What If You Could Design Your Own Aluminum Hand?

[Ian Davis] has decided to start over on his hand. [Ian] is missing four fingers on his left hand and has for a year now been showcasing DIY prosthetics on his YouTube channel. Back in July, we covered [Ian]’s aluminum hand.

Why aluminum? [Ian] found himself reprinting previous versions’ 3D printed plastic parts multiple times due to damage in the hinged joints, or UV damage rendering them brittle. With an ingenious splaying mechanism and some sensors powered by an Arduino, [Ian] has been wearing the custom machined aluminum hand on a daily basis.

However, as with many makers, he had that itch to revisit and refine the project. Even though the last version was a big jump in quality of life, he still found room for improvement. One particular problem was that the sensors tended to shift around and made it hard to get an accurate reading. To overcome this, [Ian] turned to a molding process. However, adding a stabilizing silicon layer meant that the design of the prosthetic needed to change. With several improvements in mind, [Ian] started the process of creating the plaster positive of his palm, working to create a silicon negative. The next step from here was to create a fiberglass shell that can go over the silicone with sensor wires embedded into the fiberglass shell.

It has been amazing to see the explosion in 3D printed prosthetics over the past few years and hope the trend continues. We look forward to seeing the next steps in [Ian’s] journey towards their ideal prosthetic!

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Homemade Gear Cutting Indexer Blends Art With Engineering

Ordinarily, when we need gears, we pop open a McMaster catalog or head to the KHK website. Some of the more adventurous may even laser cut or 3D print them. But what about machining them yourself?

[Uri Tuchman] set out to do just that. Of course, cutting your own gears isn’t any fun if you didn’t also build the machine that does the cutting, right? And let’s be honest, what’s the point of making the machine in the first place if it doesn’t double as a work of art?

[Uri’s] machine, made from brass and wood, is simple in its premise. It is placed adjacent to a gear cutter, a spinning tool that cuts the correct involute profile that constitutes a gear tooth. The gear-to-be is mounted in the center, atop a hole-filled plate called the dividing plate. The dividing plate can be rotated about its center and translated along linear stages, and a pin drops into each hole on the plate as it moves to index the location of each gear tooth and lock the machine for cutting.

The most impressive part [Uri’s] machine is that it was made almost entirely with hand tools. The most advanced piece of equipment he used in the build is a lathe, and even for those operations he hand-held the cutting tool. The result is an elegant mechanism as beautiful as it is functional — one that would look at home on a workbench in the late 19th century.

[Thanks BaldPower]

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Teaching An Old Lathe New Tricks With A Programmable Power Feed

Ask anybody whose spent time standing in front of a mill or lathe and they’ll tell you that some operations can get tedious. When you need to turn down a stainless rod by 1/4″ in 0.030″ increments, you get a lot of time to reflect on why you didn’t just buy the right size stock as you crank the wheel back and forth. That’s where the lead screw comes in — most lathes have a gear-driven lead screw that can be used to actuate the z-axis ( the one which travels parallel to the axis of rotation). It’s no CNC, but this type of gearing makes life easier and it’s been around for a long time.

[Tony Goacher] took this idea a few steps further when he created the Leadscrew Buddy. He coupled a beautiful 1949 Myford lathe with an Arduino, a stepper motor, and a handful of buttons to add some really useful capabilities to the antique machine. By decoupling the lead screw from the lathe’s gearbox and actuating it via a stepper motor, he achieved a much more granular variable feed speed.

If that’s not enough, [Tony] used a rotary encoder to display the cutting tool’s position on a home-built Digital Readout (DRO). The pièce de résistance is a “goto” command. Once [Tony] sets a home position, he can command the z-axis to travel to a set point at a given speed. Not only does this make turning easier, but it makes the process more repeatable and yields a smoother finish on the part.

These features may not seem so alien to those used to working with modern CNC lathes, but to the vast majority of us garage machinists, [Tony]’s implementation is an exciting look at how we can step up our turning game. It also fits nicely within the spectrum of lathe projects we’ve seen here at Hackaday- from the ultra low-tech to the ludicrously-precise.

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A Bit Of DIY Helps Cut Straight And Happy Threads

A cheap and effective ratcheting tap.

Need to cut threads into a hole? A tool called a tap is what you need, and a hand-operated one like the one shown here to the side is both economical and effective. A tap’s cutting bit works by going into a pre-drilled hole, and it’s important to keep the tool straight as it does so. It’s one thing to tap a few holes with steady hands and a finely calibrated eyeball, but when a large number of holes need to be tapped it can be worth getting a little help.

The usual tool to help keep a tap straight and pressed gently downwards is called a tap follower, but [Tony] had a lot of M4 holes to tap and no time to order one and wait for it to arrive. Instead, he converted a cheap tap into a tool that could be held in the chuck of his mill, with the freedom to slide up and down as needed. The result? A tap that’s hand-operated but certain to be orthogonal to the work piece, making the job of cutting a lot of threads much more pleasant.

Tapping isn’t just for metal, either. Cutting threads into wood is also done, and be sure to check out this simple method for making your own surprisingly effective wood taps in the shop with a threaded rod, or a lag screw. Of course, the need to tap a hole can be sidestepped by using threaded inserts in the right material, instead.

A Special Baseball Bat With Explosive Hitting Power

To make up for some lacking athletic ability, [Shane Wighton] of [Stuff Made Here] created a custom baseball bat with an explosive sweet spot, that almost guarantees a home run. Inside a custom machined bat, he added a piston mechanism, powered by blank cartridges intended for powder actuated nailers, that can hit a ball with impressive force.

Up to three rimfire blank cartridges are placed in the stationary side of the piston mechanism, and are fired by three firing pins on the back of the piston when a ball hits the front of the piston. The expanding gasses then drive the piston out at high velocity, hitting the ball, before it is stopped from flying out completely by a crossbar. The gasses are exhausted through the side of the sleeve, into a “muffler” machined into the front of the bat. The first time [Shane] fired the mechanism with two cartridges, it almost sheared off the stopping bar, and damaged all the other components and blew the bat apart. This led to a complete redesign, including a crossbar with urethane dampers and an aluminum muffler.

The results with the “upgrades” are pretty impressive, and a little scary. Batting distance was around 350 feet with two cartridges, hitting the ball off a tee to avoid putting a pitcher in the firing line. [Shane] did a lab test with three cartridges, which put a hole in the ball and looked like it would break the bat. He expects that three cartridges would allow him to break the home run record, but would require another redesign and will be left for a future video

We admit to being rather envious of [Shane]’s workshop, and the projects that come out of it. We’ve seen him create an all-in-one golf club, a robotic barber, and a robotic basketball hoop, to name a few.

Linux In The Machine Shop Hack Chat

Join us on Wednesday, July 8 at noon Pacific for the Linux in the Machine Shop Hack Chat with Andy Pugh!

From the time that numeric control started making inroads into machine shops in the middle of the last century until relatively recently, the power of being able to control machine tools with something other than a skilled human hand was evident. Unfortunately, the equipment to do so was expensive, and so NC technology remained firmly in the big shops, where a decent return on investment could be realized.

Fast forward a few decades, and everything that makes the computerized version of NC possible is cheap and easily available. Servos, steppers, drivers, and motion control components can be plugged together into CNC machines that can move a tool to a fixed point in space with incredible accuracy and repeatability. But without CNC software, none of it means a thing.

Enter Linux CNC, the free and open-source CNC package. With support for realtime operation, one-step installations, and a huge range of capabilities provided by a team of volunteer developers and supported by an active community, Linux CNC has democratized the world of CNC machines.

Andy Pugh is a frequent contributor to the Linux CNC codebase and a moderator on the forum. He knows a thing or two about Linux CNC in particular and Linux in the machine shop in general. He’ll stop by the Hack Chat to share his experiences with the Linux CNC project, tell us how Linux can revolutionize the machine shop, and maybe share a few stories from the world of CAD, CAM, and using Linux to make a few chips.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, July 8 at 12:00 PM Pacific time. If time zones have you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.

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Measuring Sharpie Thickness… The Ink Itself, Not The Pen!

How we missed this one from a few years ago is unknown, but we’re glad to catch up with it now. Have you ever needed to measure how thick the ink in a Sharpie line is? Of course you haven’t. But if you needed to, how would you do it? Using a wicked-sensitive indicator gauge and levering an interesting test setup.

[Tom] from [oxtoolco] got his hands on a tool that measures in 1/10,000,000th (that’s one ten-millionth) increments and was wondering what kind of shenanigans you can do with this Lamborghini of dial indicators. It’s one thing to say you’re going to measure ink, but coming up with the method is the leap. In this case it’s a gauge block — a piece of precision ground metal with precise dimensions and perfectly perpendicular faces. By zeroing the indicator on the block, then adding lines from the Sharpie and measuring again, you can deduce the thickness of the ink markings.

After arraying diagonal lines on the gauge block it is placed lines-down under the dial indicator. This distributes the ink layer across a larger area, as probing the ink line directly would likely result in inaccurate readings. On that topic the gauge block is moved using pliers, as introducing heat from your fingers could result in expansion of the metal upsetting the readings.

The results? Black, blue, and red Sharpie were all tested, alongside blue and black Dykem layout fluid. Ten samples of each were run and the readings were all very close, save a couple of obvious outliers. Clocking in the thinnest is black Sharpie at about 118 millionths of an inch (~30 microns) and blue Dykem was the thickest at 314 millionths (86 microns). [Tom] quips that since we now know the thickness, you could even use ink as a shim.

If you can’t get enough Sharpie in your life, try it as an extremely satisfying add-on for your plasma cutter.

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