3D printing has been accessible to the hobbyist for quite a few years now, and in that time it has earned itself a reputation for being a bit of a toy — printing plastic busts of pop culture icons, Christmas ornaments, trinkets, and silly doodads. But the promise of a 3D printer is so much more than that. You can easily prototype and fabricate simple parts, tools, and jigs, either from your own designs or from online repositories.

Thingiverse and the popular subreddit /r/functionalprint are great places to get started putting your printer to practical use — you’ll be able to get your head around the sorts of problems that other 3D printing aficionados have solved, and the ways that they solved them. Conversely, you can just wait for something around your house to break. Sooner or later that oven knob will snap off or you’ll lose the battery cover to one of your remotes, and you’ll have an excuse to start designing or searching for a printable replacement file. (Tip: Search first; there’s a good chance that someone else has already designed the part you need.)

Designing your own parts is the way to really unlock the potential of a 3D printer. There are a handful of easily accessible design tools such as SketchUp and Tinkercad, but your time might be better invested in learning some of the more powerful CAD packages like Onshape or Fusion 360. Having some precision measuring tools, like a set of digital calipers, even cheap ones, will dramatically help with your designing process. You’re going to be designing parts that fit with other parts, and you’ll need precise measurements. Printing quick test probes to make sure your design fits is also a great practice; it helps to know that your parts are going to fit together correctly before you commit to a long print job, wasting time and material.

Photo by Richard Tran

Adding Hardware

Having a 3D printer might mean that you have a tiny factory on your desk, but it helps to have some extra bits on hand to help your printed parts work better together. Machine screws and nuts can make the process of joining two pieces together a snap, especially if they require occasional disassembly. Heat-set threaded inserts are a great way to add internal threads to your model to receive a machine screw, or you can model a hexagonal hole in your design to trap a hex nut. It’s a good idea to stick to a common screw diameter to simplify your design process, but make sure to get them in a variety of lengths to suit all of your applications. Bearings also make great additions to rotating parts, as well as neodymium magnets to attach your part to metal.

Photo by Peter Pokojný

Material Concerns

3D printed parts will almost universally be weaker than parts made through any other fabrication process, but that doesn’t mean that 3D printing can’t get the job done. Consumer FFF printed parts won’t hold up to high mechanical stresses, but there are plenty of design choices you can make to stack the deck in your favor. Parts will be weakest along their z-axis — the printing layers can separate or shear with enough force. If that’s where the stress will be on your part, design it to lie flat on the print bed to offset this aspect. Chamfers and fillets can also make a part far more rigid, as can different infill patterns and densities. Your printing material is worth considering as well — ABS tends to shrink as it cools, but is more flexible and less brittle than PLA. If your printer can reach higher temperatures, you can use stronger exotics like nylon, PETG, and polycarbonate. Then again, the great aspect of 3D printing is the ease of replacement — you can just keep printing spares as you need them.

Once you get the sense for how to design and print parts that solve problems, however minor, you’ll likely soon find that your view of the world has transformed — when you find yourself wishing that a specific part existed to solve your unique problem, you’ll find yourself with the capability of creating your own solution. Whether you need a very specific mounting bracket, a jig to help you get more use out of a power tool, or maybe just some mounting hooks to help you keep your home or workshop more organized, 3D printing creates a huge opportunity space for you to design, create, and invent.

Photo by Gian-Luca Mateo

Practically Perfect

3D Printed Stethoscope

Doctors in disadvantaged or war-torn locations are printing their own implements; this stethoscope model costs just a couple of dollars in materials.

Photo by BWBarker

Cord-Cutting Antenna

Our airwaves abound with digital, high-definition television broadcasts, free for anyone with an antenna that can grab the signal. This fractal-based model is an effective design.

Photo by initnull

Bike Light Replacement Handlebar Mount

My old headlight mount didn’t fit around my new bike’s fatter handlebar in a way that I was happy with, so I quickly modeled this one in Fusion 360.

Photo by Tyler Winegarner