Faded Beauty DMM Gets An OLED Makeover

August 29, 2018 by Dan Maloney 24 Comments

When a fine piece of lab instrumentation crosses your bench, you’ve got to do your best to put it to work. But even in the highest quality devices no component lasts forever, especially vacuum tubes. For some vintage instruments with vacuum fluorescent displays, that means putting up with less-than-perfect digits in order to get that sweet, sweet precision. Or not – you can always reverse engineer the thing and add a spanking new OLED display.

The Hewlett-Packard 34401A digital multimeter that fell into [qu1ck]’s lap was a beauty, but it had clearly seen better days. The display was full of spuriously illuminated dots and segments, making it hard to use the 6.5 digit DMM. After a futile bit of probing to see if a relatively easy driver fix would help, and with a replacement display being made of solid unobtanium, [qu1ck] settled in for the long process of reverse engineering the front panel protocol. As luck would have it, H-P used the SPI protocol to talk to the display, and it wasn’t long before [qu1ck] had a decent prototype working. The final version is much more polished, with a display sized to fit inside the original space occupied by the VFD. The original digits and annunciator icons are recreated, and he added a USB port and the bargraph display show in the clip below.

We think it looks fabulous, and both the firmware and hardware are on Github if you’d like to rescue a similar meter. You may want to check our guide to buying old test gear first, though, to get the most bang for your buck.

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3D Printed Magnetic Dust Port Keeps Shop Clean

August 29, 2018 by Tom Nardi 33 Comments

Too often we hear that 3D printing is at best only a way for making prototypes before you invest in “real” manufacturing. At worst, it’s a way to make little toys for your desk or cubicle. The detractors say that 3D printing doesn’t lend itself to building practical devices, and even if you do manage to print something useful, you probably could have made it faster or better with more traditional manufacturing methods. So naturally we’re especially excited when we see a printed design that manages to buck both criticisms at once.

Not only does this magnetic dust port connector created by [Taylor Landry] have a clear practical purpose, but its design largely defies normal construction techniques. It consists of two flanges, sized for common 4″ flexible ducting, which feature embedded magnets on the faces.

This allows the two sides of the coupling to easily be connected and disconnected without relying on threads or a friction fit. Not only would threads likely get caked with sawdust, but the magnetic connection allows the coupling to release in the event somebody trips on the duct or the tool is moved.

Currently only one type of coupling is available, but [Taylor] says he’s looking at adapting the design to other tools. He also mentions that the magnets he’s currently using are a custom size he had left over from a previous project, so if you’re looking to replicate the design you might need to tweak the magnet openings. Luckily, he’s provided the STEP files so you don’t have to hack the STL.

A quick connect dust port like the one [Taylor] has come up with seems like it would be a perfect addition to the whole-shop dust collection systems we’ve covered in the past. In fact, it might not even be the only 3D printed component in the system.

A Scratch-Built Drill Press Vise From Scrap

August 29, 2018 by Dan Maloney 12 Comments

Never underestimate the importance of fixturing when you’re machining parts. No matter what the material, firmly locking it down is the key to good results, and may be the difference between a pleasant afternoon in the shop and a day in the Emergency Room. Flying parts and shattered tooling are no joke, but a lot of times quality commercial solutions are expensive and, well, commercial. So this scratch-built drill press vise is something the thrifty metalworker may want to consider.

To be sure, [Ollari’s] vise, made as it is almost completely from scrap angle iron, is no substitute for a vise made from precision ground castings. But it’s clear that he has taken great care to keep everything as square and true as possible, and we give him full marks for maximizing his materials. And his tools — nothing more complicated than a MIG welder is used, and most of the fabrication is accomplished with simple hand tools. We like the way he built up sturdy profiles by welding strap stock across the legs of the angle iron used for the jaws, to give them a strong triangular cross-section to handle the clamping force. And using the knurled end of an old socket wrench as the handle was inspired; we’ll certainly be filing that idea away for a rainy day in the shop. Although we might use Acme rather than plain threaded rod.

We always enjoy seeing someone fabricate their own tools, and this one reminds us a bit of the full-size bench vise built up from layers of welded steel we featured a while back. It even looks a little like this 3D-printed vise, too.

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A CNC Woodworking Tool That Does The Hard Parts

August 28, 2018 by Kerry Scharfglass 26 Comments

Drawn along in the wake of the 3d printing/home shop revolution has been the accessibility of traditional subtractive CNC equipment, especially routers and mills. Speaking of, want a desktop mill? Try a Bantam Tools (née Othermachine) Desktop Milling Machine or a Carvey or a Carbide 3D Nomad. Tiny but many-axis general purpose mill? Maybe a Pocket NC. Router for the shop? Perhaps a Shapeoko, or an X-Carve, or a ShopBot, or a… you get the picture. [Rundong]’s MatchSticks device is a CNC tool for the shop and it might be classified as a milling machine, but it doesn’t quite work the way a more traditional machine tool does. It computer controls the woodworker too.

At a glance MatchSticks probably looks most similar to a Pocket NC with a big Makita router sticking out the side. There’s an obvious X-axis spoilboard with holes for fixturing material, mounted to a gantry for Z-axis travel. Below the big friendly handle on top is the router attached to its own Y-axis carriage. The only oddity might be the tablet bolted to the other side. And come to think of it the surprisingly small size for such an overbuilt machine. What would it be useful for? MatchSticks doesn’t work by processing an entire piece of stock at once (that what you’re for, adaptable human woodworker) it’s really a tool for doing the complex part of the job – joinery – and explaining to the human how to do the rest.

The full MatchSticks creation flow goes like this:

Choose a design to make on the included interface and specify the parameters you want (size, etc).
The MatchSticks tool will suggest what material stocks you need, and then ask you to cut them to size and prepare them using other tools.
For any parts which require CNC work the tool will help guide the user to fixture the stock to its bed, then do the cutting itself.
Once everything is ready for final assembly the MatchSticks will once again provide friendly instructions for where to pound the mallet.

In this way [rundong], [sarah], [jeremy], [ethan], and [eric] were able to build a much smaller machine tool without sacrificing much practical functionality. It’s almost software-like in it’s focus on a singular purpose. Why reinvent what the table saw can do when the user probably already has access to a table saw that will cut stock better? MatchSticks is an entire machine bent around one goal, making the hard stuff easier.

It’s worth noting that MatchSticks was designed as an exploration into computer/human interaction for the ACM Conference on Human Factors in Computing Systems so it’s not a commercial product quite yet (we’re eagerly waiting!). For a much more in depth look at the project and its goals and learnings the full research paper is available here. Their intro video is down after the break.

Thanks [ethan] for the tip!

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See The Fabulous Workmanship In This Smart Pressure Regulator

August 28, 2018 by Donald Papp 8 Comments

For many projects that require control of air pressure, the usual option is to hook up a pump, maybe with a motor controller to turn it on and off, and work with that. If one’s requirements can’t be filled by that level of equipment and control, then it’s time to look at commercial regulators. [Craig Watson] did exactly that, but found the results as disappointing as they were expensive. He found that commercial offerings — especially at low pressures — tended to leak air, occasionally reported incorrect pressures, and in general just weren’t very precise. Out of a sense of necessity he set out to design his own electronically controlled, closed-loop pressure regulator. The metal block is a custom manifold with valve hardware mounted onto it, and the PCB mounted on top holds the control system. The project logs have some great pictures and details of the prototyping and fabrication process.

This project was the result of [Craig]’s work on a microfluidics control system, conceived because he discovered that much of the equipment involved in these useful systems is prohibitively expensive for small labs or individuals. In the course of developing the electronic pressure regulator, he realized it could have applications beyond microfluidics control, and created it as a modular device that can easily be integrated into other systems and handle either positive or negative pressure. It’s especially well-suited for anything with low air requirements and a limited supply, but with a need for precise control.

3D Printing A Printing Press

August 26, 2018 by Jenny List 3 Comments

If you move among artists, you may have encountered a few printmakers. They create a drawing by cutting through a wax layer that has been deposited on a sheet of copper, then etching the plate and removing the wax. Ink is then rolled onto the plate and cleaned from the flat surface, remaining in the cracks created by the etching. A print is made by putting inked plate and a sheet of paper through a roller press at significant pressure, squeezing the ink from the cracks onto the paper. The result is a beautiful print, but the press required to do the job is by no means cheap.

[Martin Schneider] has addressed this expense with his Open Press project, by producing a printmaking press that can be 3D-printed for a fraction of the outlay of a traditional press. It’s by no means a large model, but appears no less functional for it.

The form of the press is straightforward enough, with a print bed that is drawn between a pair of rollers by a rack-and-pinion gear, and as you would imagine the construction is quite substantial. It’s all CC licensed, and you can make one for yourself if you would like, by downloading the files from Thingiverse.

It’s fair to say that printmaking hasn’t appeared much here, but we can see this press could have significant use beyond artistic applications. Meanwhile it’s a great example of 3D printing providing the means to reduce the barrier to entry for something that was previously quite an expensive pursuit.

UnMaker 2.0 Is Wile E Coyote’s Dead Blow Hammer

August 25, 2018 by Lewin Day 13 Comments

Hammers! They’re good for knocking in nails, breaking things apart, and generally smashing up the joint, if you’re in such a mood. Typically, they’re made of iron or steel and come in a variety of sizes depending on the purpose — from tiny chipping hammers for delicate sculpture work, to the heavy-duty sledge for tearing through building materials. But what if you built your own comically large mallet? Enter UnMaker 2.0.

The hammer receiving an eye-catching lick of paint.

Basically, it’s a really big hammer. It’s vaguely reminiscent of a dead blow type design, in that it consists of a moderately shock-absorbing outer shell filled with heavier material. In this case, steel ball bearings find a home inside the shell made out of maple and with a traditional tapered handle. In many ways it’s quite a typical build — other than the fact of its gigantic size and 34-pound head weight. Both of these make it a shoe-in for the ACME catalog. That roadrunner won’t know what hit him.

[Kevin] reports that it is not so much “swung” as it is “raised and allowed to drop”, due to its impressive weight. Clearly, it packs a punch. It’s a solid follow-on from the group’s former work – a truly gigantic utility knife.