columns might be under a little axial load particularly one that pushes the plate off the column and the plate to column fixing needed to be rigid. Also, I had assumed from what Bob said that as a "production" job he would want to keep the operations to a minimum but on reflection both assumptions might be incorrect.
As Bob says that the columns are already reduced in diameter at the end then another operation to drill them to produce a hollow end might not be an issue. As you rightly say they can then be upset with a simple truncated cone to stop the plate falling off. My concerns with this and the three centre pop method would be the amount of axial load that they could take and the affect of constant reversal of load which would gradually loosen the fixing. The one other concern would be the setting of the hollow rivet as it would be to fill the hole in the plate and allow no movement between plate and column. My experience with hollow rivets suggests that many eventually work loose and spin thus providing some minimal clearance between rivet and hole which might not be desirable in some situations. If none of those are potential issues in Bob's application then it could be an excellent solution to drill the end of the column when reducing in diameter and set with a simple truncated cone on assembly.
I suppose if it is a really "low load" situation where the plate doesn't have to be firmly located on the column then one of those awful "star" type attachment washers that keep falling off anything cheap with wheels on might do the job adequately. Cut a small groove where the column comes through the plate + washer thickness of course and they will never come off. However, the plate to column fixing will never be completely rigid but no doubt Bob will know if that is an issue.
Good question Bob, certainly took me back to "better" times.
Regards
Keith
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The assembly in the pictures has to be firmly fixed, must not fall apart of have any movement. There is no real load on it, it is a support for the central screw and the plate the screw is treaded to. It allows the plate to be raised and lowered by turning the screw. The supports are threaded 8mm into brass flat
It is a production job, batches of 100, so oxy whatnot is out of the question,(unless its cold out !!).
Today I tried the counterbore idea, would need playing with to get sizes right, and a proper punch in the fly press instead of a ball bearing and a hammer. However, result was neat on the first try, held fast, but did allow support to rotate, not that this is a major problem. Continued experiment will know doubt give an ideal counterbore size/depth etc. Thanks for the interesting and helpful replies. Bob
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