Help designing and printing a test tube

3D Fabrication
#1

3D Fab Community,

I’m Jeff Goodman. Prior to hiding out from COVID, I was an active member of the DMS woodshop/woodturning community. While hiding out at home, I am doing smaller projects on my Shopsmith 5-in-1 woodworking tool. I recently turned a small wooden vase from a plan in an old issue of Wood Magazine that calls for a nominally 1/2" X 3" test tube. Unfortunately, I can no longer source a glass or plastic tube that will work for the hole in the vase I’ve already drilled.

I’m looking for someone with 3D printing experience to help me with the design and printing. I contacted @themitch22 for advice before posting here and referred me to tinkercad.com. I went through some of the tutorials and quickly determined that although I might persevere and eventually get a reasonable design, it would be a much easier path to ask if someone could guide me through the whole process. I’m willing to pay for materials and negotiate to pay for someone’s time or barter for something I could make for/teach someone from the woodshop.

Anyone here up for the challenge of bringing an old wood guy into the 3d Fab world?

Jeff

#2

Can you chuck up an acrylic pen blank and turn a test tube? It wouldn’t be much different than turning an acrylic pen.

#3

Hey Jeff,

If you end up wanting to stick with 3D printing to learn some CAD and the 3D printing workflow, I’d be happy to meet up at the 'Space or jump on Zoom to walk through it sometime this weekend.

It’s been a while since I’ve used TinkerCAD, but I’d imagine a boolean subtraction of a small cylinder from within a larger cylinder would yield such geometry. Alternatively, in other CAD packages, running the Shell command on a cylinder primitive and using a “split bodies” operation to remove the top might be another method.

-Evan

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#4

Failing that, I did a quicky design for you using Fusion 360. It’s a parametric design with the following parameters, so it’s super easy to change:

OD: 0.500"
Length: 3.00"
Wall thickness: 0.040"

I did both a rimmed and a rimless design. I generated an .stl file for each. The .stl file is what would be sliced to print.

sketch
sketch888×306 36.9 KB

I can’t attach files here, but I put the F360 design and also the stl files into my folder on the member’s drive (I couldn’t find your folder).

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#5

Chris,

Wow, that’s why DMS is so valuable to me (and obviously others, as well). It never occurred to me to attempt such an elegant and simple solution as turning an acrylic pen blank. I turned wood pens years ago and briefly went into mass production to make sets for family and co-workers, then kinda lost interest and moved on to other things. I’ve never turned acrylic, but I might try that at some point.

I like your parametric design. I didn’t have a use for a members drive folder until now, as my only other files were MultiCam CNC files, which are buried on the committee drive. I created a member folder and copied your files into mine.

Thanks so much for taking the time to respond and do the basic design. I think I’ll poke around with Fusion 360 and TinkerCAD for a bit, then circle back around with @Evan_Lott to complete a printing prototype.

Thanks again, Jeff

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#6

Hey Evan,

Thanks for your reply. @John_Marlow already did the heavy lifting on a design, so I thought I’d take a look at that before doing anything else.

What’s your availability this weekend?

Jeff

#7

Sounds like a plan! I’ll PM you.

#8

Follow the instructions in this thread to get a free Solidworks license as a benefit of the membership:

Then follow these instructions to download and install the program:

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#9
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Fusion 360 Training?
#11

It depends on how many you need… I found this on the 'zon

https://www.amazon.com/Eisco-Rimmed-Borosilicate-Glass-Height/dp/B011M30FGM/

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#12

What do you hope to put in the tube?

#13

Why don’t you just go over to the @Science dept., and get a test tube? I think we have one to spare.

#14

Thanks Raymond,

Yeah, I did a million searches for test tubes and everything that I found were metric. I ordered a few 10mm X 75 mm, but they are obviously too narrow for the 9/16" hole that I’ve already drilled. I could find 12mm X 75, but any larger OD jumped to 100mm in length.

I don’t recall if I ever actually searched for 1/2" X 3" (perhaps thinking that even US mfg had converted to metric). Also, I was trying to avoid having to order so many.

Jeff

#15

Brian,

Water. The tube will go into a small wood turned bud vase.

Jeff

#16

Russell,

good point. I had that thought about that at one point, but probably dismissed it based on my searches.

Jeff

#17

I searched 3" and it popped up. It’s listed as .5" so a 1/2" fraction search wouldn’t have worked.

#18

Our FDM printers will not create sealed parts. Two thin coats of epoxy fixes that.

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#19

Brian,

oooh, thanks for that input. I have some epoxy that I used to bond some plastic stoppers to wood turned bottle stopper (JB weld Plastic Bonder - high strength structural adhesive, 2 part, 15 min) and some Loctite General Purpose 2 part, 5 min epoxy. I also have some Smooth-on epoxy that I bought at Reynolds Advanced Materials, down the street from DMS. I got it for filling large cracks in wood turned bowls, but it has enormous set up and cure times. What kind of epoxy do you suggest?

Man, it only takes me a step outside of the woodshop (where I barely know enough to be dangerous) to help me to understand how fricking little I know. I suppose that’s the life of a maker, eh?

Jeff

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