Dynamo Lights

You'd sell a lot of those I reckon. What's the inside measurement where it passes under the fork?

Away from drawing now, but off the top of my head it is 55mm?

Maybe it's because my fork is the largest thing in the world but I think I calculated that I'd need 70mm to get right through and then enable it to be bolted on without it hitting the fork. If there's a chance you could make it longer, I'd almost certainly like one too.

Otherwise kinesis does forks with all bells and whistles (TA, tapered steerer, flat mount, mudguards mounts) and a front facing hole too. Eg the ATR fork.

Looks brill.

Again, interested in one of these for Isen summer duties without guards.

I'll buy one

Could the hive mind wave verniers at the depth of their fork crowns, and I can make sure it extends enough for most people?

Could the hive mind wave verniers

Mine was done with my daughters pink Disney Princess ruler but 70mm is the magic number that I'd need :)

Want.

There will be a list soon ;)

What do you want measured? From the back of the fork to the front at the crown, ie. front of brake hole to back of brake hole? For people without brake holes though, I presume? :)

Put me down for one. Could actually use it sticking forwards if you need a light extension under cables of canti/V brakes too. I would think 70mm would be minimum for either use, a tiny bit longer wouldn’t hurt.

May look into lazer etching penises onto the prototypes.....

Would those penises be stress risers?

On that note...

@mdcc_tester or anyone else who knows anything about FEA. I've used fusions in programme testing facility, and all seems fine with 5n downward force on the bolt holes out front. I placed a constraint across the face of the bracket that will be in contact with fork. Is this sufficient, or should I model a face to represent the fork, and then bolt the bracket to that? Also, have I done anything stupid here? Light weighs ~70g.

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newb FEA question:
Isnt 5nm a 5 newton force 1 meter out so since the thing is ~5cm long it is actually (100/5=) x20 as much at the bolt holes.

So the test show the effect of a (5 x 20 = 100 newtons =) ~10kg light mounted :)

Not sure about this...

sickfadez......bang on for you....

Sorry, i meant 5n, not nm.

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Ahh ok sorry

...half remembered facts are the best facts

I placed a constraint across the face of the bracket that will be in contact with fork. Is this sufficient, or should I model a face to represent the fork, and then bolt the bracket to that?

I think I'd do the latter, because the bolt head contact is where the load actually gets transmitted. Constraining the interface with the fork crown is more like a glue joint. You don't actually have to model the bolt, just create a spot face on the bracket the size of the bolt head and apply a load consistent with the bolt tension.

Will do. Cheers Jorj.

Tonight i will travel to the future and print a prototype.

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You got a 3d printer?!?

Will do

Now you've made me check that you can simulate the friction between the fork crown and the bracket, because without it the bracket will just fall off as soon as you apply a load, or it will rest on the bolt shank which is not what actually happens in real life.

And can you? Don't make me check too, I'll only check it wrong ;)

It's a wild Friday night round here...

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And can you?

Yes, although I haven't actually checked to make sure that including friction in contacts actually stops a static stress analysis from throwing up an "not constrained" error.