A mechanism made of brass and steel is attached to a milling machine. It has a long lever extending from the right side, a counterweight attached to the left side, and an indicator gauge in the middle.

A Precision Drill Press For Tiny Bits

May 16, 2026 by Aaron Beckendorf 11 Comments

Anyone who’s worked with even a 1 mm bit knows that while a drill press is all but essential, it isn’t proof against broken bits. Working with a 0.1 mm drill bit seems, therefore, all but impossible, which is why [Mike] of Chronova Engineering built this mechanism to simplify such drilling.

The mechanism is an attachment for a milling machine, and in principle it just needs to move the rotating drill bit up and down. It needs to be extremely precise, though. For context, a good-quality chuck normally has a runout of 30 to 50 microns, which is approaching half the diameter of the drill bit. The mechanism has a collet mounted in the milling machine’s spindle, which transfers rotation to a second spindle. The second spindle is mounted to a runout-compensating drill chuck, and is connected to a lever and counterweight which allow the user to make small, low-force movements. A dial indicator lets the user see how far the bit’s descended.

Most of the parts were machined out of steel or brass, with the handle being made of titanium for lower weight. When the finished device was mounted to the milling machine, the measured runout was severe. After much investigation and reworking, however, the problem turned out to be a damaged collet locating pin, not an issue with the drilling mechanism. As a first test, [Mike] drilled a 0.1 mm hole 1.8 mm deep, then as a challenge drilled six 0.1 mm holes in the end of a thin steel wire. The results weren’t quite as uniform as he wanted, but it took a scanning electron microscope to even see the imperfection.

It won’t help much with very fine drill bits, but if you need a very precisely-placed hole, check out this periscopic drilling camera. If you do break a drill bit in the workpiece, you might be able to dissolve it with alum.

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Building A Die Filer From Scratch

May 15, 2026 by Zoe Skyforest 21 Comments

A die filer is a useful tool to have if you find yourself filing parts on the regular. It’s basically a machine that reciprocates a file up and down for you so you can focus on filing the part to your desired dimensions. They’re not commonly manufactured these days, so [Richard Huberjohn] set about building his own.

This die filer relies on a simple mechanism to turn rotational motion from a motor into reciprocating linear motion in the vertical plane. A rotating shaft is connected to a crank, which turns a pin in a slotted carrier attached to a linear bearing. As the wheel turns, the pin slides in the carrier, driving it and the linear rod up and down in turn. Attach a file to this, and you have a working die filer. In this case, the rotating shaft is driven by a pair of DC brushed motors, with output stepped down via a gearbox and then a short belt drive. Speed is varied with the aid of an off-the-shelf controller.

If you’re regularly filing small parts, a build like this could speed your work to a great degree. We’ve featured other DIY machine tool builds before, too. If you’re cooking up your own gear for the home workshop, don’t hesitate to let us know on the tipsline!

A fine steel gear is shown held between a man's fingertips.

Cutting Steel Gears With Homemade EDM

May 5, 2026 by Aaron Beckendorf 17 Comments

Electric discharge machining (EDM) may be slower than alternatives like laser cutting, water jets, or a milling machine, but for some applications there’s no alternative: it can cut through any conductive material, no matter how hard, and it leaves no mechanical or thermal stress in the workpiece. Best of all, they’re relatively accessible for a resourceful hacker, such as [Inofid], who recently built the second iteration of his desktop wire EDM.

The EDM’s motion system comes from a cheap desktop CNC router, which had a water tank mounted in its workspace and had the spindle replaced with a wire-management mechanism. The wire-management mechanism needs to continuously wind a tensioned brass wire from one spool through the cutting zone onto another spool. The tensioning system uses two motors: one to pull the wire through, and one to maintain tension by slightly counteracting it, with a tension sensor and Ardunio to maintain the proper tension. If it detects that the wire has broken, it can stop the CNC controller. To keep the wire from breaking or short-circuiting with the workpiece, a current monitor counts sparks between the wire and workpiece and uses this to predict whether the wire is getting too close to the metal, in which case it slows down the movement.

As a first test, [Inofid] cut through a five by three centimeters-thick block of aluminium, taking two hours but producing a clean cut. To speed up the next cut, [Inofid] added a pump and filter to remove sludge from the cutting area. The next cut was an aluminium gear, and then a meshing steel gear, which took about ten hours but turned out well.

EDMs of various kinds appear here from time to time, particularly since the popularization of 3D printers. We’ve even seen one built into a lathe.

Thanks to [Keith Olson] for the tip!

This KiCAD Plugin Enables Breadboarding

April 23, 2026 by Dave Rowntree 17 Comments

Some people learning the noble art of electronics find the jump from simpler tools like Fritzing to more complex ones, such as KiCAD, a little daunting, especially since they need to learn at least two tools. Fritzing is great for visualising your breadboard layout, but what if you want to start from a proper schematic, make a prototype on a breadboard and then design a custom PCB? Well, with the Kicad-breadboard plugin for (you guessed it!) KiCAD, you can now do all of this in the same tool.

A simple dual-rail oscillator schematic corresponding to the featured image above

Originally designed to support EE students at the University of Antwerp, the tool presents you with a virtual breadboard with configurable size and style, along with a list of components and tools that can be placed. A few clicks and parts can be placed on the virtual breadboard with ease. Adding wires is the next logical step to make those connections that operate in the horizontal dimension. Finally, assigning power supplies and probe connections completes the process. It’s a simple enough tool to draw stuff, but drawing a layout is no use if you can’t verify it’s correctness. This is where this plugin shines: it can perform an ERC (check) between the schematic and the breadboard and flag up what you missed. Add to this that you can also perform an ERC at the schematic level, before even thinking about layout, and it’s pretty hard to make an error. Now, you can transfer this directly to a real breadboard, or even a veroboard, for more permanence once you have confidence in correctness. This will definitely save time correcting errors and help keep the magic smoke safely contained within those mysterious black rectangles.

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The Splice Must Flow

April 21, 2026 by Al Williams 45 Comments

There are plenty of electronic components out there, but the one we tend to forget is the most basic: wire. Sure, PC boards have largely replaced wire with copper traces, but most projects still need some kind of wire somewhere. Once you need any wire, there’s a good bet you will need longer wire, and that means splicing one wire to another. Simple, right? Not really. There are a variety of ways to splice wires, and which one you use depends on what you want to do and the type of wire you are using.

If the wires touch, good enough, right? Not necessarily. You need enough contact area for the current you are drawing through the wire to flow. It is also nice if the splice can survive some amount of mechanical strain, vibration, and survive getting hot and cold repeatedly.

Usually, after splicing, you’d like to solder the connection, although depending on the application, you don’t always see that. At the very least, you’d want to wrap it in electrical tape, use heat-shrink tubing, or otherwise insulate the bare wires and maybe provide a little mechanical support or strain relief.

Keep in mind that there are connector options, either mechanical, crimped, or soldered, that allow you to avoid splices. Soldering to a terminal strip, for example, or scewing wires into a barrier strip will get the job done. So will a butt connector, a wire nut, or a WAGO connector. But sometimes, for whatever reason, you just need to attach two wires to each other. It’s been done before.

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Modded Server PSU Provides Plenty Of Current

April 19, 2026 by Zoe Skyforest 20 Comments

Most makers find themselves in need of a benchtop power supply at some point or another. Basic models can be had relatively cheaply, but as your current demands go higher, so does the price. [Danilo Larizza] has figured out an alternative solution—repurposing old server hardware to do the job instead.

The build is based around an HP Common Slot (CS) server power supply. They can be readily had for well under $50 if you know where to look. Even better, they can deliver over 50 amps at 12 volts, which happens to be a very useful voltage indeed. All you need to do is some minor mods.

A jumper on a couple of pins will get the power supply running, and with the addition of some terminals for your hook-up leads, you’re ready to go. As a hot-swappable single unit, the power supply is already outfitted with a ventilation fan to keep everything cool. If so desired, you can even make some further mods to bump output voltage a little ways past 13 or 14 volts if you’d like to use them for certain battery charging tasks.

Sure, you’re not getting a variable power supply, but if you need 12 volts and lots of it, this is a great way to go. We’ve featured similar builds before, too, turning ATX PC power supplies into useful benchtop tools.

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FPGA Powers DIY USB Scope And Signal Generator

April 16, 2026 by Julian Scheffers 8 Comments

Oscilloscopes and to lesser extent signals generators are useful tools for analyzing, testing and diagnosing circuits but we often take for granted how they work. Luckily, [FromConceptToCircuit] is here to show us how they’re made.

[FromConceptToCircuit] starts by selecting the hardware to use: an Artix-7-based FPGA and an FT2232 USB-serial converter. RS245 in synchronous FIFO mode is selected for its high bandwidth of about 400 Mbps. Then, they show how to wire it all up to your FPGA of choice. Now it’s time for the implementation; they go over how the FT2232 interfaces with the FPGA, going through the Verilog code step-by-step to show how the FPGA makes use of the link, building up from the basic transmission logic all the way up to a simple framed protocol with CRC8-based error detection. With all that, the FPGA can now send captured samples to the PC over USB.

Now it’s PC-side time! [FromConceptToCircuit] first explains the physical pipeline through which the samples reach the PC: FPGA captures, transmits over RS245, FT2232 interfaces that with USB and finally, the software talks with the FT2232 over USB to get the data back out. The software starts by configuring the FT2232 into RS245 mode, sets buffer sizes, the whole deal. With everything set up, [FromConceptToCircuit] explains how to use the FT2232 driver’s API for non-blocking communication.

As a bonus, [FromConceptToCircuit] adds a signal generator feature to the oscilloscope using an I2C DAC chip. They start by explaining what exactly the DAC does and follow up with how it’ll be integrated into the existing system. Then it’s time to explain how to implement the I2C protocol bit-for-bit. Finally combine everything together for one final demo that shows a sine wave on the DAC’s output.