What type and length of rivets?

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Tinpotflowers
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What type and length of rivets?

Postby Tinpotflowers » 14 Aug 2019, 12:34pm

A friend of mine was daydreaming and rode into a protruding kerb he went over the handlebar and brock his wrist.

Consequently, the SKS front mudguard was knock and become disengaged from the bracket that hold it onto the brake bolt.

I have files of and removed the rivet in the mudguard and need to re rivet the brackets.

I measure the holes I believe I need 6mm riveted but which type and length?

NB, I do have a rivet gun

Brucey
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Re: What type and length of rivets?

Postby Brucey » 14 Aug 2019, 1:13pm

that'll be a 6mm aluminium pop rivet you need then. The thing is that you may struggle to find them short enough, and if you do, you may be forced to buy dozens rather than just a few. If you are pernickety about the amount of rivet showing on the inside, you are better off taking the pin out the rivet, trimming the rivet to the exact right length, and then using a tapered punch to set it.

I have looked for solid aluminium rivets and failed to find any that were easy to buy. Maybe someone else knows better?

FWIW it is also possible to make a very satisfactory connection using a CSK M3 screw/nylock nut in stainless, using washers that are sized so that the CSK head doesn't quite pull through. To make this work, IIRC I had to buy allen key type CSK screws, which had a slightly larger head than slotted ones.

cheers
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rjb
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Re: What type and length of rivets?

Postby rjb » 14 Aug 2019, 1:51pm

A few clothes washing powder boxes come with a plastic handle held on with aluminium rivets. Careful removal yields a pair of aluminium rivets which can be recycled for other purposes. :wink:
There are likely to be other containers which use the same method.
At the last count:- Focus Variado, Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin, Raleigh 20, Falcon K2 MTB dropped bar tourer, Longstaff trike conversion on a Falcon corsa. :D

tatanab
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Re: What type and length of rivets?

Postby tatanab » 14 Aug 2019, 2:21pm

I don't bother with replacing rivets. I use screws, M4 (from memory) or whatever I have in my bit box. You will probably find small quantities in your local DIY shop. I prefer to use nyloc nuts but that is not essential.

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531colin
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Re: What type and length of rivets?

Postby 531colin » 14 Aug 2019, 2:24pm

For some time I've used M4 button flange screws..https://www.westfieldfasteners.co.uk/A2_ScrewBolt_SHBtnFlg_M4.html
I just noticed M4 mushroom head screws have about the same head thickness and diameter https://www.westfieldfasteners.co.uk/A2_ScrewBolt_SlotMush_M4.html
I never run guards close enough to the tyre that a bolt head projecting 2mm would matter...Brucey's way would project less, but I'm not sure I have the patience.

Tinpotflowers
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Joined: 31 May 2019, 7:16pm

Re: What type and length of rivets?

Postby Tinpotflowers » 14 Aug 2019, 2:31pm

Brucey wrote:that'll be a 6mm aluminium pop rivet you need then. The thing is that you may struggle to find them short enough, and if you do, you may be forced to buy dozens rather than just a few. If you are pernickety about the amount of rivet showing on the inside, you are better off taking the pin out the rivet, trimming the rivet to the exact right length, and then using a tapered punch to set it.

I have looked for solid aluminium rivets and failed to find any that were easy to buy. Maybe someone else knows better?

FWIW it is also possible to make a very satisfactory connection using a CSK M3 screw/nylock nut in stainless, using washers that are sized so that the CSK head doesn't quite pull through. To make this work, IIRC I had to buy allen key type CSK screws, which had a slightly larger head than slotted ones.

cheers


Are you suggesting this type of rivet is not suitable?

https://www.accu.co.uk/en/dome-rivets/6 ... GMEALw_wcB

I thought of using screws and lock nut , but would that be safe in that if the mudguard got knock again you wand the fitting to sheer off ?

drossall
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Re: What type and length of rivets?

Postby drossall » 14 Aug 2019, 3:09pm

I've mended many mudguards over the years with my late father's old hand-held rivet gun (really it's the plier type and not a gun at all). I've just used the standard rivets that are sold for use with such guns in DIY shops and the like. Length of rivets has never been an issue. Don't forget that they collapse slightly as part of the rivetting process, so will end up shortened. And you should have reasonable clearance anyway under the guards, to avoid stones and the like getting stuck and jamming your wheels.

Tinpotflowers
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Re: What type and length of rivets?

Postby Tinpotflowers » 14 Aug 2019, 3:29pm

Given the comments made I decided to use screws and nuts with a mudguard support bracket to strength.

20190814_144925.jpg
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tatanab
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Re: What type and length of rivets?

Postby tatanab » 14 Aug 2019, 3:44pm

Reverse the screws. The nuts go on the outside because they are the tallest, and the shallow screw head goes inside.

Tinpotflowers
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Re: What type and length of rivets?

Postby Tinpotflowers » 14 Aug 2019, 3:54pm

tatanab wrote:Reverse the screws. The nuts go on the outside because they are the tallest, and the shallow screw head goes inside.

Done even thought the srcew head were only say 2mm thinner that the nuts but point taken.

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andrew_s
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Re: What type and length of rivets?

Postby andrew_s » 14 Aug 2019, 3:55pm

tatanab wrote:Reverse the screws. The nuts go on the outside because they are the tallest, and the shallow screw head goes inside.

It can also be better to use hex headed screws, rather than allen or philips. The head is often shallower, and it's easier to remove encrusted mud from the outside of a hex head than from a socket. Slotted screw are also easy to clean, but may be difficult if the nut seizes.

JonMcD
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Re: What type and length of rivets?

Postby JonMcD » 14 Aug 2019, 4:15pm

So many ways to skin a cat! In the past I've used pop rivets with a backing washer and then used the snapped-off rivet shaft to knock out the steel head trapped in the rivet. Once that steel head is clear you can drill/file/hammer the excess rivet material to a low profile.

reohn2
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Re: What type and length of rivets?

Postby reohn2 » 14 Aug 2019, 7:22pm

531colin wrote:For some time I've used M4 button flange screws..https://www.westfieldfasteners.co.uk/A2_ScrewBolt_SHBtnFlg_M4.html
I just noticed M4 mushroom head screws have about the same head thickness and diameter https://www.westfieldfasteners.co.uk/A2_ScrewBolt_SlotMush_M4.html
I never run guards close enough to the tyre that a bolt head projecting 2mm would matter...Brucey's way would project less, but I'm not sure I have the patience.

:wink:
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TrevA
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Re: What type and length of rivets?

Postby TrevA » 14 Aug 2019, 9:49pm

I used pop rivets to fix mine. Yes, you do have to buy a box of 50 or so, but they only cost £3 for a box. They can also be used to affix a home-made flap, for the benefit of those riding behind you.

igauk
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Re: What type and length of rivets?

Postby igauk » 15 Aug 2019, 12:22am

Or do as I did when the rivets pulled through my front SKS guard and use a rear brake bridge on the front. Actually made the guard much more stable.

https://www.sjscycles.co.uk/mudguards/35mm-sks-stainless-steel-rear-mudguard-bridge-each/
Moulton TSR 30