View Full Version : Stock Fin part replacement question

7th August 2007, 08:58 PM
HI I have a 2001 Formula 175, that has the stock 65cm fin. The problem I am having is that the back bolt hole on the fin, has some stripped threads (not the bolt, but the female recieving end that is in the fin is stripped). The problem is 2 fold. I have tried to undo the screw on the side of the fin, and it won't turn. Also, I don't know if I can find any replacement parts (does anyone know if you can get a part to replace the stripped theads?) Any help would be appreciated...Thanks.


7th August 2007, 09:53 PM
Hi Ken,
This is a pretty easy fix.
The screwdriver slot on the "barrel nut" (the brass part with the female 6 mm x 1.0 threads inside) is simply there to help with "aligning"
the barrel nut.
The barrel nut is not screwed into the fin.
Get a 5/16 drift punch/a small hammer and you can simply tap the barrel nut out of your fin.
Check with your local WS shop as they should have some replacement barrel nuts.
As another option, you can maybe save the existing barrel nut by re tapping it to 1/4-20 UNC threads. You will need to buy a 1/4-20 UNC tap and a new fin bolt with the 1/4-20 UNC threads, and the 1/4-20 UNC threads won't be at full strength, but it will work.
First, take a white Sharpie pen and a straight edge and mark the orientation of the screwdriver slot in your existing "stripped out" barrel nut.
Then take 5/16" (.3125) round drift punch and tap/drive the brass barrel nut out of your fin.
Get a new barrel nut from your dealer.
Apply some soap (a bar of soap here but liquid soap also works) to the new barrel nut and into the hole you are driving the barrel nut into.
This acts as a lubricant and keeps the nut from opening up the hole.
Tap the new nut back into your fin, using the screwdriver slot as a guide to align the threads back to the Sharpie line so the threads will line up with your fin bolt nicely.
If your dealer doesn't have a barrel nut, check with the distributor for North America (Trident Sports in Vancouver, BC).
Hope this helps,

8th August 2007, 12:57 AM
Hi Roger,
Thanks for your quick response. I now get what has to happen. Originally I thought that it was a two piece sort of unit, but now that i know the proper name (Barrel nut), it is a one piece unit that has a threaded hole in the middle. This should be an easy fix, and now that i have the size, i may be able to find one (i have no dealer in our town). Thanks again.


8th August 2007, 01:38 AM
Hi Ken,
If you have a micrometer or a good vernier caliper (or know where you can borrow one) it's a good idea to measure the OD of the brass barrel nut as there are a number of different sizes.
If you know what the outside diameter (OD) of the brass slug is, the inside threads will always be (for windsurfer fins anyway) either 6 mm x 1.0 mm metric or 1/4-20 UNC (Unified National Coarse threads in the US System).
If you know anyone with a broken off fin, you may be able to get the right barrel nuts out of the broken fin root.
According to the drawings I have the "cross nuts" (barrel nuts) should be 9.0 mm OD (0.3543") in diameter. This is why I recommend a 5/16" (0.312" or 7.94 mm) round drift punch. An 8mm (0.314" dia.) punch would be also good if you can find one.
Hope this helps,