Surfboard Replacement Fin

thingiverse

Hey everyone, I'm excited to share this design for a replacement fin for soft boards that I came up with. After searching online for a similar item in STL format but failing to find anything close, I decided to take on the challenge and create my own. This basic push-in fin is secured by a threaded 30mm location pin retainer and a 36mm long x 30mm wide head screw, making it an ideal replacement option for cheaper softboards, surf boards, and body boards. You can find similar items on eBay for about $30 Australian, but I'm happy to share this design with the community instead. This fin design is based on the canoe fin by JANMES12, which you can find on Thingiverse here: https://www.thingiverse.com/thing:964373. I chose this design because it's very sturdy at 13mm thick and practical for DIY home 3D printing. To make this design more robust, I added a wider load-spreading flange and two push-in 30mm threaded locating pins, which are about 93mm apart on my soft body board and surf board. I also created two options for fin heights: ~50mm and ~90mm, so you can choose the one that suits your needs. When printing this design, I recommend using at least 50% fill for the fins and 100% fill for the retaining screws. The screw is 35mm long x 30mm wide head, with an external size of 7mm thread for the bolt shaft and a nut receiver side of 8.5mm. Mounting the pin and screw requires a total board thickness clearance of ~60mm to ~42mm. If you need a smaller gap for a smaller board thickness, simply cut the screws down by 5mm and retry. I printed this design using Cura to produce the GCode, with an upright position and "everywhere" or "Touching Base Plate" support option. While this works well, it does leave a support mesh inside the internal female thread that needs to be removed or poked out on completion. For more detailed information and photos, please see my post printing images. I'm always learning and welcome any good constructive feedback or links to other similar items. Thanks for reading!