RE: Stock Fin part replacement question
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,