Forming round heads on small steel rivets.

Is there a special technique for forming the round-head on small steel rivets. I have tried by attempting to peen over the rivet but have not met with the success I would like, especially when the rivets are in close proximity to one-another; maybe it's a matter of technique. Any advice would be appreciated.

last time I used any round head rivets, I made use of some rivet punches, one to protect the pre-formed head and one to form the cut end after initial peening over.

Hi Ken , There is a tool called a rivet snap ,various sizes. It looks like an oval punch with a semi circular dome hole and a drilled hole beside it to match the size of rivet .Have a set of them . Maurice.

Hi again Ken google rivet snap , lots of info.Maurice

They are about £7.00 each from RDG tools and other similar suppliers:

Ideally you want two of those snaps. One goes into the bench vice so the factory head of the rivit sits in the half round recess.

You then place your work pieces onto the rivit and "Set" them using the plain hole in a second snap, this will make sure the work pieces are pushed close together and that they seat right against the factory rivit head.

Depending on rivit size you now place the rounded hole of the second snap onto the rivit shank and hammer it down, larger rivits may benifit from some hammer work first.

Allow approx 1.5 x diameter of rivit protruding to form the head

Personally I prefer separate round snaps and sets, if you are not carful with the oval ones they can mark the surface if not held perfectly perpendicular to the work. The set can easily be made by drilling a hole in a bit of rod, does not really even have to be hardened.

Edited By JasonB on 29/07/2016 10:50:50

Are your rivets annealed ? Some steel rivets have worked hardened in manufacture making it a bit harder to set them (especially smaller ones). Also try to set the rivet with minimum number of hits - again work hardening. They say mild steel doesn't harden - I agree to differ. If all else failed, could you use copper ?
BobH

"They" haven't done much sheet metal shaping or panel beating then have they.

I have used that sort of snap at work - use a decent sized hammer and not lots of blows. The protruding length of the rivet needs to be correct for the shape of the snap. One underneath for the head and another to hit with the hammer as Jason suggests. I thought that rivets were usually annealed.

I still have an engineers hammer. It's a good deal heavier than a typical wood working type and has a ball end as well.

John

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Thanks for all the quick responses to my request.;lots of helpful info. I am riveting the tender beams on a model GWR loco & want the round heads on the reverse side too.Have previously riveted flush on the back of a 'Tich' I built & so have no experience of forming the round heads on the other side. Will try Jason's suggestion re: Home-made snaps because of the close proximity of the rivets in clusters-will report back after a few practice runs.

Ken

When things get a bit tight you have to resort to modifying the snaps, as you can see some of these have been ground down so they can fit up close to an edge

Thanks Jason - the advice & pics. are really helpful.

I made my own snaps using a ball nose milling cutter in some silver steel as the space around the rivet was quite tight.

If possible, use the pre-formed head on the outside so if the heads you are making aren't perfect it doesn't show up so much.

Neil

I would echo previous comments about new supply not being soft iron rivets.

I always add a sprinkling of fine brass file swarf onto the rivet snap that the preformed head sits in, before belting the other end.

Cheers,

Julian

Thanks to you all for your helpful advice, tips & comments - they've really been most helpful in pointing me in the right direction to success. The advice from Julian re: the use of fine brass filings works in raising the snap sufficiently to avoid marking the work - most grateful to you all!

Ken

Hello Ken, I think it was the late W.J.Hughes who recommended using three hollow punches to form rivet heads.

The sketch shows their proportions. They limit random buckling of the shank and offset heads.

Thanks for the detailed drawings John. I have made up some 'sets' as per previous suggestions in the thread so far, & have met with very good success compared to my previous attempts. Would like to make up a set like you suggest but how could I achieve the dimensions attained, particularly in diagram 2, in the home workshop?

Regards

Ken

Never done it myself but . A ball peen hammer was commonly used to preform the rivet head , you hit the edges of the protruding shank with the hammer and then finish it off with the snap.

Hello Ken, I use D bits to form the cavities. Machine the taper on and hand file the radius on the second punch's D bit. For the third one hand file that as well if you do not have a ball turning tool.

One other thing - machine say a 5 deg. chamfer on the face of the punch leaving say a 0.020" land around the opening. This will save marking your workpiece if the punch is not perfectly plumb.

Best wishes, John