Interesting thread with Deadshaper.
http://www.swaylocks.com/forums/does-futures-make-different-ant-tilt-angles-their-fins
Hat’s off to the designer, CAD guy, and the people providing feedback!
PM’s on the way. -J
Looking good.
I love watching a new product being engineered.
That last shot looks great.
I would leave the bottom of the box completely flat though.
At least the center box.
As the router will only cut it flat.
Those flanges will not press through the stringer and box will not sit flush.
Carry on.
Don’t know the exact dimensions, but I’m guessing route out an extra 1/16" deep, problem solved. Filled with resin when you install.
Although I don’t see any harm from leaving the bottom flat, either. Or sanding it flat before install?
For quads it won’t matter anyhoo.
Great thread!
Another thought…
Awhile back Wood Surfboard Supply offered these…
You could build a wood fin around the tab (leave a slot)
But they discontinued it, because it was too expensive to make, and brittle so it broke off easily.
Could you and your computer friend come up with a 3-D printed version? And maybe same for thruster / quad fins? 'Cause there are a whole lot of people who would love to make their own fins, but the tabs are the hardest part. Would be cool if you could.
You mean something like this Huck? What are your preferred dimensions for what I’ve shown in the drawing and the thickness of the “blade”? I know what the rest of the dimensions need to be as I have a few fins I can measure up.
Honestly mate; There aren’t that many of the bros laying awake at night worrying about a universal fin system. When you get it figured out though, I’m sure you’ll make a boat load of $$$$$$$$.
Wow RDM, that’s it! Any thickness of tab will work, because you build the fin around the tab, the critical factor is at what thickness do you perceive that it would be strong enough to resist snapping off under normal use? Since you know your materials best, it would be your call. thanks!
I think the blade thickness should be up around the 6mm mark. This makes for a thicker fin, but if we are using wood shells that’s OK I think.
I really like thick fins also, so I don’t see the final fin thickness as being as being a problem if it ends up at say a minimum 16mm if we use a 6mm thick blade - I’m sure not everyone will agree though.
What was the thickness of the blade on the ones in your image? What about the rest of the dimensions I have shown? Are they suitable?
great stuff , Brett and Rohan !!
if it saves me having to cut out the two frcs tabs when I send fins , I’m ALL for it , guys !
Can you put them in the next board[s] you guys make , please ?
cheers
ben
IIRC the tab was about 5mm. 6mm would be fine. The rest I’ll trust you on, not being fluent in metric, and not having a fin handy at the moment. Plus, I am thinking single fin boxes are pretty universal, no? As long as the base fits securely in the box, the fin can be built any size. The one shown was designed to be cut down if need be, according to the rake of the fin. I like that yours is already raked.
OK. I’ll measure up a few of my single fin templates and try to design the blade and locate it on the base in a manner that suits most designs. As you’ve said, it can always be cut down by hand if need be anyway.
The printers charge by the volume of material used so reducing the volume will make it economical.
Even trellis the base like a Futures fin, one of these could be expensive unless it’s thinned out.
That makes sense
Something like this? Actually a hexagon/honeycomb pattern is the most efficient use of material for the strength I believe.
I was thinking more like this, using triangulation to keep the strength.
Not sure how big the triangles would be but around 20mm on the tab. Too big and its weak, too small and its heavy.
The triangulation you have shown is good for beams in compression/tension with the load directed along the same plane as the triangulation.
But not so much for the tab in this example, as the applied load (sideways force in this case) is perpendicular to the triangulation. So the benefit you think you will get really isn’t there. The trianglation shown in your image is better suited to the fin base itself (as in the Futures fin base example) rather than the tab.
I do have something else in mind though.
The fins not really wide enough to put in any lateral strength how about a series of vertical beams and triangulate in between them ? Or use a hexagon as you’ve said ?
Something like this ?
I’m thinking maybe a smaller hexagon pattern on each side and which doesn’t run the whole way through. I need to do a few sketches and calculations first though.
Lots of little holes can sometimes do the job of a few big ones.
So an out of synch pattern on each side ? Interesting !
How about making these plastic frames in two thinner sections. You laminate them on either side of a central piece of wood, maybe ply for the strength.
And then build up over the frames on the exterior ?
You get the whole length strength from the inner core, the reduction in weight from the frames and have the perfect shaped base. Looking from the end you’d see this…
Whatever you guys decide on the base that goes in the slot should be fine. The tab that goes in the fin should be designed so it can be glued in without voids or air pockets. To minimize material cut it down in size, maybe add some vertical grooves, but no holes or voids. Just my thoughts off the top of my head.