Designing PLA To Hold Over A Metric Ton

November 27, 2025 by Ian Bos 10 Comments

There’s never been such a thing as being “too competitive” when it comes to competition. This is something that [Tom Stanton] from “Tim Station”, [Tom]’s 2nd channel, took to heart for Polymaker’s 3D design challenge. The goal was simple: a single 3D printed part to hold as much weight as possible.

While seemingly simple, when considering the requirements, including a single print in addition to being able to open up for the mounts, the challenge gets exponentially more complicated. While the simplest and strongest joint would be a simple oval for uniform stress, this isn’t possible when considering the opening requirements. This creates a need for slightly more creativity.

[Tom] starts out with two flat C-shaped geometries to test his design. The design includes teeth specially placed to allow the forces to increase their own strength as force is applied. Flat features have the unfortunate quality of being able to slide across each other rather easily, which was the case during testing; however, the actual structures held up rather well. Moving onto the final design, including a hollow cavity and a much thicker depth, showed good promise early on in the competition, leading up to the finals. In fact, the design won out over anything else, getting over double the max strength of the runner up. Over an entire metric ton, the piece of plastic proved its abilities far past anything us here at Hackaday would expect from a small piece of PLA.

Design can be an absolute rabbit hole when it comes to even the simplest of things, as shown with this competition. [Tom] clearly showed some personal passion for this project; however, if you haven’t had the chance to dive this deep into CADing, keep sure to try out something like TinkerCAD to get your feet wet. TinkerCAD started out simple as can be but has exploded into quite the formidable suite!

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Stack N’ Rack Your Hardware With The HomeRacker Project

November 27, 2025 by Donald Papp 7 Comments

Things are cooler when rack-mounted, and [KellerLab] aims to make that all far more accessible with the HomeRacker, a modular and 3D-printable rack building system designed to let you rack-mount to your heart’s content. While it can handle big things, it seems especially applicable to tasks like mounting one’s home network equipment and Raspberry Pi machines.

A rack is a great place for those Raspberry Pi servers and home networking equipment, but it can also handle bigger jobs.

The basic system (or core) consists of three different parts: supports, connectors, and lock pins. The supports are the main structural bars, the connectors mostly go at the corners, and the lock pins ensure everything stays put. The nominal sizing is a 15 mm x 15 mm profile for the supports, with lengths being a multiple of 15 mm.

All is designed with 3D printing in mind, and requires no tools to assemble or disassemble. There are design elements we really appreciate, like how parts are printed at an angle, which improves strength while eliminating the need for supports. The lock pins (and the slots into which they go) are designed so that they are effective and will neither rattle nor fall out.

But the core system is just the foundation. There’s plenty of modularity and expansions to handle whatever one may need, from Gridfinity shelves and drawers to various faceplates and other modules. There are some example applications available from [KellerLab]’s HomeRacker models page, like CD shelf, under-desk drawer, or filament rack.

[KellerLab] welcomes any collaboration, so check out the GitHub repository for CAD references and design files.

One last point to make about the value of printing objects like this at an angle: not only can the resulting layer lines provide better strength and reduce or eliminate the need for supports, but printing at an angle can help hide layer lines.

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Rare Filament Makes Weird Benchies

November 20, 2025 by Al Williams 21 Comments

[Zack], in addition to being a snappy dresser, has a thing for strange 3D printing filament. How strange? Well, in a recent video, he looks at filaments that require 445 C. Even the build plate has to be super hot. He also looks at filament that seems like iron, one that makes you think it is rubber, and a bunch of others.

As you might expect, he’s not using a conventional 3D printer. Although you might be able to get your more conventional printer to handle some of these, especially with some hacking. There is filament with carbon fiber, glass fiber, and more exotic add-ons.

Most of the filaments need special code to get everything working. While you might think you can’t print these engineering filaments, it stands to reason that hobby-grade printers are going to get better over time (as they already have). If the day is coming when folks will be able to print any of these on their out-of-the-box printer, we might as well start researching them now.

If you fancy a drinking game, have a shot every time he changes shots and a double when the Hackaday Prize T-shirt shows up.

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Making A Machine To Sort One Million Pounds Of LEGO

November 16, 2025 by John Elliot V 22 Comments

You know what’s not fun? Sorting LEGO. You know what is fun? Making a machine to sort LEGO! That’s what [LegoSpencer] did, and you can watch the machine do its thing in the video below.

[Spencer] runs us through the process: first, quit your day job so you can get a job playing with LEGO; then research what previous work has been done in this area (plenty, it turns out); and then commit to making your own version both reproducible and extensible.

A sorting machine needs three main features: a feeder to dispense one piece at a time, a classifier to decide the type of piece, and a distributor to route the piece to a bin. Of course, the devil is in the details.

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Concrete Lathe Turns Metal

November 9, 2025 by Al Williams 43 Comments

Full disclosure. If you want a lathe capable of turning metal stock, you probably should just buy one. But what fun is that? You can do like [kachurovskiy] and build one with your 3D printer. If you are chuckling, thinking you can’t make 3D printed parts sturdy enough, you aren’t exactly wrong. [Kachurovskiy’s] trick is to 3D print forms and then cast the solid parts in concrete. The result looks great, and we don’t doubt his claim that it “can surpass many comparable lathes in rigidity and features.”

Even he admits that this is a “… hard, long, and expensive project…” But all good projects are. There’s a GitHub page with more details and informative videos below. The action shots are in the last video just before the six-minute mark. Around the seven-minute mark, you can see the machine cut a conical thread. Color us impressed!

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Better 3D-Printed Bridges Are Possible, With The Right Settings

November 5, 2025 by Donald Papp 17 Comments

The header image above shows a completely unsupported 3D-printed bridge, believe it or not. You’re looking at the bottom of the print. [Make Wonderful Things] wondered whether unsightly unsupported bridges could be improved, and has been busy nailing down remarkably high-quality results by exhaustive testing of different settings.

It all started when they thought that unsupported bridges looked a lot as though they were made from ropes stretched between two points. Unlike normal layers, these stretched extrusions didn’t adhere to their neighbors. They are too far apart from one another, and there’s no “squish” to them. But could this be overcome?

His experiments centered mainly around bridge printing speed, temperature, and bridge flow. That last setting affects how much the extrusion from the hot end is adjusted when printing a bridge. He accidentally increased it past 1.0 and thought the results were interesting enough to follow up on; it seemed that a higher flow rate when printing a bridge gave the nudge that was needed to get better inter-line adhesion. What followed was a lot of testing, finally settling on something that provided markedly better results than the stock slicer settings. Markedly better on his test pieces, anyway.

BF = Bridge flow, BS = Bridge printing speed (in mm/sec)

The best results seem to come from tweaking the Bridge Flow rate high enough that extrusions attach to their neighbors, printing slowly (he used 10 mm/sec), and ensuring the bridged area is as consistent as possible. There are still open questions, like some residual sagging at corners he hasn’t been able to eliminate, but the results otherwise look great. And it doesn’t even require laying one’s printer on its side!

All the latest is on the project page where you can download his test models, so if you’re of a mind to give it a try be sure to check it out and share your results. Watch a short video demonstrating everything, embedded just under the page break.

Thanks to [Hari] for the tip!

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Print in place pump being used next to ladder

Print In Place Pump Pushes Limits Of Printing

November 4, 2025 by Ian Bos 5 Comments

3D printing has taken off into the hands of almost anyone with a knack for wanting something quick and easy. No more messing around with machining or complex assembly. However, with the general hands-off nature of most 3D prints, what could be possible with a little more intervention during the printing process? [Ben] from Designed to Make represents this perfectly with an entire centrifugal pump printed all at once.

This project may not entirely fit into the most strict sense of “print in place”; however, the entire pump is printed as one print file. The catch is the steps taken during printing, where a bearing is placed and a couple of filament changes are made to allow dissolvable supports to be printed. Once these supports are dissolved away, the body is coated with epoxy to prevent any leakage.

Testing done by [Ben] showed more than impressive numbers from the experimental device. Compared to previous designs made to test impeller features, the all in one pump could stand its own against in most categories.

One of the greatest parts of the open source 3D printing world is the absolute freedom and ingenuity that comes out of it, and this project is no exception. For more innovations, check out this DIY full color 3D printing!

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