cutting fcs tabs

can any of you share some tips for cutting out the base tabs for fcs fins?

i cant seem to get an even cut between the two tabs. using a jigsaw with a carbide grit blade, i start in the middle and cut toward in an arc toward one tab, then fit the blade in next to that tab and cut across to the other tab. always comes out crooked and having a hard time cleaning it up…tried dremel, file, mini sanding block, etc

any good tips or unique jigs?

thanks guys!

ps i scored some 12"x12" carbon fiber test panels that are right about 1/4" that should make some pretty nice fins. i will post some pics when i get something foiled up…

Kokua is right about the wood grain.


I think these particular hardwoods, the tabs would not break off even on a full sized  thruster fin, unglassed, as long as the wood grain was oriented vertically into the tabs.  The 7 inch Koa single fin broke where I had to glue in a piece of oak for the fin screw as I broke the koa when foiling it.  I think If I did not have to do this, it would have lasted longer.  But I resurrected it.  It cleaves water again.


I never trusted the oiled hardwoods enough to leave them in the tabs after a surf. I was afraid they’d swell and never come out, so I was pulling them out and re oiling them after every surf.  It got old quick, and as I said, I never really liked how they rode, much to my dismay after the effort I expended in making them.  Tonight was the first time they saw light for years when I took them out to photograph in my board.

Here is the Balero fin in my board.  The other fins are among the first I ever made.  Walnut and white oak.


A shot of the tabs from the bottom:

Here is my first attempt at wood fcs fins nearly a decade ago.

I never trusted just the glass alone on top of the wood to be strong enough.  These stainless screws go at least 1 inch deep into the fin, probably 1 1/4"  can’t remember.  Not easy to hand drill into the fin without busting out the side. This fin suffered damage in transit to a surf on the rear tab.  I surfed it anyway in overhead waves  without it breaking, then just cut some grooves in the tabs with an angle grinder and cut off wheel, and filled them with epoxy saturated fiberglass roving, an approach I used on later fins to re enforce the tabs.  My Fcs plugs are sunk into a solid cedar block which goes to the deck, locked into the structure of the board, so I pretty much want the tabs as strong as possible too.


I no longer use the  stainless steel screws in the fins.  When I broke off the screw tab on my 9.5 inch longboard fin, I found the screws were not water tight and the  Sapele wood surrounding them turned to mud in the 8 years I’d been suring that fin.  I made some carbon fiber rods, then epoxied those in place of the screws.  Also moved the screw tab to the other side of the fin using carbon fiber. 



      Aloha ben,Look at the way the grain in the wood runs,since it runs perpedicular to the the way it would break is probably why they won't break off real easy. Aloha,Kokua

I made this fin from  a piece of kauri Wood I bought when In NZ 12 years ago, part of the buried forest  carbon dated to 40,000 years ago.


I never got the inline single twin to work properly in my shortboard.  My longboard is a different story.


The single trailer in this photo is Ipe wood/ brazilian walnut, also before I glassed it, but hard to tell.

The side fins are just plywood, and the board is my 6’8" goto shortboard(220 lbs)  made it in December 2002.

post repeated below


The unglassed Koa fin shortly after it snapped.



Still looking for the purpleheart and balero fin pics when installed…

The Red Fin was a chunk of wood I found in a bin at Cut and dried hardwoods in Solana beach.  It said Balero in it, and is incredibly dense and strong  It smelled like  burnt sugar when foiling it.  I have not been able to find any info about this wood, or what other name it might go by but have not tried recently.


I will look for a photo and upload it, or just pull out the fin and install it for a photo for you.


In the mean time.  Here is a Koa wood  Single fin that I rode a lot without glass before one hissing cutback sent me flying.  Luckily it did not shear off completely, and I rebuilt it, and glassed over it.

Just noticed the inset photo. Little bonzer like fins I made out of lacewood.  With canted tabs 


I rode them once.  Like pulling a sea anchor.


Better photos to come…

nice !


HOW did they not snap , without glass ??


Can you post up a shot of them , in the plugs , on your board , please ?



" I've been wanting to try a jig with a tablesaw, cause cutting outside the line with a jig saw then sanding down to it is almost a lesson in futility. Certainly a lesson in patience...."


  ah yes ...patience , grasshopper !


  a forgotten virtue , in this age of   " gimme,  gimmme , gimmme , I want it ...NOW !! "


  I love seeing people's homemade fins !



I’ve been wanting to try a jig with a tablesaw, cause cutting outside the line with a jig saw then sanding down to it is almost a lesson in futility. Certainly a lesson in patience, and frustration.

  The best part is when you get really close, then take a couple more swipes, then go too far and it wobbles in the box/ plug/tab.  Then you get to re hot coat it, and try again.  Oh what fun!


What is kind of key  is a fin holding jig that will not allow one to round the corners when attempting to sand/file to the line. 


These were probably my most sucessful ones.  Purple heart and Balero.  I never glassed them, just oiled them.  I did not really like the way they rode with a 7inch single fin, I went back to a double foiled 70/30 2.25" side bites that had more flex.



hi there " grasshopper " !


" i cant seem to get an even cut between the two tabs "


yes , welcome to my world!  it ain't "easy" is it [despite what some may say ...they are usually the ones who haven't MADE any !  lol , etc]


  Anyways ...


 ......It's actually reassuring for me , to know that , after making nearly  500 pairs of fins over the last  ? however many ?  years , I am not the only one who has problems getting the area between the tabs 'perfect' ...(it's one of the reasons I'd like to have had 'proboxes' on all my boards , much less fiddling / fartarsing around !  )


  Like you , I also cut them out with a jigsaw with a carborundum blade .

Therein may lie the problem . Hard to get it perfectly perpendicular , handholding it , I find ?  [....but maybe that's just me , eh ? ]

I know 'Silly' [ Paul Cannon ] typed once that he uses the much finer-bladed scroll saw , giving more control. I , however , don't have one ...yet.


  So, after cutting just OUTSIDE the line , I have to [tediously] file down to the line , to even it up . Yes , it takes TIME ! I clamp them to the kitchen bench , and carefully file away .


I hope 'ruckusman' covers this in his 'fin foiling' video ? 

It will help more to actually SEE it , rather  than just 'talking' [typing] about it !]



It's really encouraging to me ,  to see someone else making / having a go at fcs fins ... good on ya mate , keep up the good work  !


....and .... about a ride report on how they go ?


   cheers !


  ben , the fintinkerer

Uhmmmmm- myself, I’d maybe clamp the fin blanks ( before foiling) together, then use the cutoff/bevel attachment in a table saw plus a good, sharp blade - better yet, a dado blade- to cut the slots in the base and for that matter, cut the tabs to the exact width.

If you have access to a tenon-cutting jig fo a tablesaw, that’d make a very good way to get the tab widths really precise. I might do that first, so that you have an exact cut depth/tab length to work off of.

If you’re going from rectangular blanks, then I’d make the tabs symmetical with respect to said blank. Then you can foil/cut outlines easily, one the mirror image of the other. Or, clamp 'em together (or hot glue 'em lightly) back to back and do both at once.

hope that’s of use - usually I’d throw in a sketch but this forum software has issues with my browser and I’m not going to an also-ran browser just for this.






looks straight untill you put it in the board, then you can see base is a bit off…

you can see where the test panel had a bit of delamination between plys and threw off the foil a little bit too. should be able to fill and fine tune the foil pretty easily though!

good stuff wrc !


  good having you a-board !


  a belated welcome to swaylocks !


  those woods look nice , where [what country] are they from ?


  cheers !



How about a pattern bit in a router? Use either a pre-cut template or use a fin and a top bearing bit. Slow steady and shallow passes. You can also invert the jigsaw and mount it in a bench or Workmate, That way, you can handle only the fin. Drill a hole in a piece of plywood and clamp or screw the jigsaw to the underside. Clamp or screw the plywood to a bench and cut away (and file).

Actually, you could do up something similar to quite cheap. is even simpler .

hope that’s of use





Not really sure which woods you are referring to, but I’ll cover them all.

I still really don’t know where the" Balero" comes from ,  “Redheart” is indigenous to Mexico, Balero sounds Mexican, so lets go with that. I don’t think it is Paduak which is African.

The Koa is of course Hawaiian. It was salvaged from a very old home in San Francisco.


The Lacewood comes from your part of the world.  Goes by Australian Oak too.  Smells like oak when foiling.


This fin lacked drive and was squirrely until I Moved it way back.

These fins have canted tabs and were an overwhelming PITA to shape.  And of course they rode horribly, at least with a 7 inch center fin, never tried them again.

The Surfboard is made from Western Red Cedar and  probably came from British Columbia.

 Purpleheart is native to central and South America.


Ipe wood is from Brazil and is probably the toughest wood of any mentioned.  I made a 7 inch fin from it. with 6 layers of 4 oz in the middle.  Nice flex, but I’ve really steered away from the single fin side bite set up and am back to the thruster with smaller trailer as it is faster and looser.  But for powering around whitewater or stalling in the barrell, the deeper single has tremendous hold and drive.

what about a metal chop saw? It’d make a perfect cut.
I’ve never used it for this but, I know that a metal cutoff wheel on my 4" grinder SLICES through fin tabs.

try a coping saw

How about a jig that holds the fins tab side up and allows you to run a router bit with a bearing like the one used for a probox install across it, leaving a perfect 90 on the inside and outside edge of your tabs. So the base of the router would glide across the bottom of the tabs, does that make sense?

As usual, Jesus and I are thinking the same. Very smart guy, Jesus. is a router jig for making two tenons,with the appropriate top-piloted bit or collar A very simple variation on this would make two tabs, perfectly spaced and perfectly cut, perfect depth if you set your router correctly.

Whittle it (the jig) out of a piece of aluminum or plexiglass or whatever you have handy with precise measurements and your handy saber saw. And please, lose the ‘carbide grit saber saw blade’- they are really made for cutting tile, coarsely, and no more than that.

hope that’s of use>p>