Human In The Loop: Compass CNC Redefines Workspace Limits

July 25, 2025 by Matt Varian 15 Comments

CNCs come in many forms, including mills, 3D printers, lasers, and plotters, but one challenge seems universal: there’s always a project slightly too large for your machine’s work envelope. The Compass CNC addresses this limitation by incorporating the operator as part of the gantry system.

The Compass CNC features a compact core-XY gantry that moves the router only a few inches in each direction, along with Z-axis control to set the router’s depth. However, a work envelope of just a few inches would be highly restrictive. The innovation of the Compass CNC lies in its reliance on the operator to handle gross positioning of the gantry over the workpiece, while the machine manages the precise, detailed movements required for cutting.

Most of the Compass CNC is constructed from 3D printed parts, with a commercial router performing the cutting. A Teensy 4.1 serves as the control unit, managing the gantry motors, and a circular screen provides instructions to guide the operator on where to position the tool.

Those familiar with CNC routers may notice similarities to the Shaper Origin. However, key differences set the Compass CNC apart. Primarily, it is an open source project with design files freely available for those who want to build their own. Additionally, while the Shaper Origin relies on a camera system for tracking movement, the Compass CNC uses four mouse sensors to detect its position over the workpiece.

The Compass CNC is still in development, and kits containing most of the necessary components for assembly are available. We’re excited to see the innovative creations that emerge from this promising new tool.

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A photo of a Stirling Engine attached to a bike

Building A Stirling Engine Bike

July 17, 2025 by John Elliot V 27 Comments

Over on his YouTube channel [Tom Stanton] shows us how to build a Stirling Engine for a bike.

A Stirling Engine is a heat engine, powered by the expansion and contraction of a working fluid (such as air) which is heated and cooled in a cycle. In the video [Tom] begins by demonstrating the Stirling Engine with some model engines and explains the role of the displacer piston. His target power output for his bike engine is 150 watts (about 0.2 horsepower) which is enough power to cycle at about 15 mph (about 24 km/h). After considering a CPU heatsink as the cooling system he decided on water cooling instead.

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Head To Print Head: CNC Vs FDM

June 23, 2025 by Tyler August 18 Comments

It’s a question new makers often ask: “Should I start with a CNC machine or a 3D Printer?”– or, once you have both, every project gets the question “Should I use my CNC or 3D printer?” — and the answer is to both is, of course, “it depends”. In the video embedded below by [NeedItMakeIt] you can see a head-to-head comparison for one specific product he makes, CRATER, a magnetic, click-together stacking tray for tabletop gaming. (He says tabletop gaming, but we think these would be very handy in the shop, too.)

[NeedItMakeIt] takes us through the process for both FDM 3D Printing in PLA, and CNC Machining the same part in walnut. Which part is nicer is absolutely a matter of taste; we can’t imagine many wouldn’t chose the wood, but de gustibus non disputandum est–there is no accounting for taste. What there is accounting for is the materials and energy costs, which are both surprising– that walnut is cheaper than PLA for this part is actually shocking, but the amount of power needed for dust collection is something that caught us off guard, too.

Of course the process is the real key, and given that most of the video follows [NeedItMakeIt] crafting the CNC’d version of his invention, the video gives a good rundown to any newbie just how much more work is involved in getting a machined part ready for sale compared to “take it off the printer and glue in the magnets.” (It’s about 40 extra minutes, if you want to skip to the answer.) As you might expect, labour is by far the greatest cost in producing these items if you value your time, which [NeedItMakeIt] does in the spreadsheet he presents at the end.

What he does not do is provide an answer, because in the case of this part, neither CNC or 3D Printing is “better”. It’s a matter of taste– which is the great thing about DIY. We can decide for ourselves which process and which end product we prefer. “There is no accounting for taste”, de gustibus non disputandum est, is true enough that it’s been repeated since Latin was a thing. Which would you rather, in this case? CNC or 3D print? Perhaps you would rather 3D Print a CNC? Or have one machine to do it all? Let us know in the comments for that sweet, sweet engagement.

While you’re engaging, maybe drop us a tip, while we offer our thanks to [Al] for this one.

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The PCB Router You Wish You Had Made

June 14, 2025 by Jenny List 41 Comments

The advent of cheap and accessible one-off PCB production has been one of the pivotal moments for electronic experimenters during the last couple of decades. Perhaps a few still etch their own boards, but many hobbiest were happy to put away their ferric chloride. There’s another way to make PCBs, though, which is to mill them. [Tom Nixon] has made a small CNC mill for that purpose, and it’s rather beautiful.

In operation it’s a conventional XYZ mechanism, with a belt drive for the X and Y and a lead screw for the Z axis. The frame is made from aluminium extrusion, and the incidental parts such as the belt tensioners are 3D printed. The write-up is very comprehensive, and takes the reader through all the stages of construction. The brains of the outfit is a Creality 3D printer controller, but he acknowledges that it’s not the best for the job.

It’s certainly not the first PCB router we’ve seen, but it may be one of the nicer ones. If you make a PCB this way, you might like to give it professional-looking solder mask with a laser.

Open Source CAD In The Browser

June 12, 2025 by Al Williams 43 Comments

Some people love tools in their browsers. Others hate them. We certainly do like to see just how far people can push the browser and version 0.6 of CHILI3D, a browser-based CAD program, certainly pushes.

If you click the link, you might want to find the top right corner to change the language (although a few messages stubbornly refuse to use English). From there, click New Document and you’ll see an impressive slate of features in the menus and toolbars.

The export button is one of those stubborn features. If you draw something and select export, you’ll see a dialog in Chinese. Translated it has the title: Select and a checkmark for “Determined” and a red X for “Cancelled.” If you select some things in the drawing and click the green checkmark, it will export a brep file. That file format is common with CAD programs, but you’ll need to convert, probably, if you want to 3D print your design.

The project’s GitHub repository shows an impressive slate of features, but also notes that things are changing as this is alpha software. The CAD kernel is a common one brought in via WebAssembly, so there shouldn’t be many simple bugs involving geometry.

We’ve seen a number of browser-based tools that do some kind of CAD. CADmium is a recent entry into the list. Or, stick with OpenSCAD. We sometimes go low-tech for schematics.

Supercon 2024: Sketching With Machines

April 28, 2025 by Lewin Day 2 Comments

When it comes to our machines, we generally have very prescribed and ordered ways of working with them. We know how to tune our CNC mill for the minimum chatter when its chewing through aluminium. We know how to get our FDM printer to lay perfect, neat layers to minimize the defects in our 3D prints.

That’s not what Blair Subbaraman came down to talk about at the 2024 Hackaday Supercon, though. Instead, Blair’s talk covered the magic that happens when you work outside the built-in assumptions and get creative. It’s all about sketching with machines.

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DIY Record Cutting Lathe Is Really Groovy

April 22, 2025 by Tyler August 12 Comments

Back in the day, one of the few reasons to prefer compact cassette tape to vinyl was the fact you could record it at home in very good fidelity. Sure, if you had the scratch, you could go out and get a small batch of records made from that tape, but the machinery to do it was expensive and not always easy to come by, depending where you lived. That goes double today, but we’re in the middle of a vinyl renaissance! [ronald] wanted to make records, but was unable to find a lathe, so decided to take matters into his own hands, and build his own vinyl record cutting lathe.

photograph of [ronald's] setup — [ronald’s] record cutting lathe looks quite professional.

It seems like it should be a simple problem, at least in concept: wiggle an engraving needle to scratch grooves in plastic. Of course for a stereo record, the wiggling needs to be two-axis, and for stereo HiFi you need that wiggling to be very precise over a very large range of frequencies (7 Hz to 50 kHz, to match the pros). Then of course there’s the question of how you’re controlling the wiggling of this engraving needle. (In this case, it’s through a DAC, so technically this is a CNC hack.) As often happens, once you get down to brass tacks (or diamond styluses, as the case may be) the “simple” problem becomes a major project. Continue reading →