AR Display Shows CNC Lathe Operations In Real Time

February 16, 2022 by Dave Rowntree 16 Comments

[Kent VanderVelden] has come up with an interesting AR system to assist operators who are monitoring CNC lathes. (video, embedded, below) The idea is to first produce a ‘frozen’ video stream of the workpiece. This was achieved by placing a high-speed camera above the lathe, and triggering an image capture, synchronized to the rotational position of the workpiece. A high-speed rotary encoder, attached to the tailstock via a belt drive, feeds the current position into an Altera Terasic DE-Nano FPGA eval board. This is then compared to the position from another encoder, doing duty as an angular set point control. The resulting signal is used as the camera trigger to generate a video stream of just the frames where the angle is as selected by the operator, thus giving the impression of a frozen position. The video stream is sent over to a client device based on a Raspberry Pi 4 with a UPS hat, allowing it to be portable.

High speed rotary encoder driven via a belt

This video stream is overlaid with details of the current machine position, as well as the LinuxCNC G-code being executed and a graphical representation of the operation being performed by the machine. This combined video is then fed to a Vufine VUF-110 wearable, which is minimally invasive, allowing the operator to clearly see the machine of interest. As [Kent] suggests, there are many possible usage scenarios for such a setup, including remote monitoring of multiple operating machines by a single operator.

We’ve seen a few neat machine hacks over the years, here’s a nice project adding a programmable power feed to an old lathe, and since wood lathes are often missing out some DRO love, here’s a nice way to tell them that you care.

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Machining Waveguides For 122 GHz Operation Is Delicate Work

February 12, 2022 by Lewin Day 21 Comments

Millimeter-wave Radars used in modern cars for cruise control and collision avoidance are usually designed to work at ranges on the order of 100 meters or so. With some engineering nous, however, experimenters have gotten these devices sending signals over ranges of up to 60 km in some tests. [Machining and Microwaves] decided to see if he could push the boat out even further, and set out machining some waveguide combiner cavities so he could use the radar chips with some very high-performance antennas.

Precision-machined components are required to successfully use these 122 GHz components for long-range transmissions.

The end goal of the project is to produce a 53 dBi antenna for the 122GHz signal put out by the mmWave radar chips commonly found in automotive applications. Working at this frequency requires getting tolerances just so in order to create an antenna that performs well.

Plenty of fine lathe work and cheerful machining banter later, and the precision waveguide is done. It may not look like much to the untrained eye, but much careful design and machining went on to make it both easy to attach to the radar and parabolic antenna system, and to make it perform at a high enough level to hopefully break records set by other enterprising radio experimenters. If that wasn’t all hard enough, though, the final job involved making 24 of these things!

There aren’t a whole lot of microwave antenna-specific machining channels on YouTube, so if you’ve been thirsty for that kind of content, this video is very much for you. If you’re more interested in antennas for lower frequencies, though, you might find some of our other stories to your liking. Video after the break.

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Electronic Lead Screws – Not Just For Threading Anymore

January 18, 2022 by Dan Maloney 6 Comments

An electronic leadscrew is an increasingly popular project for small and mid-sized lathes. They do away with the need to swap gears in and out to achieve the proper ratio between spindle speed and tool carriage translation, and that makes threading a snap. But well-designed electronic leadscrews, like this one from [Hobby Machinist], offer so much more than just easy threading.

The first thing that struck us about this build was the polished, professional look of it. The enclosure for the Nucleo-64 dev board sports a nice TFT display and an IP65-rated keyboard, as well as a beefy-looking jog wheel. The spindle speed is monitored by a 600 pulses-per-revolution optical encoder, and the lathe’s leadscrew is powered by a closed-loop NEMA 24 stepper. This combination allows for the basic threading operations, but the addition of a powered cross slide opens up a ton more functionality. Internal and external tapers are a few keypresses away, as are boring and turning and radius operations, both on the right and on the left. The video below shows radius-cutting operations combined to turn a sphere.

From [Hobby Machinist]’s to-do list, it looks like filleting and grooving will be added someday, as will a G-code parser and controller to make this into a bolt-on CNC controller. Inspiration for the build is said to have come in part from [Clough42]’s electronic leadscrew project from a few years back. Continue reading “Electronic Lead Screws – Not Just For Threading Anymore” →

A Nested Gear Clock

December 12, 2021 by Matthew Carlson 11 Comments

One of the most common projects we see here at Hackaday is a clock. It could just be that we as humans are fascinated by the concept of time or that making a piece of functional art appeals to our utilitarian sense. In that spirit, [Alexandre Chappel] set out to make a large mechanical clock with complex gears.

The initial design was made in Fusion360 over a week and then in a somewhat bold move, [Alexandre] started up the CNC and cut all the parts out of valchromat. The basic idea of the clock is that the numbers move on the clock, not the hands. So the clock should show 10:25 instead of moving hands to the 10 and the 5. Most of the clock is made of up stacked gear assemblies, geneva drives, and many bearings. A single stepper motor drives the whole clock, which [Alexandre] admits is a bit of a cheat since trying to add springs and an escapement would add complexity to an already complex clock. He did have to adjust and recut a few gears but most of the assembly came together nicely. Some 3d printed numbers dropped into the CNCed slots offers much-improved readability.

A few problems became apparent once the system was together. The numbers don’t quite line up perfectly, which is unfortunate. He mentioned that tighter tolerances on the gears would likely help there. A fatal design flaw on the smallest disk became apparent as it needs to turn a sixth of the circle whereas the outer circle is just turning a tenth of the circle. Mechanical advantage isn’t in [Alexandre’s] favor and the stepper skips some steps and it slowly makes its way towards the next second digit of the hour.

If you’re looking for more beautiful artistic clocks, why not check out this circuit sculpture one?

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Improving A Mini-Lathe With A Few Clever Hacks

November 13, 2021 by Dan Maloney 21 Comments

Like many budget machinists, the delightfully optimistically named [We Can Do That Better] had trouble with some of the finer controls on his import mini-lathe. But rather than suffer through it, he chose to rectify the machine’s shortcomings and in the process, teach everyone a bunch of great tips.

[We Can Do That Better]’s lathe retrofit focused on the carriage handwheel, which appears to lack proper bearings and wobbles around in a most imprecise manner. On top of that, the gearing of the drive made for an unsatisfying 19 mm of carriage travel per revolution of the handwheel. A single gear change made that an even 20 mm per rev, which when coupled with a calibrated and indexed handwheel ring greatly simplifies carriage travel measurements.

While the end result of the build is pretty great in its own right, for our money the best part of the video is its rich collection of machinist’s tips. The use of a wooden dowel and a printed paper template to stand in for a proper dividing head was brilliant, as was using the tailstock of the lathe to drive an engraving tool to cut the index lines. We’ve seen the use of a Dremel tool mounted to the toolpost to stand in for a milling machine before, but it’s always nice to see that trick used. And the mechanism for locking the dial to the handwheel was really clever, too.

Considering a mini-lathe? As encouraging as [We Can Do That Better]’s experience may be, it might be wise to take a deep dive into the pros and cons of such a machine.

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Heavy Metal Lathe Build Doesn’t Spare The Steel

October 27, 2021 by Dan Maloney 22 Comments

It’s common wisdom that the lathe is the essential machine tool, and the only one that can make copies of itself. While we won’t argue the primacy of the lathe in the machine shop, this scratch-built, heavy-duty lathe gives the lie to the latter argument — almost.

We’re used to seeing homebrew lathes, of course, and we’ve featured more than a few of them before. But two things make [Jornt]’s build stand out: how few specialized tools were needed to build it, and the sheer size and bulk of the finished product. Where most homebrew lathes tend to be the bench top variety and feature cast aluminum parts, [Jornt] went with steel for his build, and a lot of it. The base and bed of the machine are welded from scrap steel I-beams, and the ways are made from angle iron that has been ground flat with a clever jig to hold an angle grinder. The angle grinder plays a prominent role in the build, as do simple tools like a hand drill, files, and a welder — and yes, the unfinished lathe itself, which was used to bore out the bearing blocks for the headstock.

The completed lathe, powered by a treadmill motor in a way that [Jeremy Fielding] would no doubt endorse, comes in at a beefy 450 kg. It honestly looks like something you could buy from a catalog, and has most of the features of commercial machines. One thing we’d love to see on this lathe is the electronic lead screw that [James Clough] developed for his off-the-shelf lathe.

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Better Mousetraps (or Screw Drives) Don’t Always Win

August 4, 2021 by Al Williams 114 Comments

I’ve noticed, lately, that slotted screw heads are all but gone on new equipment. The only thing that I find remarkable about that is that it took so long. While it is true that slotted heads have been around for ages, better systems are both common and have been around for at least a century.

The reason slotted heads — technically known as the drive — are so common is probably because they are very easy to make. A hacksaw is sufficient for the job and there are other ways to get there, too. The only advantages I know of for the user is that you can easily clean a slotted drive and — possibly — use field expedient items like butter knives and quarters to turn the screw. I’ve heard people claim that it also is a feature that the screwdriver can pry things like paint can lids, but that’s a feature of the tool, not the screw drive.

The disadvantages, though, are significant. It is very hard to apply lots of torque to a slotted screw drive without camming it out or snapping the head off the screw. The screwdriver isn’t self-centering either, so applying force off-axis is common and contributes to the problem.

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