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JohnCoker

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First try at using the OpenSCAD nose cone slicer. Really nice job, Bill Kalsow!

2796E920-E6C3-4859-B459-8564AC480CF4_1_105_c.jpeg
 

JohnCoker

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In case you're interested, I made a small change which allows support for an eyebolt hole in the floor:

Diff:
42a42,44
> // Radius of hole in shoulder base
> Base_Hole_Radius = 0.125;
>
392c394
<   in2  = [[ maxX, (doBase) ? 0 : (inside(maxX) - (doTab ? Tab_hGap + Tab_Thickness : 0)) ]];
---
>   in2  = [[ maxX, (doBase) ? Base_Hole_Radius : (inside(maxX) - (doTab ? Tab_hGap + Tab_Thickness : 0)) ]];
395c397
<   in3 = [ if (doBase) [ x3, 0 ]];
---
>   in3 = [ if (doBase) [ x3, Base_Hole_Radius ]];
 

cwbullet

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In case you're interested, I made a small change which allows support for an eyebolt hole in the floor:

Diff:
42a42,44
> // Radius of hole in shoulder base
> Base_Hole_Radius = 0.125;
>
392c394
<   in2  = [[ maxX, (doBase) ? 0 : (inside(maxX) - (doTab ? Tab_hGap + Tab_Thickness : 0)) ]];
---
>   in2  = [[ maxX, (doBase) ? Base_Hole_Radius : (inside(maxX) - (doTab ? Tab_hGap + Tab_Thickness : 0)) ]];
395c397
<   in3 = [ if (doBase) [ x3, 0 ]];
---
>   in3 = [ if (doBase) [ x3, Base_Hole_Radius ]];
Nice addition.
 

FjStix

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Working on an AV Bay Sled/Assembly. Will be printing it tonight.

1620417097147.png
 

FjStix

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Still working out the kinks for the full assembly.
FBCCAA6F-902A-4E21-AF82-85C7574C7339.jpeg
 

cwbullet

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Interesting design.
 

FjStix

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Interesting design.
It’s far from final. Not convinced 3D printing is the best route for such an important component. I am going to see how much yanking it can withstand next.
 

_kestrel_

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Made a quick and dirty tube cutter. Push down on the handle and rotate the tube. Nice clean cut.

tube_cut.jpg
tube_cutter1.jpg
tube_cutter2.jpg
 

Michael L

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I'm about to start the design of a taper section to screw into the the motor retainer for an Apogee Aspire. The motor retainer came from Thingiverse. It was designed for a 29mm tube but it was 4.5% too large in diameter. The taper section will (I hope) blend the retainer into the rocket. I'll design 3 fin slots into it (Aspire can be 3 or 4 fin). It has an Easy Mini and it is set up for dual deployment. The rocket sustainer is also the motor tube. Tim designed it to go high, 5,000'+, or fast, Mach 1. I'm hoping for both. The first motor will be something (as yet undecided) 60 N-s or less. The second is a G74-9W... if it survives the first flight.

The design problem that I think I'm going to have is the lack of 3D CAD skill. If the threads would have been the right size I could just "cut" them into the base of the cone shape from the original design but, as already mentioned, it's a little too large in diameter, so I have to figure out thread pitch. Maybe not, I suppose I could just make the cone base slide over the threads and epoxy the the cone to the threads (after the retainer of course)

 

Michael L

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This is on the printer right now. I'd say "guess what it is" but the odds are of getting the right answer are pretty slim :) 3 hours to go. 11 hours total. It's for a friend of mine that does woodworking.

Tilt it forward so that the flat bottom facing you is the foot. Imagine that it's finished and there are two more holes in the top. Lucky number 7. Dice. He cut a 4x4 into equal (close to) 3-1/2" cubes. This jig will be clamped to the workbench or he'll use the 4 holes in the foot and drywall screw it down. Slide the block in, center punch the holes, flip, center punch the next set of holes, flip, repeat until 1, through 7 are punched. He doesn't have a drill press so this will let him use a spade or Forstner bit to drill larger holes that he'll either put epoxy in, paint, or glue something like a different wood into. When he's done, he'll have a set of lawn dice. Apparently that's a thing. The jig will speed up the process. The big hole in the back is so he can push the block out.

 

Michael L

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I'm still trying to get the hang of how much tolerance to include in a design. On top of that, cardboard tubes are tricky to mic (bending and bumps) but I finally got the taper fitting ID figured out. Now I need to add the fin slots.

Tim says the Aspire will break Mach or go to 5,000'+ depending on which motor is used. I guess we'll find out.

I made the taper because I don't want to tape the motor in (I know it'll work. I don't want to use that method) and I am using a 3D printed thread section and motor retainer. It's a big fat spot on the back of the rocket.

The rocket uses papered balsa fins and I'd like to stick with that part of the design. The thickness of the taper is 3.6mm at the fat end and 2mm and the thin end. I'll have to use epoxy (or something else) to finish the taper. Unless I change the nozzle (and increase print time) I can't make the thin end any thinner. I'm trying to decide whether I should remake the fins so that they stick into the airstream the same amount as the would if I hadn't d*cked with the design or just live with the fat end being 3.6mm less (0.142"). It doesn't sound like much but it's 5.3%.

Like this:

Rocket assembled with motor and Av bay



Close-up of taper section assembled



Close-up of taper section disassembled. The wide part goes over the threads

 
Last edited:

cwbullet

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I am printing a jig to make igniters - several of them.
 
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