Hi
i just got some Maui ultra fins & i need to know out what bolts fit in them.
UNF coarse & fine dont work, Metric dont work.
I been to 2 bolt wholesalers & 3 hardware stores no one has anything that will fit. MUF emailed me back but didnt tell me what the thread is, just hoping i dont have to wait another week for some bolts to be sent here.
Thanks,
Russ.
Hey Russ,
just make sure that the copper ferrel is pointing right up the screw hole, sometimes if they aren't square to the whole the bolt won't screw in. The bolts are the same as all fins so your old bolts should work fine.
All fin bolts are M6 I thought, sometimes when new the ferrule needs to be aligned by patience (or force 
!)
I dont bother with the supplied soft things that come with boards - especially those from Cobra! I have a large supply now of allen head a4 m6 bolts that I found on ebay, they are brilliant, easier to do up and undo.
I use the same bolt for all my fins, be they Select, JP or Maui Ultra .... No problems
The barrel nut (insert in the fin) is machined with a larger tolerance in the threads than a "normal" nut so it will easily strip if you hit something, thus saving your board..
That would be my guess as to why a specialist bolt retailer reckons they don't have something that will "fit" - cos it is kinda designed to not fit properly if that makes sense. They would have measured it and thought it non standard (which it is really!) Get a fin barrel nut and a standard M6 nut and check out the wobble on the former!
Your chance of getting M6 at larger hardware shops like Bunnings etc is just about nil as they do patio bolts etc, and if they do have it the staff would not know a bolt from a nut anyway 
Buy standard M6 - which is 6mm metric and standard pitch of 1mm (25.4tpi).
Any marine shop or proper fixings place will have bucketloads of them.
If it does not want to screw in, as others have said just rotate the barrel nut with a screwdriver, that's what the slot on the side of it is for
Also there is a chance that the M6 thread was not finished off correctly and is burred over or just to tight, I had to run an M6 tap through my latest C3 fin because the M6 screws would not go in at all.
I pretty sure you would be able to get an el-cheapo M6 tap that would do the job from most hardwares.
I was using the patience method for hours & then it became the force method, out with the hammer & punch ( i realy didnt wont to hammer new fins) but i should have heaps earlier. got the brass insert to move a bit & the bolts fit.
Thanks for the suggestions I'm going sailing today yay.
When you buy a new fin, don't they normally come with the bolts?
Its pretty annoying there are different threads for fin bolts. Why can't they just accept the metric standard? It would make life a lot easier.
I thought so but no, not even trying to screw a bolt in before they got sent, oh well all good now.
Rus - so its just the barrel nut needed aligning?
What is the go with special bolt place saying they had nothing? I'm curious
The rest of the world has realised conformity in thread sizes is a good thing, such as METRIC, yes it was hard to begin with but the ability to stock just one line of threads to service anything that requires a fastener is well worth it, pretty well only one country left that wont swallow it's pride and let go to change! PS look at where that is getting them
Yeh it was the brass insert not lined up perfect, thats
why the bolt places could'nt find anything to fit. could'nt
adjust it with a screw driver they were tight but hammer
& small punch moved them around & the m6 fitted.
I didnt ask for screws so thats probly why none were test
fitted before sending.
just used the 24 & its not that different to a normal fin.
Metric is fine for a lot of things but we have a mixture of metric and standard which gets rather confusing, metric and standard together on one vehicle?!
I really don't like metric for measuring temperature.
"PS look at where that is getting them" not sure at all what that means.
I got the MUF x- weed 24 & 28cm, that is what MUF suggested for my boards & the sailing i do.
I used the 24 with a 5.2 naish wave sail & a f2 axxiss 273
98lt yesty & for the first time using a weedy ever I spin out twice,
cause i was stomping around the back of the board, it just sailed great
everywere i wonted to go, up down wind, gybes smooth, heaps better
than me yellow caveman fins.
