How Much Wood Can A Woodpecker Chuck?

It’s probably clear to a Hackaday reader that we live in a golden era for hobbyist tool accessibility. Cheap single board computers can be bought at any neighborhood RadioShack or Maplin. 3D printers sell fully assembled and ready to run for less than $200. Even the humble CNC mill has come down the price curve, though as you might expect at the low end things can get pretty rough. Like a cheap 3D printer, a cheap mill tends to be missing some basic features you’d expect any reasonable machine to have. If you get your hands on one of these little wonders, [Shahada Abubakar] has a pair of great blog posts on the basic set of upgrades you’ll probably want to perform right out of the box.

Which cheap CNC mills are we talking about? They go by a few names. Last year our own [Kristina Panos] put together a review of a shockingly inexpensive “1610” type sold by Linksprite (go take a read if you’re already considering a purchase!). The “1610” class, so named for it’s 16 cm x 10 cm bed size, is pretty common under a wide variety of manufacturer names. You can find them in this size made of 8020 like [Kristina] did or as “upgraded” versions cut from 1/4″ mystery plastic (often referred to in the listings as Bakelite, but your guess is as good as ours as to the true material). 1610 is the smallest size but basically the same machine exists as an 1810, 2418, or 3018. Each has a 775 size spindle and a single PCBA that handles stepper drive and runs grbl.

So what’s the problem? Well for one none of these machines have limit switches, though the controllers support them. [Shahada]’s guide has handy instructions for what kind to buy, how to wire them, and where they can be attached. Plus an overview of the G-code instructions to send the controller in order to home and configure everything properly. The controllers also like to be driven continuously over serial (though some sellers seem to offer a separate board to drive them). This is fine if you have a computer handy, but like a 3D printer it can be nice to bolt a Pi Zero or similar onto the unit and control it over the network. [Shahada]’s second post has a link to a mounting plate you can print for exactly that setup, as well as some suggestions for configuring CNC.js to drive everything.

Do you have one of these machines? Done any upgrades? Tell us in the comments! We’re always looking for ways to upgrade our home shop.

How To Build A Mill With Epoxy

The typical machine tool you’ll find in a workshop has a base and frame made of cast iron or steel. These materials are chosen for their strength, robustness and their weight, which helps damp vibrations. However, it’s not the only way to make a machine tool. [John McNamara] has been working on a CNC mill with an epoxy base, with impressive results.

The molds were designed in CAD prior to casting, ensuring there was room for all required components.

The build is one that could be readily achieved in any decently equipped makerspace. [John] used lasercut steel parts to construct the molds for the epoxy base, with some custom turned parts as well. The precision cut parts fit together with great accuracy, and with proper control of the casting process there is minimal post-processing of the final cast piece required. The mold is built with zero draft angle, and is designed to be taken apart to remove the finished pieces. By using steel, the same mold can be used many times, though [John] notes that MDF could be used for a one-off build.

The base is cast in epoxy, mixed with granite aggregate and sand to create a strong, heavy, and vibration damping material. There are also steel reinforcements cast in place consisting of threaded rods, and conduits for various electrical connections. After casting, [John] has spent much time measuring and truing up the mill to ensure the best possible results from the outset.

It’s an impressive build, that shows that building your own accurate machine tools is quite achievable with the right tools and knowledge. We’ve seen similar work before, too – epoxy really does make a great material for casting at home.


CNC Your Own PCB With This Tutorial

It is getting so easy to order a finished printed circuit board that it is tough to justify building your own. But sometimes you really need a board right now. Or maybe you need a lot of fast iterations so you can’t wait for the postal service. [Thomas Sanladerer] shows how he makes PCBs with a CNC machine and has a lot of good advice in the video below.

He starts with Eagle, although, you could use any creation package. He shows what parameters he changes to make sure the traces don’t get eaten away and how to do the CAM job to get the files required to make the boards. If you don’t use Eagle, you’ll need to infer how to do similar changes and get the same kind of output.

We’ve only heard a few people pronounce Gerber (as in Gerber file) with a soft G sound, but we still knew what he meant. We have the same problem with GIF files. However, once you have Gebers, you can join the video’s workflow about 5 minutes in.

At that point, he uses FlatCAM to convert the Gerbers to a single G-code file that integrates the paths and drill files. There were a few tricks he used to make sure all the tracks are picked up. Other tricks include leveling a spoil board by just milling it down and mounting different size bits. He also has ideas on aligning the Z axis.

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Scratch Built Toe Clamps Keep Your Work In Place

[Kevin] owns a benchtop CNC mill that has proven itself to be a capable tool, but after becoming familiar with some of its shortcomings, he has made a few modifications. In order to more efficiently hold and access workpieces on his custom fixturing table, he designed and made his own toe clamps and they look beautiful.

The usual way to secure a piece of stock to a fixturing table is to use top-down clamps, which hold the workpiece from the top and screw down into the table. However, this method limits how much of the stock can be accessed by the cutting tool, because the clamps are in the way. The most common way around this is to mount a vise to the table and clamp the workpiece in that. This leaves the top surface completely accessible. Unfortunately, [Kevin]’s benchtop Roland MDX-450 has a limited work area and he simply couldn’t spare the room. His solution was toe clamps, which screw down to the table and have little tabs that move inwards and downward. The tabs do the work of clamping and securing a piece of stock while maintaining a very low profile themselves.

The clamp bases are machined from stainless steel and the heads are brass, and the interface between the two is a set screw. Inserting a hex wrench and turning the screw moves the head forward or back, allowing a workpiece to be clamped from the sides with minimal interference. His design was done in Fusion 360 and is shared online.

Another option for when simple clamps won’t do the job is a trick from [NYC CNC], which is to use an unexpected harmony of blue painter’s tape and superglue which yields great results in the right circumstances.

A Three Axis Mill For The End Of The World

A mill is one of those things that many hackers want, but unfortunately few get their hands on. Even a low-end mill that can barely rattle its way through a straight cut in a piece of aluminum is likely to cost more than all the other gear on your bench. A good one? Don’t even ask. So if something halfway decent is out of your price range, you might as well throw caution to the wind and build one.

That’s more or less the goal behind this extremely basic three axis mill built by [Michael Langeder]. Designed around a cheap rotary tool, it’s hard to imagine a more simplistic mill. Almost all the components are stuff you could pick up from the local hardware store, or probably even the junk pile if you were really in a pinch. It won’t be the best looking piece of gear in your shop, but it’s good enough to learn the basics on and just might be able to bootstrap a second-generation mill RepRap-style.

Made out of scrap blocks of aluminum and some threaded rod, the Z axis itself represents the bulk of the work on this project. It gives the user fine control over the height of the rotary tool by way of a large knob on the top. It’s held over the work piece with some flat steel bars and corner brackets rather hastily cut out of aluminum sheet.

While the tool holder is 3D printed, you could probably hack something up out of a block of wood if you didn’t have access to a printer. The only part of the mill that’s really “cheating” is the cross slide table, but at least they can be had for relatively cheap. If you really wanted to do this with junk bin finds, you could always replicate the Z axis design for X and Y.

If you’re not looking for something quite so austere, we’ve covered slightly more advanced DIY mills in the past. You could always go in the opposite direction and put a cross slide vise on your drill press, but do so at your own risk.

The How And Why Of Tungsten Carbide Inserts, And A Factory Tour

It seems a touch ironic that one of the main consumables in the machining industry is made out of one of the hardest, toughest substances there is. But such is the case for tungsten carbide inserts, the flecks of material that form the business end of most of the tools used to shape metal. And thanks to one of the biggest suppliers of inserts, Sweden’s Sandvik Coromant, we get this fascinating peek at how they’re manufactured.

For anyone into machining, the video below is a must see. For those not in the know, tungsten carbide inserts are the replaceable bits that form the cutting edges of almost every tool used to shape metal. The video shows how powdered tungsten carbide is mixed with other materials and pressed into complex shapes by a metal injection molding process, similar to the one used to make gears that we described recently. The inserts are then sintered in a furnace to bind the metal particles together into a cohesive, strong part. After exhaustive quality inspections, the inserts are ground to their final shape before being shipped. It’s fascinating stuff.

Coincidentally, [John] at NYC CNC just released his own video from his recent jealousy-inducing tour of the Sandvik factory. That video is also well worth watching, especially if you even have a passing interest in automation. The degree to which the plant is automated is staggering – from autonomous forklifts to massive CNC work cells that require no operators, this looks like the very picture of the factory of the future. It rolls some of the Sandvik video in, but the behind-the-scenes stuff is great.

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Air Wrench Becomes A Milling Machine Power Drawbar

We sometimes wonder if designers ever actually use their own products, or even put them through some sort of human-factors testing before putting them on the market. Consider the mechanism that secures toolholders to the spindle of a milling machine: the drawbar. Some mills require you to lock the spindle with a spanner wrench, loosen the drawbar with another wrench, and catch the released collet and tool with – what exactly?

Unwilling to have the surgical modifications that would qualify him for the Galactic Presidency, [Physics Anonymous] chose instead to modify his mill with a power drawbar. The parts are cheap and easily available, with the power coming from a small butterfly-style pneumatic wrench. The drawbar on his mill has a nearly 3/8″ square drive – we’d guess it’s really 10 mm – which almost matches up with the 3/8″ drive on the air wrench, so he whipped up a female-to-female adapter from a couple of socket adapters. The wrench mounts to a cover above the drawbar in a 3D-printed holster. Pay close attention to the video below where he goes through the Fusion 360 design; we were intrigued by the way he imported three orthogonal photos on the wrench to design the holster around. That’s a tip to file away for a rainy day.

This is a great modification to a low-cost milling machine. If you’re in the process of buying machine tools, you should really check out our handy buyer’s guides for both milling machines and lathes. It’ll let you know what features to look out for, and which you’ll have to add later.

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