Hackaday Prize Entry: Mini DRO For A Lathe

A manual lathe has dial wheels to control the feed of the main carriage and the cross slide to help take cuts on the workpiece. These feed wheels always have some backlash and require frequent resetting of the “zero”. The usual process would be to take measurements on the workpiece with either a vernier caliper or a micrometer at intervals which requires stopping the machine, adding up to increased machine time. The addition of a digital readout not only simplifies the process, but also reduces machining time substantially. Since the DRO magnetic strips are directly attached to the cross slide, the effects of backlash are mitigated.

[Igor] has just such a manual lathe and built his own mini DRO unit from scratch a couple of years back. Most DRO’s have encoder strips and sensors attached to the cross slide with a larger display unit attached separately on a stalk, with wires running between the two. [Igor] kept things simple by building a unit that fit within the space constraints he had. His unit consists of just two sensor modules – each attached directly to the slide. The main unit houses a linear hall sensor, electronics, buttons, a small LCD and batteries. The second axis unit houses just the sensor with a cable connecting it to the main unit for data and power. At the heart of the system is a pair of NSE-5310 linear hall sensor encoder chips. These work in conjunction with multipole magnetic strips. The encoder provides a 12-bit output, and the magnetic strips have poles spaced 2 mm apart. This translates to a theoretical resolution of almost 0.5 microns, but of course, the machine mechanics limit the actual results. The encoder chips talk to an ATtiny2313 over the I2C bus. Three buttons and the power supply round-up the hardware. To run it off a single 1.5 V rechargeable battery, [Igor] used a boost converter to get 3.3 V. The 5 V needed for the LCD is obtained by a voltage doubler connected to a PWM output from the microcontroller and regulated by a Zener diode. The second sensor unit connects via a TRRS 3.5 mm socket.

He added a Bluetooth module as an after thought, but ran out of GPIO pins as well as program space and had to get creative to make it work. The plan was to transmit the data to an Android tablet which would work as a large, remote, wireless display. He never did use that feature though, being satisfied with the small LCD display. There’s several things that went wrong in the build, and if he were to replicate the project again, several changes and improvements would help. So if anyone plans on doing something similar, do check up [Igor]’s project logs first.

Reamer Regrinding Using a Toolpost Spindle

How often have you wished you could reduce the size of a drillbit? [Ben Katz] has a bunch of projects in mind that use a tight-tolerance 22mm bore–but he didn’t have a 22mm reamer handy. Rather than buy one, he thought, why not regrind a larger one to the right size?

He first ground down the shank to fit in the lathe’s drill chuck. Once it was loaded into the chuck,  he reground the edge of a 7/8″ (22.225mm) reamer, reducing its diameter down to 22mm by spinning it on his lathe in conjunction with a toolpost spindle with a grinding wheel attached. The final diameter was 21.995mm—off by 5 microns!

[Ben]’s homebuilt spindle is a cool project in itself, and we publish a lot of posts about those handy tools. Check out our pieces on a brushless DC motor used as a CNC spindle, and this 3D printer outfitted with a spindle. Also check out [Ben]’s electric tricycle build we featured a few years ago.

Continue reading “Reamer Regrinding Using a Toolpost Spindle”

Wearable Superconductors

What do you do with a discarded bit of superconducting wire? If you’re [Patrick Adair], you turn it into a ring.

Superconducting wire has been around for decades now. Typically it is a thick wire made up of strands of titanium and niobium encased in copper. Used sections of this wire show up on the open market from time to time. [Patrick] got ahold of some, and with his buddies at the waterjet channel, they cut it into slices. It was then over to the lathe to shape the ring.

Once the basic shape was created, [Patrick] placed the ring in ferric chloride solution — yes the same stuff we use to etch PC boards. The ferric chloride etched away just a bit of the copper, making the titanium niobium sections stand out. A trip through the rock tumbler put the final finish on the ring. [Patrick] left the ring in bare metal, though we would probably add an epoxy or similar coating to keep the copper from oxidizing.

[Patrick] is selling these rings on his website, though at $700 each, they’re not cheap. Time to hit up the auction sites and find some superconducting wire sections of our own!

If you’re looking to make rings out of more accessible objects, check out this ring made from colored pencils, or this one made from phone wire.

Hacked Car Axle Yields Custom 90° Gearbox

Need a sturdy angle gearbox to handle power transmission for your next big project? Why not harvest a rear axle from a car and make one yourself?

When you think about it, the axle of a rear-wheel drive vehicle is really just a couple of 90° gearboxes linked together internally, and a pretty sturdy assembly that’s readily available for free or on the cheap. [Donn DIY]’s need for a gearbox to run a mower lead him to a boneyard for the raw material. The video below shows some truly impressive work with that indispensable tool of hardware hackers, the angle grinder. Not only does he amputate one of the half axles with it, he actually creates almost perfect splines on the remaining shortened shaft. Such work is usually done on a milling machine with a dividing head and an end mill, but [DonnDIY]’s junkyard approach worked great. Just goes to show how much you can accomplish with what you’ve got when you have no choice.

We’re surprised to not see any of [DonnDIY]’s projects featured here before, as he seems to have quite a body of hacks built up. We hope to feature some more of his stuff soon, but in the meantime, you can always check out some of the perils and pitfalls of automotive differentials.

Continue reading “Hacked Car Axle Yields Custom 90° Gearbox”

Hackaday Prize Entry: 3D Printed Mini-Lathe

Lathes can be big, powerful, dangerous machines. But sometimes there’s a call for making very small parts out of soft materials, like plastic and wood. For jobs like this, you could use something like this 3D printed mini-lathe.

The benefits of 3D printing a tool like this are plentiful. The design can be customized and refined by the end user; [castvee8] notes that the machine can be made longer simply by increasing the length of the lead screw and guide rails. The machine does rely on some metal parts and a motor; but the real power here is that if you can’t source the exact components, you can always customize the files to suit what you have on hand.

[castvee8] aimed to make the entire build as easy as possible for the novice – even the motor and speed controller are off-the-shelf modules. It’s a testament to the golden age we live in that an entire lathe can be built out of modules and 3D printed parts. The project makes up another member of the family of 3D printed tools [castvee8] is showing off on Hackaday.io.

Making an Inexpensive DRO

[Andrew] wanted a digital readout (DRO) for his mini lathe and mini mill, but found that buying even one DRO cost as much as either of his machines. The solution? You guessed it, he built his own for cheap, using inexpensive digital calipers purchased off eBay.

The DRO he created features a touch screen with a menu system running on an LPCXpresso, while smaller OLED screens serve as labels for the 7-segment displays to the right. The DRO switches back and forth between the lathe and mill, and while the software isn’t done, [Andrew] hopes to be able to transfer measurements from one machine to the other.

In a very sweet touch, [Andrew] hacked cheap digital calipers to provide measurements for each axis, where they provide a resolution of 0.01mm. There are six daughter boards, one for each caliper, and each has a PIC that converts from serial to I2C, freeing the main firmware from dealing with six separate data streams.

The DRO doesn’t have a case, [Andrew] has it positioned out of chip-range from either machine.

A previous DRO we featured in 2012 used an Android tablet as its display.

New Wisdom on Old Practices

Getting into machining is hard. From high-speed seel versus carbide to “old US iron” versus “new Asian manufacture” to simply choosing which drill bits to buy, many hard decisions must be made before one even has a chance to gain experience. Fear not, [Quinn Dunki] has created “a roadmap for how to get involved in this hobby.

We saw [Quinn’s] first entry in her lathe series back in January, and now the series is complete! Starting with the definition of a machine tool and ending with the famous Clickspring scriber and a multi-material pen, [Quinn] leaves no stone unturned. [Quinn’s] style contrasts with the likes of [ThisOldTony], [AvE] or [Clickspring], as she makes sure to include the gory details of everything, citing her dissatisfaction with most YouTube machinists as motivation:

they’re all about the money shots of chips flying, but thin on the actual work of machining, which is mostly work-holding setups, changing bits and dies around, etc. That’s where all the knowledge is. The machine does the work once you spend 20 minutes setting it up properly for the operation. Everyone skips that part. I scour Tubalcain videos for details like the angle of the compound for a facing operation, or how to drill a deep hole with a short tail stock without the carriage getting in the way. Simple things like that get glossed over, but stump a beginner.

Of the series, our favorite part was “Grinding tool bits.” When combined with [ThisOldTony’s] Grinding HSS Tools, the two form an education in high-speed steel tool grinding fit for a hacker. Need more than high-speed steel? We’ve got you covered.