We recently gave you some tips on purchasing your first milling machine, but what we didn’t touch on was CNC (Computer Numerical Control) systems for milling machines (or other machines, like lathes). That’s because CNC is a complex topic, and it’s deserving of its own article. So, today we dive into what CNC is, how it works, and ultimately if it’s right for you as a hobbyist.
Is it possible to make an entertaining video about turning a cube of aluminum into a slightly cubier cube? As it turns out, yes it is, and you might even learn something along with the sight gags and inside jokes if you watch [This Old Tony] cover the basics of squaring up stock.
Whether you’re working in wood or metal, starting with faces that are flat, smooth and perpendicular is the key to quality results. [Tony] is primarily a machinist, so he works with a nice billet of aluminum and goes through some of the fundamental skills every metalworker needs to know. When you’re working down to the thousandths of an inch it’s easy to foul up, and tricks such as using a ball bearing between the vise jaws and the stock to prevent canting are critical skills. He covers tramming the mill, selecting which faces to cut and in which order, and ways to check your work on the surface plate and make any corrections if and when things go wrong. Look for cameos by fellow machinist [Abom79] and [Stefan Gotteswinter], including one with [Stefan] in a very compromising position. But a ball in a vise and no [AvE] reference? C’mon!
[Tony] makes a potentially tedious subject pretty entertaining by keeping things light, and we appreciate both the humor and attention to detail. He’s turned out some great videos that we’ve covered before, like making your own springs or a shop-built boring head, and his stuff is really worth checking out.
[This Old Tony] was cleaning up his metal shop after his yearly flirtation with woodworking when he found himself hankering for a nice coffee. He was, however, completely without a coffee making apparatus. We imagine there was a hasty round of consulting with his inanimate friends [Optimus Prime] and [Stefan Gotteswinter Brush] before he decided the only logical option was to make his own.
So, he brought out two chunks of aluminum from somewhere in his shop, modeled up his plan in SolidWorks, and got to work. It was designed to be a moka style espresso pot sized around both the size of stock he had, and three purchased parts: the gasket, funnel, and filter. The base and top were cut on a combination of lathe and mill. He had some good tips on working with deep thin walled parts. He also used his CNC to cut out some parts, like the lid and handle. The spout was interesting, as it was made by building up a glob of metal using a welder and then shaped afterward.
As usual the video is of [This Old Tony]’s exceptional quality. After quite a lot of work he rinsed out most of the metal chips and WD40, packed it with coffee, and put it on the stove. Success! It wasn’t long before the black stuff was bubbling into the top chamber ready for consumption.
A VMC (vertical machining center) is essentially a CNC vertical milling machine on steroids. Many CNC mills are just manual milling machines that have been converted to CNC control. They work nicely, but have a number of drawbacks when it comes to real world CNC milling: manual tool changes, lack of chip collection, lack of coolant containment, and backlash issues (which a manual machinist normally compensates for).
These problems are solved with a VMC, which will usually have an automatic tool changer, and an enclosure to contain coolant and wash chips down into a collection pan. They are, however, very expensive, very big, and very heavy. Building one from scratch is a massive undertaking, but one which [Chris DePrisco] was brave enough to take on.
Proxxon is a mostly German maker of above average micro tools. They do sell a tiny milling machine in various flavors, from manual to full CNC. [Goran Mahovlić] did not buy that. He did, however, combine their rotary tool accessory catalog into a CNC mill.
Owning tools is dangerous. Once you start, there’s really no way to stop. This is clearly seen with Goran’s CNC machine. At first happiness for him was a small high speed rotary tool. He used it to drill holes in PCBs.
In a predictable turn of events, he discovered drilling tiny holes in PCBs by hand is tedious and ultimately boring. So he purchased the drill press accessory for his rotary tool.
Life was good for a while. He had all the tools he needed, but… wouldn’t it be better if he could position the holes more quickly. He presumably leafed through a now battered and earmarked Proxxon catalog and ordered the XY table.
A realization struck. Pulling a lever and turning knobs! Why! This is work for a robot, not a man! So he pestered his colleague for help and they soon had the contraption under CNC control.
We’d like to say that was the end of it, and that [Goran] was finally happy, but he recently converted his frankenmill to a 3D printer. We’ve seen this before. It won’t be long before he’s cleaning out his garage to begin the restoration and ultimate CNC conversion of an old knee mill. Videos after the break.
If you have an old manual lathe, mill, or even a drill press, a digital readout (DRO) is a very handy tool to have. A DRO gives you a readout of how far you’ve cut, milled, or drilled into a piece of work without having to stoop to caveman levels and look down at a dial. Here’s a stupidly cheap DRO for all your machine tools. It should only cost five bucks or so, and if you need it, you already have the tools to manufacture it.
This build is inspired by an earlier build using the same single component – a digital tread depth gauge. This digital tread depth gauge is commonly found in countries that don’t use the US penny as currency to measure the depth of tread on a tire. The throw isn’t that large – only about 27mm – but with a few modifications it can fit on any machine tool.
The modifications include a small bit of metal glued to the back and four tiny neodymium magnets. For the ‘tool head’ of this DRO, only a tiny plastic collar and another deo magnet are needed.
This digital tire depth gauge looks like – and probably is – the same mechanism found in those super cheap calipers from the far east. In theory, it should be possible to extend this modification to those digital calipers, making for a simple DRO with a much larger throw.
Thanks [Ben] for sending this one in.
The title of ‘maker’ is conventionally applied to the young-adult age group. In the case of 84 year-old Ralph Affleck, a lifelong sawmiller, ‘maker’ perhaps undersells the accomplishment of building a fully functioning sawmill that can be operated by a single individual.
Starting in the trade at the age of 16 under his father’s tutelage, fifty years of working in sawmills saw him still loving what he did as retirement loomed. So, with pen, paper, and a simple school ruler he designed the entire shop from scratch. Decades of expertise working with wood allowed him to design the machines to account for warping and abnormalities in the timber resulting in incredibly accurate cuts.
With no other examples to guide his design — aside from perhaps old style steam-powered sawmills, and newer portable ones that he feels are inadequate for the job — much of the shop is built from scratch with scavenged parts. And, that list is impressive: four hydraulic cylinders from a Canberra bomber, levers from an old locomotive, differentials and gearboxes from a MAC and 1912 Republic trucks, a Leyland engine that operated for 13 years without the need for maintenance, and an assortment of old military and air force vehicle parts. This is complimented by his log skidder — also custom — that would look at home in a post-apocalyptic wasteland. Built from two tractors, it combines three gearboxes for 12 forward and 8 reverse gears(what!?), and can hit 42mph in reverse!