Build your own fin -"3D printable single fin base"

Hi Hans-

I put one of Chippy’s hockey sticks as a ghost image into the last dev release of Finfoil about a week ago. Looking forward to the STL capable version, thanks for all the programming effort and for sharing it! Let me know if you need some help beta-testing.


Good news, Hans. I’ve been waiting years for this export facility. Now I gotta cut some gears for my CNC so I can do fine tolerance work.

If you want to minimse the cost and 3D print just one fin base this design might be suitable. You could swap fins in and out of it as required.

No CAD model yet (will do that next week). Just build your fins with the appropriately shaped tab to drop in, push forward up against the slight undercut at the front and tighten up the grub screw at the back to secure the fin.


Is that an adapter for using other fins in an FU box RDM?

I like the idea of an all-around base adapter for use in FU boxes.

More innovation**…**

The idea for the hand sketch above is if you want to make fins that you can swap in and out of a standard fin box (FU) and only have to 3D print one fin base. Cheaper than 3D printing a fin base for each fin and permanently glueing/fibreglassing them together as for all the previous designs above (apart from the FCS and Futures design of course).

Rohan, nice drafting! I admire someone who can still pencil, ink, and letter.-J

I have been fiddling with the wood+FR4 longbox fin base. I made one with 1/8" (3.2mm) and one with 1/16" (1.6mm) FR4.  The thicker one is heavy and barely deflects when bent, the thinner seem to have a nice weight and ‘twang’ to it, about 1/8" when I put my thumbs in the middle and fingers on the outsides and bent the outside down. The current tab is about 4" tall, 3 1/2" at the base, and 1 1/4" at the top with the back side being 90 degrees to the base and to the top and the leading angle is 60 degrees. The wooden base covers the lowest 7/8" of the tab. I think it would easier to incorporate the tab into a new raw fin that to retrofit, but it could still be useful for repairs if one cuts the tab down to maybe 1" tall past the base and makes a slot in the old foiled fin to accept the tab + enough resin and cloth to make the joint tight. The trick would be cutting the slot straight and keeping the fin square while the resin sets.

Thanks Jim. Would be good to see what you’ve come up with. Do you need a design done with a 1/16" slot?

Here’s the CAD to go with the sketch.

Hi Rohan, thanks. I don’t need CAD at the moment. Here’s a shot of my STL and the glue-up so far.-J

Futures design is now confirmed and available.

Great works Rohan. !

Nice! I like the fact you’re accounting for the print process and how extra material = extra $ to print. By trimming off excess, unneeded area in the base it’s lowering the print cost.

I got the FCS adapter printed in ABS. It was $35US to get it printed, and it was done the same day I sent the file. It’s in the mail and I should get it tomorrow. I’ll post pics once I have it. What a rad process. Thanks RDM and Surffoils for getting this going.

Surffoils, have you installed your Universal Box yet?


I put the left and right boxes in a shortboard and gave it away to my cousin. I didnt tell him I made them so whatever report he comes back with is totally unbiased. He is a bit of a whiner though…

Mine are costing about the same in AU dollars but in a few years Im sure 3-D printers will be in a lot of homes and it will cost pennies to print.

Rohans is the real genius at all this CAD drawing / 3-D printing.


Hey All

Just to make it easier for Rohan and so he isn’t getting massive requests on links to his designs - we have put them all in one place so you can just go in and download each template whenever you need to print off.

With Rohan designs we will just continue to add them to this link- so they are all in one place and easy to find for everyone


I put it in my favorites.

Not in a position to do anything with all this great stuff right now, but soon I hope…

Got my FCS adapter base. Printed in ABS for $35US

Fit is perfect! Great work RDM. The FCS tabs fit snuggly in the adapter. I tried multiple fins and they all worked well. Some aftermarket fins were a bit tighter, but the FCS molded fins were perfect.

I put the adapter into numerous fin boxes. It was a REALLY tight fit, but it would go. I think with a light sanding on both sides it would be much easier to install and remove, but I wanted to test it in it’s as-printed state to make sure it was workable.

I need to install the grub screws and a pin, but as printed, it works perfectly.

The work you guys are doing is exciting. Thanks. I only ride shortboards, so although I probably won’t be needing a single fin adapter, I think it’s cool.

Any interest in designing an adapter for FCS fins to fit in Futures boxes? I saw that a company here in CA that’s doing it, but they want too much for the adapters, IMO. I’ve thought about this a lot and I think if you had a small screw into the bottom of the tab and a slot in the base of the adapter, you could still get fore/aft adjustment (you can’t with the way the CA company designed theirs). The only problem would be that you’d have to drill small pilot holes in the bottom of your FCS tabs, which many people might not want to do. The other option would be to just make a really snug fit, like LokBox did with their Grip-its adapters. 

Here’s the F3 adapter sitting in a Futures box :


Single fins work on shortboards too.  :-)

Great stuff here!

Curious if that adapter addresses the fact that Futures have cant built into the fin base while FCS has cant built into the boxes?

Bud, it looks like those adapters are from Surfinz F3 system, their box is built to account for the cant differences between fins. Wouldn’t be too hard to make an adapter with pre-set cants though.

Check out the images in this thread for more clarification on how those adapters work:


Also, check out the Universal Fin System thread, some 3D printed boxes in there that will accept FCS, FCS2 and Futures:

Thanks for the feedback lawless. It looks like you are the first one to print any of the designs from this thread. It’s good to hear that it’s fitment is slightly tight in the box as it’s much easier giving it a light sanding than having it slightly loose and needing to add material on.