How much rivet do I need sticking out to form a round head?

A bit of googling suggests 1.5x the rivet diameter but I’m repairing an expensive and fairly safety critical bit of kit and wanted some reassurance!

Figured it’s the kind of thing someone on here would know.

Thanks.

When I did my apprenticeship many moons ago we did some riveting as part of the syllabus, 1.5xD was what we used.
My toolbox is still going strong nearly 30 years later 🙂

I haven’t done any for thirty five years but 1.5 sounds right. I assume you’ve got the appropriate tools for forming a nice dome, and some way of heating the rivets before you put them in so they end up in tension when they cool. The heating isn’t essential if heat will damage the components.

There must be a YouTube of someone doing it, this is 2017.

Might be worth sticking a more detailed post over on the MIG welding forum.
Lots of knowledgeable folks over there. If it’s truly safety critical they may have some useful input.

The forum is also an absolute joy to use.

Especially compared to here!

an expensive and fairly safety critical bit of kit

sounds like an ideal candidate for a ‘I asked a bloke on the internet and he said it would be fine’ bodge 😉

Machinerys Handbook

Start on page 1729 here

http://allaboutmetallurgy.com/wp/wp-content/uploads/2016/12/Machinery_s_Handbook_29th_Edition.pdf

Safety and failure info is there .

Handy as a pdf – I have a couple of physical copies but the pdf is searchable.

Further to my note – earlier editions of Machinerys Handbook have more practical info for rivets.
I am looking in the 9th edition from 1937:

Length and proportions of Rivets
In order to form the head and fill the clearance space in the rivet hole,
the rivet should have a length in excess of the thickness of the plate equal about three-fourths the diameter for countersunk head , and from
1.3 to 1.7 times the diameter for ordinary riveting.
See table rivet lenghths for forming round or countersunk.
( table starts at 1/2″ )

so 1.5 is a good guide as stated by other posters.

Well I will rise to the bait if no one else will.
What are you repairing?
You cant just say ‘expensive and fairly safety critical’ and not tell us.
Or perhaps we should just guess?
Are you building the second Aircraft carrier? 😆

Are you building the second Aircraft carrier?

Nah, it’s the pressure-hull for HMS Dreadnaught

You cant just say ‘expensive and fairly safety critical’ and not tell us.

I was being coy and waiting for someone to ask me.

I’m adding a second rivet to the head of one of these to stop it wobbling in the shaft:

Wouldn’t a bolt with a nyloc nut/spring washer be as good/better (if you go for a high tensile bolt)?

No rush OP there’s a thaw on 😉

Wouldn’t a sex bolt with some threadlock do it?

Are you 100% removing material from the head is a goid idea?

“Tried to make the joint stronger by drilling a hole in it”

Would you not be betrer off removing rivet. Epox the head back in and re rivet?

er – possibly contact manufacturer and ask what might cause head to wobble ?
has it cracked/bent done something its not supposed to?

Perhaps refrain from using it as a wood splitting axe 🙂

er – possibly contact manufacturer and ask what might cause head to wobble ?
has it cracked/bent done something its not supposed to?

It’s a well known issue which the manufacturer has refused to honour under warranty. It’s caused by a couple of quite clear manufacturing defects. Firstly,the single rivet acts as a pivot point and secondly the end of the shaft is too thin and is crushed by the pivoting movement allowing further play to develop.

I’m removing the single rivet, drilling a second hole, packing the top of the shaft with epoxy and re-riveting. We’ll see…

OK – thats clear – so as long as the rivet material is the right type then
ensuring the shaft of the rivet expands into contact with the right component.
There are notes about reaming the rivet holes for optimum strength/contact in the Machinery reference.

Thanks for all the advice folks. I’m not convinced it will work but it’s worth a go.

To the person suggesting a nut and bolt instead, I considered that but the top of the shaft gets a lot of abuse from contact with rock and I was worried about a nut quickly turning into an unusable mess.

No rush OP there’s a thaw on

🙂

Clearly, it’s up to you, OP.

However, no way[/i] I’d be messing with that. If warranty is truly not an option, then bin it and get something else.

However, no way I’d be messing with that

Likewise, your choice but…

People have been modding, messing around and making their own climbing gear for years without dying*. As long as you’ve got a bit of an understanding of the mechanics there’s no reason why not.

*mostly.

As someone who has been saved from probably serious injury by an RP2 I sypathise, but really, the best place for duff gear is the metal bin of the local recycling centre.

Done about 10 routes with this now and I’m still alive…

So did you rivet it?

Yes, 2 new rivets.