Lathe’s Tool Holder Holds a Rotary Tool

What is better than a tool? Two. What is better than two? Two tools tooling together. [tintek33] wanted a rotary tool to become an attachment on his mini lathe, the video is also below the break. Fortunately, Dremels and Proxxons are built to receive accessories, or in this case, become one. Even if the exact measurements do not apply to your specific hardware, we get to see the meat of the procedure from concept to use.

We start with where the rotary tool should be and get an idea of what type of bracket will be necessary. The design phase examines the important dimensions with a sketch and then a CAD mock-up. Suitably thick material is selected, and the steps for pulling the tool from the raw stock are shown with enough detail to replicate everything yet there is no wasted time in this video. That is important if you are making a quick decision as to whether or not this is worth your hard work. Once the brace is fully functional and tested, it is anodized for the “summer ocean” blue color to make it easy to spot in the tool heap. Some complex cuts are made and shown close-up.

Thank you [jafinch78] for your comment on Take a Mini Lathe for a Spin and check out [tintek33] using his mini lathe to make a hydraulic cylinder for an RC snow plow.

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Strobe For Wood Turning Makes Inspection Easy

The lathe is a simple enough tool to understand, but requires much practice to truly master. During the turning process, it’s often necessary to inspect the workpiece. This generally necessitates stopping the lathe, waiting for everything to spin down, and then starting again. This can be a major time sink when added up across the full scope of a project. However, the magic of strobes can help.

The basics of [Darcy]’s project will be familiar to any hacker who has worked with rotating machinery before. The rotational speed of the lathe is measured, in this case using a reed switch and a magnet. This signal is fed to a microcontroller, which controls the strobing of an LED lamp. By synchronizing the flashes to the speed of the lathe, it’s possible to view the workpiece as if it were standing still. By adjusting the offset of the flashes to the position of the lathe, it’s also possible to rotate this view to see the entire workpiece – all while the lathe remains spinning.

Further photos and videos are available in the Reddit thread. [Darcy] reports that despite his best efforts, he couldn’t quite find a business case for producing the hardware commercially, but the idea was too useful to leave languishing in a notebook. We’d love to hear your ideas on how this could improve turning projects, so be sure to let us know in the comments. If you’re just getting started with turning, it might be worth cutting a test bar to make sure your rig is up to snuff.

Sharpest Color CRT Display is Monochrome Plus a Trick

I recently came across the most peculiar way to make a color CRT monitor. More than a few oscilloscopes have found their way on to my bench over the years, but I was particularly struck with a find from eBay. A quick look at the display reveals something a little alien. The sharpness is fantastic: each pixel is a perfect, uniform-colored little dot, a feat unequaled even by today’s best LCDs. The designers seem to have chosen a somewhat odd set of pastels for the UI though, and if you move your head just right, you can catch flashes of pure red, green, and blue. It turns out, this Tektronix TDS-754D sports a very peculiar display technology called NuColor — an evolutionary dead-end that was once touted as a superior alternative to traditional color CRTs.

Join me for a look inside to figure out what’s different from those old, heavy TVs that have gone the way of the dodo.

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Cutting Wit And Plastic

If you have ever used a scalpel to cut something tougher than an eraser, you can appreciate a hot knife or better yet, an ultrasonic cutter. Saws work too, but they have their own issues. [This Old Tony] uses a hobby store tool to cut some plastic and wood, then demos a commercial ultrasonic cutter to show how a blade can sail through with less brute force. The previous requires some muscle, finesse, and eventually a splash of Bactine antiseptic. The video can also be seen after the break.

This is more than a tool review, [Tony] takes it apart with a screwdriver and offers his snarky comments. On the plus side is that it cuts polystyrene well where a regular knife won’t do more than scratch or shatter it. Meanwhile in the negative category we don’t hear a definitive price, but they seem to cost half as much as his mini-lathe. If you need an estimated return on investment, consider the price of two-thousand X-acto blades, but you may also wish to factor in the reduced hand calluses. While you are shopping, maybe also think about a set of earplugs; when the video gets to 17:30 he tries to cut a ceramic fitting and manages to make a child-deafening screech instead. We warned you.

This is a fitting follow-up to his unsuccessful attempt to turn an ultrasonic cleaner into an ultrasonic cutter, but we have seen success converting a tooth scaler into a cutter.

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The Coco-Nutcracker

Coconut is a delicious and versatile food but if you’ve ever tried to open one you know they can be a hard nut to crack. Those of us who live in the tropics where they are common might reach for a machete, drill, or saw to open them, which is often a messy and sometimes dangerous ordeal. Realizing that a coconut is just a large nut with a shell like any other, [Paul] of [Jackman Works] decided to build a nutcracker big enough to crack a coconut, which turns out to be almost exactly human-sized.

The nutcracker is built almost entirely out of reclaimed wood. Several rings made of many blocks of wood were constructed on the table saw before being glued and clamped together. Once the rings were stacked and glued to each other, [Paul] put them on a lathe to get a smooth finish. Then the arms, legs, body, and head were all assembled. The actual nutcracking mechanism is one of the few metal parts in this build, a long threaded rod which is needed to handle the large forces required for cracking the coconut.

Once the finishing touches were put on the nutcracker, including boots, a beard, some hair, and of course a pom-pom for his hat, [Paul] successfully tested it by cracking a coconut open. This build is exceptionally high quality and is definitely worth scrolling through. He runs a wood shop in DC where he builds all sorts of interesting things like this, including a giant wooden utility knife.

Ask Hackaday: Help Me Pick A CAD Package

Of all the skills that I have picked up over the years as an engineer, there is one that has stayed with me and been a constant over the last three decades. It has helped me work on electronic projects, on furniture, on car parts, robots, and even garments, and it is likely that I will continue using it periodically for the rest of my career. You see, I am a trained PAD expert.

Don't build this, it's fundamentally flawed! Sometimes the front of an envelope is as effective as its back.
Don’t build this, it’s fundamentally flawed! Sometimes the front of an envelope is as effective as its back.

PAD, you ask? OK, it’s an acronym of my own coinage, it stands for Pencil Aided Design, and it refers to the first-year undergraduate course I sat many years ago in which I learned technical drawing to the old British standard BS308. If I’m making something then by far the quickest way for me to visualise its design is to draw it, first a freehand sketch to get a feel of how everything will sit, then a series of isometric component drawings on graph paper with careful attention to dimensions and angles. Well, maybe I lied a little there, the graph paper only comes in when I’m doing something very fancy; the back of an envelope is fine as long as the dimensions on the diagram are correct.

An Envelope Will Only Take You So Far

Working on paper is fine for the situations in which I tend to use it, running bits of wood or sheet metal through a bandsaw or pillar drill, leaning on the sheet metal folder, and filing intricate parts to shape by hand. It’s quick and simple, and the skills are intuitive and long-held. But it is of course completely useless when applied to any computer-driven manufacturing such as a 3D printer, and for that I will need a CAD package.

I’m not averse to CAD and my holding out with paper is only due to familiarity, but I have to admit that I have never found a package to which I have successfully made the jump. My need for it has been too infrequent to either take the time to scale the learning curve or for my new-found knowledge to stick. Reaching for the trusty pencil has always been the easiest option.

Hacky Racers in action
Hacky Racers in action (Mark Mellors)

All this has however recently changed, for as regular readers may have noticed I have a bit of a thing for the British Hacky Racer series. If I am to perfect my design for a slightly ridiculous contraption that will clean up on the track, it makes sense that I crowd my hackerspace with little 3D-printed scale models before breaking out the welding equipment and hacking a frame together with 25mm OD square tube. I thus need to pick a CAD package, learn it, and set to work.

So what are my needs? I’m a Linux user, so while Windows-only software is worth talking about in the comments for other people it’s less useful for me unless it’s easy to run under WINE. It’s also worth making the point that while I’m not averse to paying for good software as I did for my PCB CAD package I’m not anxious to shell out business-grade sums for something I’ll use only occasionally. This is an arena in which many of the offerings are aimed at enterprises, and I simply can’t justify spending hundreds or thousands as they can.

Round up the Usual Suspects

Given those prerequisites, there are still quite a few options. In the open source arena there are SolveSpace and BRL-CAD which I have never tried, OpenSCAD which is probably not my cup of tea (change my mind if you like), and FreeCAD which has been my tool of choice for previous attempts to dabble. I must have missed some others, what are your thoughts? If I don’t mind free-as-in-beer software there’s always TinkerCAD in my browser, is that up to a Hacky Racer chassis design in 25mm square tube? And if I’m feeling brave enough to play with WINE then perhaps I can make something of RS DesignSpark Mechanical.

My trusty pencil has given me stalwart service over many decades, but while I’ll not be hanging it up entirely it’s time to move into the 21st century for my design work. Can you help me decide upon which CAD package will suit me best? Have I even found all the choices within my criteria? As always, the comments are open.

Make Your Own Dowels At Home

Dowels are a useful woodworking technology making it easy to connect several pieces of timber, particularly with the aid of adhesive. However, depending on where you live, it can be difficult to come by a wide variety of stock. This is particularly important if you’re concerned about appearances – cheap pine dowels could spoil the look of a delicately finished hardwood piece, for example.

Thankfully, it’s easy to make your own dowels at home. [Pask Makes] has used a simple dowel plate before, but this time, decided to build the deluxe version. A thick steel plate is drilled with a series of holes, and then mounted to a wooden block. Square stock can then be forced through the holes to produce the dowels.

[Pask] notes that there are several methods to use the dowel plate. Hammering the wood stock through the holes works best for hardwoods, while fitting the square stock into the chuck of a power drill and forcing it through while spinning gives a better finish on softer woods. There are also useful tips on how best to produce dowels, with notes on strength and grain orientation.

It’s a useful tool to have in your workshop, and means you can turn just about any wood into dowels for your woodworking projects. If you’re fresh to the world of wood, worry not – we’ve got the primer to get you started. Video after the break.

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