Reviving A Free 1990s Millport CNC Vertical Mill

June 28, 2024 by Maya Posch 25 Comments

When faced with the offer of free machining equipment, there is no realistic way to say ‘no’. This is how [Anthony Kouttron]’s brother [Thomas] got to pick up a large 1990s-era CNC machine as a new companion for his growing collection of such equipment. The trickiest part of the move to the new location was getting the machine to fit through the barn doors, requiring some impromptu disassembly of the Z-axis assembly, which required the use of an engine crane and some fine adjustments with the reinstallation. With that [Thomas] and [Anthony] got to gawk at their new prize in its new home.

This Millport vertical mill is effectively a Taiwanese clone of the Bridgeport vertical mill design, though using an imported servo control system from Anilam. The most exciting part about a CNC machine like this is usually the electronics, especially for a well-used machine. Fortunately the AT-style PC and expansion cards looked to be in decent condition, and the mill’s CRT-based controller popped up the AMI BIOS screen before booting into the Anilam S1100 CNC software on top of MS-DOS, all running off a 1 MB Flash card.

Which is not to say that there weren’t some issues to be fixed. The Dallas DS12887 real-time clock/NVRAM module on the mainboard was of course dead. After replacing it, the BIOS finally remembered the right boot and input settings, so that the CNC machine’s own controls could be used instead of an external keyboard. This just left figuring out the Anilam controls, or so they thought, as a range of new errors popped up about X-lag and the Distribution Board. This had [Anthony] do a deep-dive into the electronics cabinets to clean metal chips and repair broken parts and floating pins. After this and a replacement Anilam Encoder this Millport vertical mill was finally ready to be put back into service.

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What You Can See With A SEM?

June 19, 2024 by Al Williams 4 Comments

The last time we used a scanning electron microscope (a SEM), it looked like something from a bad 1950s science fiction movie. These days SEMs, like the one at the IBM research center, look like computers with a big tank poised nearby. Interestingly, the SEM is so sensitive that it has to be in a quiet room to prevent sound from interfering with images.

As a demo of the machine’s impressive capability, [John Ott] loads two US pennies, one facing up and one face down. [John] notes that Lincoln appears on both sides of the penny and then proves the assertion correct using moderate magnification under the electron beam.

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A Brief Look Inside A Homebrew Digital Sampler From 1979

June 17, 2024 by Dan Maloney 12 Comments

While we generally prefer to bring our readers as much information about a project as possible, sometimes we just have to go with what we see. That generally happens with new projects and work in progress, but it can also happen with old projects. Sometimes very old indeed, as is the case with this digital sampling unit for analog oscilloscopes, circa 1979.

We’ve got precious little to go on with this one other than the bit of eye candy in the video tour below and its description. Luckily, we’ve had a few private conversations with its maker, [Mitsuru Yamada], over the years, enough to piece together a little of the back story here — with apologies for any wrong assumptions, of course.

Built when he was only 19, this sampler was an attempt to build something that couldn’t be bought, at least not for a reasonable price. With no inexpensive monolithic analog-to-digital converters on the market, he decided to roll his own. A few years back he recreated the core of that with his all-discrete successive approximation ADC.

The sampler shown below has an 8-bit SAR ADC using discrete CMOS logic and enough NMOS memory to store 256 samples. You can see the ADC and memory cards in the homebrew card cage made from aluminum angle stock. The front panel has a ton of controls and sports a wide-range attenuator, DC offset, and trigger circuit with both manual and automatic settings.

It’s an impressive build, especially for a 19-year-old with presumably limited resources. We’ve reached out to [Yamada-san] in the hope that he’ll be able to provide more details on what’s under the hood and if this still works after all these years. We’ll pass along whatever we get, but in the meantime, enjoy.

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3D Printing A Bottle Labeling Assembly Line

June 16, 2024 by Tom Nardi 9 Comments

We’re not completely sure why [Fraens] needs to label so many glass bottles at home. Perhaps he’s brewing his own beer, or making jams. Whatever the reason is, it was justification enough to build an absolutely incredible labeling machine that you could mistake for a piece of industrial gear…if it wasn’t for the fact that majority of the device is constructed out of orange 3D printed plastic.

As we’ve come to expect, [Fraens] has documented the build with a detailed write-up on his site — but in this case, you’ve really got to watch the video below to truly appreciate how intricate the operation of this machine is. Watching it reminded us of an episode of How It’s Made, with the added bonus that you not only get to see how the machine functions, but how it was built in the first place.

Nearly every part of the machine, outside the fasteners, smooth rods, a couple of acrylic panels, and a few sections of aluminum extrusion, were 3D printed. You might think this would result in a wobbly machine with sloppy tolerances, but [Fraens] is truly a master of knowing when and where you can get away with using printed parts. So for example, while the glue rollers could be done in printed plastic, they still needed metal rods run through the middle for strength and proper bearings to rotate on.

Looking at the totality of this build, it’s hard to imagine how it could have been accomplished via traditional methods. Sure you could have sourced the rollers and gears from a supplier to save some plastic (at an added expense, no doubt), but there’s so many unique components that simply needed to be fabricated. For example, all the guides that keep the label heading in the right direction through the mechanism, or the interchangeable collars which let you select the pattern of glue which is to be applied. Maybe if you had a whole machine shop at your disposal, but that’s a lot more expensive and complex a proposition than the pair of desktop 3D printers [Fraens] used to crank out this masterpiece.

If the name (and penchant for orange plastic) seems familiar, it’s because we’ve featured several builds from [Fraens] in the past. This one may be the most technically impressive so far, but that doesn’t diminish the brilliance of his vibratory rock tumbler or cigarette stuffing machine.

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Busted: Toilet Paper As Solder Wick

June 14, 2024 by Dan Maloney 29 Comments

It didn’t take long for us to get an answer to the question nobody was asking: Can you use toilet paper as solder wick? And unsurprisingly, the answer is a resounding “No.”

Confused? If so, you probably missed our article a few days ago describing the repair of corroded card edge connectors with a bit of homebrew HASL. Granted, the process wasn’t exactly hot air solder leveling, at least not the way PCB fabs do it to protect exposed copper traces. It was more of an en masse tinning process, for which [Adrian] used a fair amount of desoldering wick to pull excess solder off the pins.

During that restoration, [Adrian] mentioned hearing that common toilet paper could be used as a cheap substitute for desoldering wick. We were skeptical but passed along the tip hoping someone would comment on it. Enter [KDawg], who took up the challenge and gave it a whirl. The video below shows attempts to tin a few pins on a similar card-edge connector and remove the excess with toilet paper. The tests are done using 63:37 lead-tin solder, plus and minus flux, and using Great Value TP in more or less the same manner you’d use desoldering braid. The results are pretty much what you’d expect, with charred toilet paper and no appreciable solder removal. The closest it comes to working is when the TP sucks up the melted flux. Stay tuned for the bonus positive control footage at the end, though; watching that legit Chemtronics braid do its thing is oddly satisfying.

So, unless there’s some trick to it, [KDawg] seems to have busted this myth. If anyone else wants to give it a try, we’ll be happy to cover it.

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This Open Source Active Probe Won’t Break The Bank

June 13, 2024 by Dan Maloney 19 Comments

If you’re like us, the oscilloscope on your bench is nothing special. The lower end of the market is filled with cheap but capable scopes that get the job done, as long as the job doesn’t get too far up the spectrum. That’s where fancier scopes with active probes might be required, and such things are budget-busters for mere mortals.

Then again, something like this open source 2 GHz active probe might be able to change the dynamics a bit. It comes to us from [James Wilson], who began tinkering with the design back in 2022. That’s when he learned about the chip at the center of this build: the BUF802. It’s a wide-bandwidth, high-input-impedance JFET buffer that seemed perfect for the job, and designed a high-impedance, low-capacitance probe covering DC to 2 GHz probe with 10:1 attenuation around it.

[James]’ blog post on the design and build reads like a lesson in high-frequency design. The specifics are a little above our pay grade, but the overall design uses both the BUF802 and an OPA140 precision op-amp. The low-offset op-amp buffers DC and lower frequencies, leaving higher frequencies to the BUF802. A lot of care was put into the four-layer PCB design, as well as ample use of simulation to make sure everything would work. Particularly interesting was the use of openEMS to tweak the width of the output trace to hit the desired 50 ohm impedance.

OpenSCAD Cranks Out Parametric CNC Clamps

June 11, 2024 by Tom Nardi 7 Comments

If you’ve ever used a CNC router or mill, you’ll know how many little things need to go right before you get anything resembling acceptable results. We could (and probably should?) run a whole series of posts on selecting the correct bit for the job at hand and figuring out the appropriate feeds and speeds. But before you even get to that point, there’s something even more critical you need to do: hold the workpiece down so it doesn’t blast off into orbit when the tool touches it.

Now that might sound like an easy enough job, and for basic flat stock, it often is. But if you’ve got an oddly shaped piece of material, you’ll quickly realize how inadequate those trusty c-clamps really are. When you get to that point, it might time to check out these OpenSCAD hold down clamps from [ostat]. Thanks to its parametric nature, you can plug whatever dimensions you need into the script, and in a few seconds it will spit out an STL file for a bespoke clamp that you can print out and put to work.

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