A person putting a screw into a CNC spoil board on the left of the image. Their drill is chartreuse and black. Clamps hold a rectangular board down at all four corners. The spindle of the CNC is just visible on the right hand side of the image.

Workholding Options For The Beginner CNC Operator

Designing a file to cut on a CNC is only part of the process. You also have to keep it in place while the machine does its work. [Garrett Fromme] walks us through five different work holding techniques.

Since every project is different and stock material can vary from thin veneer to much larger pieces, there’s no one right work holding method for every project, and not all methods are applicable to all materials. A vise is great for small projects that need to be held very securely and won’t be damaged, vacuum tables can make switching pieces quick in a production environment, fasteners will hold a piece securely at the expense of your spoil board, clamps are fairly versatile but fiddly to setup, and tape and CA glue are quick but require more consumables.

[Fromme] does a quick demonstration of setups with these different methods and their limitations, which is a great place to start for the beginner CNC operator. Just like 3D printers, CNCs are a far cry from the replicators in Star Trek that can automagically create what you ask it to, but proper workholding lets you waste less material and operate the machine more safely.

Our own [Elliot Williams] had a look at how CNCs aren’t as automated as you think. If you do need some CNC clamps, you might try these printable parametric clamps, or if you want something more beautiful, give these metal toe clamps a go.

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From Hoverboard To Scooter

I’m sure anyone who had seen Back To The Future was more than a little disappointed when “hoverboards” started appearing on the scene. They didn’t float and they looked fairly ridiculous for anyone over 12. But they have the huge advantage of being cheap and easy to find. [Made By Madman] breaks down a hoverboard for parts to make an incredible custom electric scooter.

The first step after breaking things down for parts was to break the wheel hub motors. He pulled out the axle and started machining a new one using the lathe and a milling machine. A quick temper later, he had a sturdy steel axle. An adapter for a disc brake was milled that could attach to the wheel. The TIG welder came out to weld up a box out of some aluminum to hold the electronics. The wheel had a bracket welded on with a spring shock absorber to help smooth the ride. The fork was machined on the lathe and belt sander, but actual shocks came from an old bicycle. To attach the fork to the frame, [Madman] bends a piece of bar stock into shape; like a madman. The handlebars were taken from the bicycle and the fork was extended up to an adult height.

A quick test ride in the alley showed that the back shock wasn’t strong enough, so he swapped it with a strong one. All the parts got a powder coat. Electronics wise, it has a standard speed controller and a custom battery made from 18650 cells wired up in a 13s6p configuration and bundled together into a package. After a significant amount of wiring, he took it for a test drove and we love seeing him zip around the streets in the snow.

So many parts here are machined to press-fit tolerances and then welded on. The skill, videography, and effort that went into this were just incredible. If you’re feeling inspired and don’t have a lathe on hand, perhaps this 3d printed scooter might be a bit more your speed. Video after the break.

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Self-Cleaning Camera Lens Makes For Speckle-Free Video

People making videos about machining have a problem: the coolant gets everywhere. When you take a video to show the process of creating a device, the milky gunk that keeps everything cool gets all over your camera lens. AvE is experimenting with an interesting fix for this problem, with a self-cleaning camera lens. (Video embedded below, some salty language.) His prototype uses a spinning piece of clear PVC mounted on BB gun pellets, driven by compressed air. The camera can see through this spinning piece, but when the coolant hits the spinning piece, it is thrown off.

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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.

CNC’d MacBook Breathes Easy

Sick of his 2011 Macbook kicking its fans into overdrive every time the temperatures started to climb, [Arthur] decided to go with the nuclear option and cut some ventilation holes into the bottom of the machine’s aluminum case. But it just so happens that he had the patience and proper tools for the job, and the final result looks good enough that you might wonder why Apple didn’t do this to begin with.

After disassembling the machine, [Arthur] used double-sided tape and a block of scrap wood to secure the Macbook’s case to the CNC, and cut out some very slick looking vents over where the internal CPU cooler sits. With the addition of some fine mesh he found on McMaster-Carr, foreign objects (and fingers) are prevented from getting into the Mac and messing up all that Cupertino engineering.

[Arthur] tells us that the internal temperature of his Macbook would hit as high as 102 °C (~215 °F) under load before his modification, which certainly doesn’t sound like something we’d want sitting in our laps. With the addition of his vents however, he’s now seeing an idle temperature of 45 °C to 60 °C, and a max of 82 °C.

In the end, [Arthur] is happy with the results of his modification, but he’d change a few things if he was to do it again. He’s somewhat concerned about the fact that the mesh he used for the grill isn’t non-conductive (he’s using shims of card stock internally to make sure it doesn’t touch anything inside), and he’d prefer the peace of mind of having used epoxy to secure it all together rather than super-glue. That said, it works and hasn’t fallen apart yet; basically the hallmarks of a successful hack.

It’s worth noting that [Arthur] is not the first person to struggle with the Macbook’s propensity for cooking itself alive. A few years back we covered another user who added vents to their Macbook, but not before they were forced to reflow the whole board because some of the solder joints gave up in the heat.

Lens Mount

X-Ray Imaging Camera Lens Persuaded To Join Micro Four Thirds Camera

Anyone who is into photography knows that the lenses are the most expensive part in the bag. The larger the aperture or f-stop of the lens, the more light is coming in which is better for dimly lit scenes. Consequently, the price of the larger glass can burn a hole in one’s pocket. [Anthony Kouttron] decided that he could use a Rodenstock TV-Heligon lens he found online and adapt it for his micro four-third’s camera.

The lens came attached to a Fischer Imaging TV camera which was supposedly part of the Fluorotron line of systems used for X-ray imaging. We find [Anthony’s] exploration of the equipment, and discovery of previous hacks by unknown owners, to be entertaining. Even before he begins machining the parts for his own purposes, this is an epic teardown he’s published.

Since the lens was originally mounted on a brass part, [Anthony Kouttron] knew that it would be rather easy to machine the custom part to fit standardized lens adapters. He describes in detail the process for cleaning out the original mount by sanding, machining and threading it. Along the way you’ll enjoy his tips on dealing with a part that, instead of being a perfect circle on the outside, had a formidable mounting tab (which he no longer needed) protruding from one side.

The video after the break shows the result of shooting with a very shallow depth of field. For those who already have a manual lens but lack the autofocus motor, a conversion hack works like a charm as well.

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Fixing A Broken Bandsaw With A Custom Steel Part

When a large bandsaw broke down due to a cast iron part snapping in two, [Amr] took the opportunity to record the entire process of designing and creating a solid steel replacement for the broken part using a (non-CNC) mill and lathe.

For those of us unfamiliar with the process a machinist would go through to accomplish such a thing, the video is extremely educational; it can be sobering both to see how much design work happens before anything gets powered up, and just how much time and work goes into cutting and shaping some steel into what at first glance looks like a relatively uncomplicated part.

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