Strange Chainring Bolt

[MaccyDG]

It's my first time posting on this forum - hi!

I was wondering if anyone could help me out in looking for a pretty odd type of chainring bolt, please? I've searched the net rather a lot, and I can't find anything that looks up to the job. I've attached a photo of the bolt (sorry it's not that clear, but at least it gives you an idea of what I'm talking about). The unthreaded section is 10mm long, and the bolt shaft is 9mm in diameter along that section. The threaded section is 6 or 6.5mm long, depending on where I measure it. The shaft in this section is 7mm in dia.

The bolt goes through a chainring guard, spider, washer, large chainring, washer, small chainring. There is no inner or outer - it just screws into the thread in the smaller chainring.

The allen profile on one of the bolts is almost sheared out, and I want to replace it before it gets rusted in place and I can't get it out again!

Has anyone seen this before, and do you know what it's called?

Better still, if you know where I can get hold of them, that would be great. Preferably in the UK, but postage shouldn't be too dear on something that small, so I don't mind buying from somewhere a million miles away.

If you can help, I'd be very grateful!

Cheers.

Liam

[nfmisso]

It looks like a standard shoulder bolt.

Take it a industrial hardware supplier to try to match. In the USA, a company like Fastenal, McMaster, or Ried.

[trevgbb]

you don't say what make/model, but check out the cycle mfg. website, they may have a customer service dept. who can help you.
or try your lbs., if you have an old style one, they tend to keep odd parts around.

[MaccyDG]

Thanks for your replies, both - pretty helpful. I've tried my LBS, but I'll look at shoulder bolts, and I hadn't even thought of contacting the bike manufacturer - not sure why I didn't think of that!