Size of rivets to use

[Miker]

I've been trying to rivet a mast tang for a solid vang onto the mast. The rivets supplied are 6.4mm by 19mm for a mast thickness of 2.2mm and a tang of less than 3mm. I've had three attempts using a lazy tong rivetter and on each occasion the mandrel burst before the rivet was tight. The rivet goes into a recess on the tang, and to overcome this I put a nut between the rivet and rivetter. The job is becoming a nightmare with the hole in the mast and tang becoming bigger after having to drill out the loose rivet each time.
I've Emailed the supplier ZSpars but would welcome an independent opinion on whether the rivets the rivets are too long. All I can find on the internet is a recommendation that rivets should be twice the length of the material to be rivetted, not nearly four times.

 

[Freebee]

If its the shank of the rivet that 19 mm long and you are trying to tighten down onto a combined thickness of 5.2 then the head of the mandrel has to clench up 14 mm before it can tighten on the materials, this does seem to be way to long.

No wonder the mandral snaps first. To prove the point can you get hold of some scrap plate of similar thickness and try to rivet it with and without your nut adaptor, if it wont work on this test piece what chance do have on the real thing?

 

[mikebees]

Miker,
Screwfix supply 6.35 X 12.7mm Monel rivets at 78p each. These could solve your problem.
Mike

 

[mikebees]

Sorrry, for Screwfix read Sea-Screw!

 

[Miker]

Thanks. Since my post I found another internet site, the Chicago Rivet and Machine Co, which suggested that the length of the clench should be less than the material thickness. I shall have to ring ZSpars as it seems to me that 5mm by 10 mm rivets would be better than the ones they supplied despite my initial query with them.

 

[Miker]

End of story, I hope. I spoke to ZSpars who are sending me smaller 1/2 inch rivets and a new mast tang base which had got a bit chewed up with drilling out the oversize rivets.