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View Full Version : Screw length for is 144


AJ
6th March 2008, 12:39 AM
Hallo Remi + co, im the new superhappy owner of a is144, board looks awesome..
but eh, what kind of screw, or screwlength works for deep tuttle?...the normal tuttle works
with the screws that came with the board, so a little help will be appriciated...

thanx

aj

Roger
6th March 2008, 09:03 AM
Hello AJ.
What fins will you be using that have a deep Tuttle fin root.
From the specs. on the website it looks like your board was supposed to come equipped with a 52 cm (R13 Race NR 520)
Here's the specifications:
iSonic 144 W85 144 225 85 58 8.4 TBA 7.0-11.0 R13 Race NR 520 40-56 Deep Tuttle
How much bigger fins do you intend to use.
Std. Tuttle root fins are OK if the fin span is < = 58 cm.
If you go larger than 58, then a Deep Tuttle fin root would be a good idea.
The Deep Tuttle fin extends 18.00 mm (0.709") deeper into the fin box than the std.
Tuttle so you need 2 fin screws that are 15 or 20 mm shorter than the stock screws you have that fit the std. Tuttle fin root depth.
If you get the 20 mm shorter, make sure they screw completely through the brass barrel nuts.
If you get 15 mm shorter screws, make sure they do not bottom out in the clearance hole below the brass barrel nut.
Hope this helps,

AJ
6th March 2008, 09:49 AM
Hallo Roger, i have a deep tuttle tectonic 48cm which i think will be perfect for the
board..15 or 20mm less?..

thanx for your repley!!

Roger
6th March 2008, 01:56 PM
Hi AJ,
Does your Tectonics fin have barrel nuts, or is the plastic fin root simply tapped?
All the Tectonics fins I have are tapped 1/4"-20 UNC right into the plastic Dennis
uses to cast the fin root.
If your fin is tapped, then an even shorter screw with the correct threads (1/4-20-UNC or 6mm x 1.00 mm) would be needed as the treads extend right up to the top of the fin root vs 0.50" (12 mm) lower down in the root for brass cross nuts (barrel nuts).
Hope this helps,

AJ
6th March 2008, 03:40 PM
Hey Roger, yes they are...tapped, so what "exact" length will you propose, dont have
that many formula-screws to expierence with...

thanx!!!!!!!!!!!

AJ

Roger
6th March 2008, 09:08 PM
Hi AJ,
I think I would put the fin into the board and tap it very lightly with a rubber mallet to
"seat" the fin root in the box at the correct depth.
If it's at the correct depth (where the bottom of the root is flush with bottom of your board) then you need to do a little "fitting".
Try to fit your fin so the root is a "push fit" into the box and the bottom of the fin is about 1/64'-1/32" "proud" of the bottom of your board. That last 1/64"-1/32" is the "draw" that will seat your fin very tight and prevent any anomolies due to a poor fit between the fin root and the fin box.
OK, then get a small straight stick or rod (small enough to fit easily down inside the treads in your fin root.
Carefully measure from the top of the board to the bottom of the holes in the fin root.
Be sure to try a screw in the holes to see how deep the threads extend.
Be sure to allow for the flat SS washer and the rubber/plastic gasket.
The measurement from the top of the board (including the washers/seals) to the bottom of the holes in the fin root is the length you will need.
I would suggest you reduce that by around 1/4" because it's impossible to tap a hole fully to the bottom due to the lead on the tap and the drill point angle at the bottom of the hole.
Also getting a screw that extends all the way to the bottom of the holes is far too much
thread engagement. If you can get 1/2-3/4" of thread engagement, you will have all the strength that's available.
Be sure to use some soap on the fin root and on threads to make things slide together and keep the threads in top shape.
Hope this helps,

AJ
6th March 2008, 09:38 PM
thanx...you dont make it look that easy..hehe..ill try and use your guidelines..but still
cant really understand why you guys make a deep tuttle board, sell it with a tuttlefin, and
then this xtra work just to use a another fin..cant believe why it dosent come with the
correct screws.. nevermind, ill use your tips..thanx roger...

Roger
6th March 2008, 09:46 PM
Hi AJ,
I understand your frustration, but you are not using a stock Starboard fin.
Aftermarket fins mostly need to be "fitted" a bit, and since you are using a Deep Tuttle Fin root the screws need to be a different length than those used with a std. tuttle fin head.
Are you sure that the R13 Race 520 fin is a std. Tuttle head?
How did you get a Deep Tuttle Tectonics in only 48 cm span?
Maybe we need to look at this again.
Have you compared the 2 fin roots?
Is the Tectonics about 18mm longer?
Hope this helps,

AJ
7th March 2008, 03:57 AM
hello roger, yes, its abouth 18mm shorter..ill try to cut down formula screws and
try my way around it..
got the fin directly from tectonic, got it for a 134l jp slalom last winther..back then it
seemed logically to get a deep tuttle for a deep tuttle board..hahaha..no worries, ill
get it tuned...

Roger
7th March 2008, 07:53 AM
Hi AJ,
Before you go cutting off your long 6mm x 1.0 fin screws, try one in your Tectonics fin.
Unless something has changed, I'll bet that the fin root is tapped for 1/4-20 UNC threads.
You should be able to buy a 1/4-20 UNC screw/bolt the correct length and no cutting is required.
If your fin is indeed 1/4-20 UNC you will really goof up the threads by trying to screw 6mm x 1.0 screws into them.
If, on the other hand, your fin is tapped for 6mm x 1.0 metric threads, if at some point you foul up the threads, you can retap then to 1/4-20 UNC.
Hope this helps,