Converting A Scanning Electron Microscope Into A TEM Is Surprisingly Easy

June 13, 2026 by Maya Posch 6 Comments

Although both a SEM and a TEM are electron microscopes, their working principles and images are very different. Whereas an SEM uses secondary electrons ejected after bombarding a sample’s surface with primary electrons, a TEM works more like an X-ray machine, with a sensor placed behind the sample to record primary electrons after they pass through said sample. It is, however, possible to turn a SEM into a TEM with some creativity, as [ProjectsInFlight] recently did with his SEM.

We previously covered how the SEM in the video was saved from being scrapped and subsequently revived, and now it is getting a pretty nice upgrade. That said, this SEM to TEM change isn’t anything new, with so-called STEM imaging having been possible for ages using a rather simple reflecting adapter. The problem here is that such adapters cost enough to make you dread filing a budget request, yet they are simple enough that you might be able to DIY one.

The main concern with the DIY adapter was clearance between the sample holder and the fragile components inside the chamber. This turned out to be a hair under 14 mm (0.55″), giving not a lot of space to work with, but that was relative to the standard bulky sample holder. With a thinner sample plate machined out of aluminum, significantly more space became available, including for the primary electron mirror and shield for the secondary electrons.

Some more lathe, milling, and tapping work later, the entire sample holder came together. During testing a hack was implemented to enable adjusting the mirror angle while in the evacuated vacuum chamber so that the adapter could be dialed-in. Subsequently, a first sample was imagined in the form of gold nanoparticles, which revealed a leaky secondary electron shield due to bypassing.

Further testing revealed that the shield needed to extend much higher to meaningfully block secondary electrons, after which the TEM image massively improved. Subsequently, a previously expired mosquito graciously donated its wings to science, with TEM imaging clearly revealing the delicate structures within these wonders of evolutionary design.

The next challenge will be to TEM image biological cells, which require substantial preparation.

This isn’t the first STEM converter we’ve seen. The SEM has a long checkered history that we’ve talked about before, too.

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Hydraulic Drive For Your Lawn Tractor

June 3, 2026 by Jenny List 11 Comments

Most larger ride-around landscaping machinery has a similar transmission, a transaxle containing a gearbox, or in some cases, a continuously variable drive. [Made In Garage] has a Toro lawn tractor with just such a setup, and when the transaxle failed he replaced it with a hydraulic drive.

The video below is a classic bit of workshop porn, as he fabricates both the hubs and the rear frame to fit a pair of hydraulic motors. The throttle pedal is a hydraulic valve with the lever swapped for a pedal, and the hydraulic reservoir, in a nice touch, is an old fire extinguisher.

We’re not so sure about the pipework in such an exposed position under the machine as we think it would inevitably be damaged, but you can’t argue with the results. Having used a rough service mower with a hydraulic drive in the past, we appreciate always being exactly at the right ratio for the engine.

We think perhaps he should complement it with a loader.

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A Special Type Of Mower For Rocky Fields

May 29, 2026 by Bryan Cockfield 25 Comments

Ever since wealthy European landowners started displaying vast, unused swaths of turfgrass as status symbols, regular folk have been chasing that perfectly mown and tended lawn for similar reasons. In the modern era, most mowers used to maintain these spaces use a spinning blade attached to a motor of some sort, but this can be dangerous especially on rocky fields like [Greenhill Forge] needs to mow. For these fields it’s best to use a different type of mower, and he’s built one from scratch.

This type of mower is called a flail mower, which has hinged, sharpened hammers attached to a central rotating drum. Since the flails have less rotational speed at the ends, they are less dangerous if they strike solid objects like rocks. To build one, he first builds the central drum and flails, then the enclosure to mount it to his tractor, and then a drivetrain to attach it to the tractor’s PTO. Since everything is getting built in [Greenhill Forge]’s metalworking shop, many of the parts needed to be fabricated from scratch, which involved several jigs for the plasma cutter as well as forging some steel to make some of the thicker parts.

Although not many of us have fully-stocked metalworking shops like this, it shows that almost anything can be built with the right tools. A forge is actually fairly accessible for those looking to start smithing; we’ve seen them built from little more than an off-the-shelf unmodified microwave or from a propane torch and some cookware.

See Aerodynamics In Action With A Desktop Wind Tunnel

May 27, 2026 by Jenny List 9 Comments

While most of us don’t design aircraft or racing cars, it’s likely that we’re still fascinated by some of the aerodynamic studies behind them. But a full-sized wind tunnel is going to cost a small fortune, so how can we experiment? Never fear, because [luisengineering] is here with a 3D printable desktop wind tunnel.

There’s a build video that we’ve embedded below, and if you can sit through the continuous shilling of random tools, it’s an interesting watch. It’s an open design in that air is not recirculate through it, instead it passed through the machine from left to right. On the right is the fan, on the left the intake with a rectifier to ensure laminar flow. Then a constriction compresses and speeds up the air past the stage for the model under test, and an expansion slows it down again for the fan.

A wind tunnel needs a smoke generator to easily spot turbulence, and in this case a vape is called into action. The result is surprisingly effective, as we see with a demonstration using a small model car. Meanwhile if you’re interested in wind tunnels at this size, it’s not the first one we’ve brought you.

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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.