Fin Screw Insert tubes - What is best to use?

[onein5]

Hi There, Thanks in advance for considering a question I might have been able to answer myself if I had trawled the forum, apologies if so!

I want to retrofit a skimboard with some standard Twin Tip fins at the back (I know sacrilege etc.).

I figure I can just epoxy in some rust proof metal tube through the board - that matches closely the M5 diameter of the standard fin bolts, and Bob’s your uncle – question is what material should I be look for to avoid rust, and what should I be searching on Google or eBay? Metal tubes is a bit generic!!!

Am I better off getting a length and hacksawing it down? Or should I get a pre-cut length that’s as close to the thickness of the skim as poss?

Thanks again!

[BWD]

No metal.
Mark where you want the fin holes to be.
Drill through the board with an oversize bit, 12mm or 15mm would be good.
Tape the bottom of the holes with duct tape.
Fill the holes with thickened epoxy and let it cure.
Mark your exact fin hole locations.
Drill them with a small pilot bit, 2-3mm.
Go back and enlarge the holes with a 5mm bit, be careful to keep the alignment correct.
Screw the fins on!

PS: use an oversized fender washer for the screws if you want it to be stronger.

[onein5]

Of course! Nice one - Thanks so much.

[zob]

Process like BWD described it, is most common.
I go directly with 5 mm woodboring drill bit (has a center guiding bit, however with risk of misallignment stil there).

Just make sure, to have both fins inline as possible to avoid drag (rather than trying to align them with centerline).

[onein5]

Thanks Zob, I was thinking if a wood bit would be the best and was about to ask. Excellent.

[zob]

Bits get worn out fast drilling epoxy. And wood bit needs more precise sharpening, not to loose the center. So take this in consideration