3D Printing 3D Design Contest - LE Sanding jig - Due Aug 22nd, 2019

dr wogz · Aug 16, 2019

Hi All,

yes, I'm skirting my responsibilities! Busy!

OK, this week-s design contest is a sanding jig. Something to help round the leading edge of fins. As some of you know, I hate seeing square fins; namely the leading edge. I find a rounded leading edge just looks more 'finished'. A square leading edge to me, just says "plank" or 'unfinished'

So, design me a tool that can be used to round / shape the leading edge of a fin. It doesn't have to be fully round, but something that will take the edge off! Design it to take some sand paper, or sanding film. Design it to be use don 1/4" ply or 1/8" balsa.. Full round, half round, 3:1 Ogive..

alexzogh · Aug 16, 2019

https://www.thingiverse.com/thing:3814319

vcp · Aug 17, 2019

Not specific to fins, just the collection of general sanding tools I did a while ago: https://www.thingiverse.com/thing:2962420

Edit: Hmmm, thinking about how I could do these in the OpenSCAD customizer...
Edit2: ... and I need to add concave straight angle versions for beveling.

dr wogz · Aug 17, 2019

alexzogh said:
https://www.thingiverse.com/thing:3814319

cant / don't see anything.

can you post it to the thread?

cwbullet · Aug 17, 2019

dr wogz said:
cant / don't see anything.

can you post it to the thread?

Me either.

manixFan · Aug 17, 2019

(I reread the first post and realized my jig doesn’t fit the requirements. It creates sharp leading edges, not rounded. But it should work for balsa if scaled down.)

Here's mine. I designed it originally for my 98mm CF Mongoose fins, which are more than a 1/4" thick. I started with 80 grit and worked up to 220. It gets the leading edge sharp enough to be dangerous. The nice thing is I can wet sand them in my utility sink in the laundry room. I've made a scaled down version for 3/32" and am going to print one for 1/8" soon. Done in Solid Edge. Super simple but very effective design.

Tony

Here you can see how blunt the bevel was even after having them sent off to beveled by machine. The original bevel was not very good:

Side view of finished bevel. It was impossible to get a good photo of the bevel edge on:

alexzogh · Aug 18, 2019

Sorry about that.

Super simple - 5mm strip of sanding paper accross the C, held by the clips. It's very small, but can be scaled for larger fins.

vcp · Aug 20, 2019

dr wogz said:
cant / don't see anything.

can you post it to the thread?

This was apparently posted to the Thingiverse twitter account 14 hours ago as of this posting:
"We are aware that images on newly uploaded Things are not displaying correctly and apologize for the inconvenience. We will update here once the issue is resolved."

dr wogz · Aug 21, 2019

alexzogh said:
Sorry about that.

Super simple - 5mm strip of sanding paper accross the C, held by the clips. It's very small, but can be scaled for larger fins.

View attachment 390846

Cool,

But I don't see how the clips hold things in place..

alexzogh · Aug 22, 2019

dr wogz said:
Cool,

But I don't see how the clips hold things in place..

A picture is worth a thousand words

dr wogz · Aug 22, 2019

Super! makes total sense now!

DaHabes · Oct 15, 2019

manixFan said:
(I reread the first post and realized my jig doesn’t fit the requirements. It creates sharp leading edges, not rounded. But it should work for balsa if scaled down.)

Here's mine. I designed it originally for my 98mm CF Mongoose fins, which are more than a 1/4" thick. I started with 80 grit and worked up to 220. It gets the leading edge sharp enough to be dangerous. The nice thing is I can wet sand them in my utility sink in the laundry room. I've made a scaled down version for 3/32" and am going to print one for 1/8" soon. Done in Solid Edge. Super simple but very effective design.

Tony
View attachment 390824 View attachment 390825
Here you can see how blunt the bevel was even after having them sent off to beveled by machine. The original bevel was not very good:View attachment 390826
Side view of finished bevel. It was impossible to get a good photo of the bevel edge on:View attachment 390827

I really like this design. What angle is used for the bevel? I'm going to spin up a parametric Openscad design template so I can create one of these for any width fin. TIA.

manixFan · Oct 16, 2019

Mike Haberer said:
I really like this design. What angle is used for the bevel? I'm going to spin up a parametric Openscad design template so I can create one of these for any width fin. TIA.

It's supposed to be 15 degrees, but for some reason it ended up being 20. It got the leading edge sharp enough that I cut myself later when I had glued the fins to the body tube. I am not joking. I used one of the big fins to cut an apple and my wife was not amused. I won't make them that sharp again, they probably would be better slightly rounded.

I will eventually duplicate it in OpenSCAD as well. Should be pretty easy to make parametric.

Tony

Jason E. J. Manaigre · Oct 16, 2019

Hi Tony, is your jig on thingyverse....cant seem to find it?

manixFan · Oct 16, 2019

Jason E. J. Manaigre said:
Hi Tony, is your jig on thingyverse....cant seem to find it?

No, the first one I made was specific the fin material for the 98mm carbon fiber Mongoose. I did make another one for a 3/32", but I really think it needs to be redone as a OpenSCAD file that is completely user configurable. I can send you the 3/32 version if that would help.

Tony

DaHabes · Oct 16, 2019

Here's a parametric Openscad routine I whipped up today for building a sanding jig like you did in Solid Works. It's not entirely issue free (if you make the overall size of the core too big or small, the subtractions may not work), but it suffices for your normal fin thicknesses. I just sent out one for 3D printing for 1/4 inch plywood fins for my next build. Should get it in about a week and will report back. Download and change the extension to .scad....

Jason E. J. Manaigre · Oct 16, 2019

manixFan said:
No, the first one I made was specific the fin material for the 98mm carbon fiber Mongoose. I did make another one for a 3/32", but I really think it needs to be redone as a OpenSCAD file that is completely user configurable. I can send you the 3/32 version if that would help.

Tony

Sure, why not. Doesnt hurt to check it out.

kalsow · Oct 17, 2019

Mike Haberer said:
Here's a parametric Openscad routine I whipped up today for building a sanding jig like you did in Solid Works. It's not entirely issue free (if you make the overall size of the core too big or small, the subtractions may not work), but it suffices for your normal fin thicknesses. I just sent out one for 3D printing for 1/4 inch plywood fins for my next build. Should get it in about a week and will report back. Download and change the extension to .scad....

When I first saw manixFan's design back in August I added doing an OpenSCAD version to my to-do list. Your posting reminded me to get on it. So here it is. As always, rename it .scad and enjoy!

P.S. generating the radiused edges was a nice little puzzle.

3D Printing 3D Design Contest - LE Sanding jig - Due Aug 22nd, 2019

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