What is this part called?

[Redlight]

Is there a technical term for the nut and bolt (usually) that goes through the hole in the fork crown to hold items such as mudguards and lights in place? And are they always the same length and diameter?

(In other words, do I just need to pop into a hardware shop and buy a XXmm nut and bolt, or do I need something bike-specific?)

[Jurek]

Is there a technical term for the nut and bolt (usually) that goes through the hole in the fork crown to hold items such as mudguards and lights in place? And are they always the same length and diameter?

(In other words, do I just need to pop into a hardware shop and buy a XXmm nut and bolt, or do I need something bike-specific?)

SJS problem solvers are probably your friend here
https://www.sjscycles.co.uk/brakes/problem-solvers-sheldon-fender-nuts-10-32-mm-per-pair/

[grams]

If your fork takes “sleeved nuts” those are bike specific.

[Mrs Pingu]

Is there a technical term for the nut and bolt (usually) that goes through the hole in the fork crown to hold items such as mudguards and lights in place? And are they always the same length and diameter?

(In other words, do I just need to pop into a hardware shop and buy a XXmm nut and bolt, or do I need something bike-specific?)

SJS problem solvers are probably your friend here
https://www.sjscycles.co.uk/brakes/problem-solvers-sheldon-fender-nuts-10-32-mm-per-pair/

This..
They are not always the same length and diameter. I think I bought a selection last time...

[james]

As mentioned, some forks (I think all modern forks designed for caliper brakes) need the special nuts and bolts mentioned above. But many forks just need a standard M5 or M6 nut/bolt/washer. A photo of the fork crown might help.

[yoav]

If it’s to take a brake calliper then a bolt with a recessed nut is what’s needed, as the hole in the back of the crown is bigger than the hole in the front. If it is just to hold a light or mudguard then standard M5 bolt of the correct length is better and a standard locknut, with a washer against the back of the fork. This is because the slot in the tab of the mudguard that attaches it to the back of the fork crown is not usually wide enough to take a recessed nut without widening it so a standard nut is better, and a locknut even better.

[jsabine]

Is this a fork crown that's also got to mount caliper brakes (the fender nuts linked above are designed to replace the sleeve nuts supplied with the calipers), or have you got discs/cantis/V-brakes so the hole is just a hole?

I've probably got something appropriate in that case - I've bought the pack of a hundred so you don't have to ...

[Mrs Pingu]

You may (or not) find my post from last year useful, or not. I also used a solution cheaper than the Sheldon nuts which is why I bought one than one size, sensibly in my case.
https://yacf.co.uk/forum/index.php?topic=115981.msg2553627#msg2553627
https://www.sjscycles.co.uk/brakes/9-gilles-berthoud-brake-spindle-screw-for-mudguards/

[Redlight]

Is this a fork crown that's also got to mount caliper brakes (the fender nuts linked above are designed to replace the sleeve nuts supplied with the calipers), or have you got discs/cantis/V-brakes so the hole is just a hole?

I've probably got something appropriate in that case - I've bought the pack of a hundred so you don't have to ...

Just a hole. It's for a Dawes Galaxy with cantilever brakes, so doesn't need to hold the brakes in place. I'll send you a photo by SMS, in case you do have what's needed - we're overdue a coffee, in any case 

[fruitcake]

Any nut and bolt of the right diameter will be fine. Just needs to fit through the hole.