Intro to Practical 3D Printing

This is the next installment in my series on 3D Printing. This time we’ll talk about how to do practical 3D printing. You know, the useful DIY kind. I think everyone should own a 3D printer. If you’re considering getting one, read that. If you’re interested in getting a 3D printer of your own or you just bought one knowing nothing, then I wrote this article on getting started for you, but this isn’t for you yet. You can do it! But you have to take it one thing at a time. This is for when you’re comfortable printing toys off the web.

This article assumes you have successfully 3D printed one thing you are happy with that has supports. If you know how to print most basic shapes, you can start making your own objects.

Find A Simple Project

I’ve had this cheap Google Cloud PopSocket on my phone for years and this past month my toddlers tore it off. They broke one of the tabs on it. Good news was it still stayed on with 3 tabs. It was partly my fault. I had jammed it in their drawers to act like a TV they sat under.

RIP In Pepperonis

So I set it on the floor for them to watch their cartoons with. They. Broke. It. Again. Seriously? It seems they literally pulled it off on purpose, and broke a second tab, so it was unfixable. Cheap plastic thing, so I decided to 3D print a replacement.

This is such a trivial process for me (to reverse-engineer a shape) that I spent a lot of time documenting it to show how it’s done. This makes a perfect example for a practical 3D printing project.


Step one is to find out how big what you’re making needs to be.

Measure, measure, measure, measure, measure.

If you don’t have a pair of calipers, GET SOME. It’s $20 at your local hardware store. They don’t need to be fancy.

Measure everything you can possibly think of and sketch it out on paper. I like engineering paper because the graph is subtle and barely there. Usually you’re replacing something simple that is plastic that broke. Alternatively, you can just measure as you go, but you’ll keep having issues with not knowing a certain dimension so you’ll keep going back to measure again.

Engineering paper > plain graph paper

It’s ok if you don’t get the measurements exact, try to get a number within 0.1mm you’re happy with. A typical 3D printing filament like mine has a 0.4 nozzle, so divide by 0.4 to see how thin things will be. If you’re trying to print something thinner than that you’re going to have a bad time. You probably want everything to be at least 0.8mm thick or so. And things won’t be exact, the slicing tools like CURA are going to round and approximate.

Oh, and if you’re an American like I am, get used to using metric if for some reason you aren’t. It’s just better for these kinds of things.

Modeling Time

I use a free license of Fusion360. Blender is neat for artistic models but for practical creations you want to use an engineering tool. I’m not going to teach you Fusion360 here but there are excellent YouTube videos, look some up yourself.

If your thing is round like mine, make half of it and extrude, spinning it around the center. After I did that it was a simple matter of drawing the tab at the right place, spinning it to make 4 copies, and extruding them at the same point, finally merging those bodies with the main one. Most of this project was taking pictures for you and waiting on the export to an STL file. It took only 18 min to print.


Printing direction – when you design something, it’s going to be weak in the vertical direction, so generally long things that need to be strong shouldn’t be printed up and down. The sides of something will be the prettiest and highest detail. The bottom will be flat or ugly, if you have something rounded the round side should go on top. These are just general 3d printing rules. They didn’t matter in my case. You’ll have to make some decisions here if any of these matter a lot to you for a project.

Utility – Practical 3D printing often has more needs, like strength or durability. If that’s you, the type of filament you choose and the thickness and temperature you set your printer/gcode to in the slicer will matter.

Prototype first. Get something that fits and/or prints, and then you can worry about printing in a different direction or scaling up or adding fancy details.
That’s what this project was and here is my final project, where I made some SVGs myself and imported those shapes into Fusion360 to use in making a non-round pop socket! Ocarina of Time was the best game.

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