A Simple Touch Probe Made With Basic Tools

January 5, 2022 by Dave Rowntree 14 Comments

Six points of contact detect any displacement.

LinuxCNC contributor and machining enthusiast [Andy Pugh] is certainly not afraid to try making specialised tools to see how well they work out, and this time he’s been busy making a touch probe (video, embedded below) for checking the accuracy of machining operations and general measuring applications.

These things are not cheap, since they are essentially ‘just’ a switch with a long probe, But, as with anything specialised and machined with tight tolerances, you can understand why they cost what they do.

After inspecting and spending some time reverse-engineering such a unit, [Andy] then proceeded to grab some PEEK bar he had lying around and chuck it into the lathe (get it?). He notes Delrin would be more cost effective for those wishing to reproduce this, but as long as you have the ability to machine it and it’s non-conductive, there are many other options you could try.

Using no special tools other than a collet block (like this one) all the angled holes and slots were made with ease, with the help of a specially 3D-printed mount for the vise. A nice, simple approach, we think!

[Andy] tested the repeatability of the probe, mounted over his CNC-converted Holbrook lathe, reporting a value of 1 um, which seems rather good. Centering of the probe tip within the probe body was off a bit, as you’d expect for something made practically by hand, but that is less of a problem as it would seem, as it results in a fixed offset that can be compensated for in software. Perhaps the next version will have some adjustability to dial that out manually?

The whole assembly is formed from two plastic parts, a handful of ground-finished hardened steel pins, and a big spring. The only part remotely special is an off-the-shelf probe tip. During the electrical hookup, you may notice the use of a self-fluxing verowire pen, which was something this scribe didn’t know existed and has already placed an order for!

The reference 3D model for the design is shared from [Andy]’s Autodesk Drive for your viewing pleasure.

Of course, this isn’t the first DIY touch probe we’ve seen, here’s one for example, and over on Hackaday.IO, here’s an attempt to make one using a piezoelectric transducer.

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A Gorgeous Desk With AMD Inside

January 4, 2022 by Matthew Carlson 7 Comments

We’re the first to admit that we don’t see much woodworking here at Hackaday. But this desk with a PC inside from [John Heisz] is just too gorgeous not to share.

The build is mostly cherry veneered half-inch plywood and real cherry. There are dozens of angles and complex pieces that all fit together in a valuable and powerful desk. The centerpiece of the desk is the air intake grill with a 2019 Apple Mac Pro-like finish. [John] mentions that he previously did it by hand with just a parked drill bit and some patience, but he vastly prefers the automated way. Two cubbies flank the center vent, made from plywood with cherry veneers glued on. A USB hub is hidden at the back in one of the cubbies, exposing all the I/O for the AMD-powered desktop PC hidden inside. The top of the desk is hinged to allow easy access to the PC. [John] asserts that he made the coolest desk in the known universe. We don’t know if we can say it’s the coolest, but we certainly appreciate the process and expertise that made it.

After you’ve finished your new desk build inspired by [John]’s project, perhaps you might be interested in a levitating turbine desk toy to seal the deal. Video after the break.

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An OpenSCAD Library For All Your CNC Cutting Needs

January 2, 2022 by Tom Nardi 15 Comments

While there’s always the edge case, there’s a strong likelihood that if you’re using OpenSCAD, you’re probably working on a CAD model that you intend to 3D print at some point. Of course that’s not to say this is all you can do in OpenSCAD, but it’s arguably what it does best. If you wanted to make artistic models, or maybe render what your new kitchen will look like, there are other tools better suited to such tasks.

But thanks to lasercut.scad, a library that [Brendan Sleight] has been working on for the last several years, we might have to reconsider our preconceived dimensional notions. Instead of designing parts for 3D printing, his library is all about creating parts intended for subtractive manufacturing. Originally (as the name implies) it was geared towards laser cutting, but the project has since evolved to support CNC routers, vinyl cutters, and pretty much anything else that can follow a DXF file.

The library has functions for creating the standard tricks used to build things from laser-cut pieces, like finger joints, captive nuts, and assembly tabs. If it was something you once saw holding together an old wooden 3D printer kit back in the day, you can probably recreate it with lasercut.scad. It even supports a pretty wild piece of rotational joinery, courtesy of [Martin Raynsford].

Don’t have a way of concentrating a sufficient number of angry photons at your workpiece? No worries. The library has since been adapted to take into account a parametric kerf width, which lets you dial in how much of a bite your particular tool will take from the material when it does the business. There are even special functions for dealing with very thin cuts, which [Brendan] demonstrates by assembling a box from sheet vinyl.

Of course, those who’ve used OpenSCAD will know there’s not an “Export for CNC” button anywhere in the stock interface. So to actually take your design and produce a file your cutter can understand, [Brendan] has included a Bash script that will run the necessary OpenSCAD incantations to produce a 2D DXF file.

[Brendan] decided to send this one in after he saw the aluminum enclosure OpenSCAD library we covered recently. If you’ve got your own pet project that bends some piece of hardware or software to your will, don’t be shy to let us know.

Simple Mods Turn 3D Printer Into Electrochemical Metal Cutter

December 17, 2021 by Dan Maloney 30 Comments

We’re not aware of any authoritative metrics on such things, but it’s safe to say that the Ender 3 is among the most hackable commercial 3D printers. There’s just something about the machine that lends itself to hacks, most of which are obviously aimed at making it better at 3D printing. Some, though, are aimed in a totally different direction.

As proof of that, check out this Ender 3 modified for electrochemical machining. ECM is a machining process that uses electrolysis to remove metal from a workpiece. It’s somewhat related to electric discharge machining, but isn’t anywhere near as energetic. [Cooper Zurad] has been exploring ECM with his Ender, which he lightly modified by replacing the extruder with a hypodermic needle electrode. The electrode is connected to a small pump that circulates electrolyte from a bath on the build platform, while a power supply connects to the needle and the workpiece. As the tool traces over the workpiece, material is electrolytically removed.

The video below is a refinement of the basic ECM process, which [Cooper] dubs “wire ECM.” The tool is modified so that electrolyte flows down the outside of the needle, which allows it to enter the workpiece from the edge. Initial results are encouraging; the machine was able to cut through 6 mm thick stainless steel neatly and quickly. There does appear to be a bit of “flare” to the cut near the bottom of thicker stock, which we’d imagine might be mitigated with a faster electrolyte flow rate.

If you want to build your own Ender ECM, [Cooper] has graciously made the plans available for download, which is great since we’d love to see wire ECM take off. We’ve covered ECM before, but more for simpler etching jobs. Being able to silently and cleanly cut steel on the desktop would be a game-changer.

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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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Keep The Sparks Away With A Plasma Cutting Table

December 5, 2021 by Bryan Cockfield 8 Comments

For one-off projects or prototypes it’s not uncommon for us to make do with whatever workspace we have on hand. Using a deck railing as an impromptu sawhorse, for example, is one that might be familiar to anyone who owns a circular saw, but [Daniel] has a slightly different situation. He had been setting up metal workpieces on random chunks of brick in order to use his plasma cutter, but just like the home handyman who gets tired of nicking their deck with a saw, he decided to come up with a more permanent solution and built a custom plasma cutting table.

Plasma cutting has a tendency to throw up a lot of sparks, so most commercial offerings for plasma cutting tables include a water bath to catch all of the debris from the cutting process. [Daniel] builds his table over a metal tub to hold some water for this purpose. The table itself is built out of aluminum and designed to be built without welding even though most people with plasma cutters probably have welders as well. The frame is designed to be exceptionally strong and includes curved slats which add to the strength of the table. The table is also designed to be portable, so the curved slats stay in place when the table is moved.

While this might seem like an average metal table at first glance, the table is actually being designed with a homemade CNC machine in mind which [Daniel] is working on. The CNC plasma cutter needs a sturdy, flat surface and can’t be set up on bricks in the driveway, so this table suits both [Daniel]’s immediate needs to not shower himself in sparks every time he cuts something and also his future CNC machine’s need for a sturdy, flat workspace. We look forward to seeing that build being completed but in the meantime take a look at this motorized plasma cutter which has the beginnings of a CNC machine if in one direction only.

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DIY CNC Uses Lots Of 3D-Printed Parts

November 5, 2021 by Al Williams 21 Comments

There are probably almost as many DIY CNC designs as there are DIY CNCs. And there’s nothing wrong with that! We really liked [maxvfischer’s] documentation on GitHub for a machine he made based on a design by [Ivan Miranada].

In addition to a complete bill of materials, there are Fusion 360 files and very good instructions. There are several tips that seemed like they would help even if you were building similar machines.

The machine uses HTD5M belts instead of the more prevalent lead screw design. Everything slides on MGN12H slides. There are detailed photographs covering not just the tricky parts but even how to extend the stepper motor wires.

The original design used a Makita RT0700C for the spindle, but [max] couldn’t find one of those, but found a similar version with the same dimensions.

The only tip we would add is to be careful using taps in a handheld drill. (Don’t ask us how we know that.) A drill press is safer, or you can even use a tap handle and do it the old-fashioned way.

The firmware is grbl on an Arduino, and there are complete instructions for setting that up, too. We were amazed at the number of pictures included along with the detailed description. If you were ever afraid you couldn’t duplicate a CNC project, this might be the one to tackle.

There are, of course, cheaper and simpler options with fewer capabilities. Some are even almost free courtesy of the local dumpster.