mx5alan wrote:great finish on the new fins...
is the hole spacing also custom or the kiteboard standard as on regular boards ?
and will 4mm screws be thick enough for strength and support through the board or are you using inserts for more strength?
The standard F-One fins I am putting on my board are 3/16BSW thread with the standard kiteboard hole spacing.
Custom about 72mm centre to centre. I went with M4 to try get the profile as thin as possible but then you are also dictated how thin you can go by the Ti plate size and because the Ti is expensive you want to get that as close as possible. A standard hole spacing on something this would just not work you would not be able to torque down the fin to the board and might end up with the tips of the fin slightly raised.
Another thing you look at is failure at high speed you don't want super strong M6 bolts holding the fin down because if hit a rock or debris at high speed you would rather want the fin to break away from the board and not take the tail with it, you would want the fins to shear away before it destroys the board.
A few guys are using M4 bolts. To torque it down real good I'm going to use some cup washer to spread loads and I'm using some decent quality high grade Aluminum PRO-BOLTS .
jrobson wrote:Just curious but how much did these set you back? It looks like either a lot of manual work or a lot of contouring, high on machine time even on a 5 axis. If the smaller screws give you trouble it would work if you went with 4 per fin instead of 2.
mx5alan wrote: Only problems could be something floating in the water, something left buried in the sand which gets uncovered by the movement of the water or have the fins worn down by the sand - a good reason to use SS ot Ti.
Would need to find out if the new official WSSRC ruling on minimum water depth also applies to all the GPS runs ? if so - running a ground is not a major issue.
You try getting 3/16BSW aluminum bolts, or any kind of BSW bolts - Total Nightmare... ended up buying replacement set of F-One fin bolts because they use a non standard fin thread.
JMF wrote:mx5alan wrote: Only problems could be something floating in the water, something left buried in the sand which gets uncovered by the movement of the water or have the fins worn down by the sand - a good reason to use SS ot Ti.
You mean Ti and not SS ?
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