Vintage Logan Lathe Gets 3D Printed Gears

January 13, 2018 by Tom Nardi 34 Comments

In December 2016, [Bruno M.] was lucky enough to score a 70+ year old Logan 825 lathe for free from Craigslist. But as you might expect for a piece of machinery older than 95% of the people reading this page, it wasn’t in the best of condition. He’s made plenty of progress so far, and recently started tackling some broken gears in the machine’s transmission. There’s only one problem: the broken gears have a retail price of about $80 USD each. Ouch.

On his blog, [Bruno] documents his attempts at replacing these expensive gears with 3D printed versions, which so far looks very promising. He notes that usually 3D printed gears wouldn’t survive in this sort of application, but the gears in question are actually in a relatively low-stress portion of the transmission. He does mention that he’s still considering repairing the broken gears by filling the gaps left by the missing teeth and filing new ones in, but the 3D printed gears should at least buy him some time.

As it turns out, there’s a plugin available for Fusion 360 that helpfully does all the work of creating gears for you. You just need to enter in basic details like the number of teeth, diametral pitch, pressure angle, thickness, etc. He loaded up the generated STL in Cura, and ran off a test gear on his delta printer.

Of course, it didn’t work. Desktop 3D printing is still a finicky endeavour, and [Bruno] found with a pair of digital calipers that the printed gear was about 10% larger than the desired dimensions. It would have been interesting to find out if the issue was something in the printer (such as over-extrusion) or in the Fusion 360 plugin. In any event, a quick tweak to the slicer scale factor was all it took to get a workable gear printed on the third try.

This isn’t the first time we’ve seen 3D printed gears stand in for more suitable replacement parts, nor the first time we’ve seen them in situations that would appear beyond their capability. As 3D printer hardware and software improves, it seems fewer and fewer of the old caveats apply.

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Star Chart Watch Is A Romantic Tragedy

January 10, 2018 by Tom Nardi 39 Comments

It’s becoming abundantly clear that [Colin Merkel] doesn’t know the definition of “good enough”. Not only has he recently completed his third (and most impressive) wristwatch build, but he also managed to put together one of the most ridiculously romantic gifts ever conceived. While some of us are giving our significant others a gift card to Starbucks, he made his girlfriend a watch with a chart on the face representing the position of the stars at the time and place of their first meeting.

As per his usual style, the documentation on this build is phenomenal. If paging through his gallery of build images doesn’t make you want to get a lathe and start learning metal working, nothing will. A chunk of stainless steel rod miraculously becomes a gorgeous wrist watch over the course of a few dozen images, perfectly encapsulating that old adage of “making it look easy”.

All you have to do is turn this into that. Easy.

Certainly the highlight of this build is the star chart on the face. To make it, he used PyEphem to plot the position of the brightest stars that were visible at the time and place of their first meeting. He then wrote a script to take those stars and convert their positions to G-Code the CNC could use to drill holes in the appropriate locations. The depth of the hole even corresponds to the magnitude (brightness) of each star, giving the chart a subtle 3D effect.

Unfortunately, [Colin] made a couple of mistakes during this build, to the point that he’s not exactly sure how to proceed. He mentions he might even be forced to start over from scratch. It’s hard to imagine how something that looks this good could ever end up being a failure, but the world of watch making is unkind.

To start with, he used 304 stainless instead of 303. This made machining the case much more difficult, and from his very first cut he realized it was going to be a problem. While it was an annoyance he mentions a couple times during the build log, he was at least was able to work through it.

The real problem came at the end, when he put the watch together. He originally made his designs assuming a front glass which was 0.5 mm thick, but in actuality used a piece that is 0.8 mm thick. This slight difference is just enough to cause the seconds hand to rub up on the glass, putting drag on the movement. The end result is that the battery dies extremely quickly, effectively rendering the watch useless.

We can’t imagine the heartbreak [Colin] felt when he realized what happened; we felt bad just reading about it. But given his track record, we have no doubt he’ll get the issue sorted out. It would be a shame to start over completely, but there’s some consolation in knowing it’s part of the learning process: you don’t become a master of your craft without making a couple mistakes along the way.

The predecessor to this watch was covered here at Hackaday last year, and made quite an impression. It’s interesting to see the improvements made between the two, and we’re certainly excited to see his next build.

Machined Lightsaber Pen For A More Civilized Age

December 18, 2017 by Tom Nardi 13 Comments

In an increasingly paperless society, writing implements are becoming an obsolete technology for many of us. Certainly not the kind of thing the average person would think to spend more than a couple bucks on, to say nothing of machining one out of a solid piece of aluminum bar stock. But clearly [Bob] is not most people. He recently dropped us a line about a video he uploaded to his aptly-named YouTube channel “Making Stuff”, where he goes through the steps required to turn raw materials into a writing instrument worthy of a Jedi.

Starting with a piece of aluminum chucked up in the lathe, [Bob] cuts out the iconic ribbed profile of Luke’s saber and fills in the gaps with nothing more exotic than a black Sharpie. He then moves on to the more complex shape of the emitter, and then flips the handle over in the lathe and hollows it out so a brass tube can be inserted.

Somewhat surprisingly, it seems more effort ends up being put into the acrylic “blade” than the aluminum handle itself. A chunk of acrylic is drilled and tapped so that it can be mounted in the chuck, and then turned down into a long cylinder. A tip is then cut in the end, the length of the blade is hollowed out, and finally it gets polished up to a nice shine.

The build is completed by inserting a standard ink pen cartridge down the center of the now completed saber. Surely the pen aficionados will lament that he didn’t attempt to build his own ink cartridge as well, but we think he gets a pass considering the rest of it was made from scratch.

If even a glorious writing instrument such as this isn’t enough to get you to re-learn how to write your name, fear not. Whether you’re making music or capturing flags, we’ve played home to numerous other saber projects; eye-safe or otherwise.

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Lathe Turns The Corner, Makes A Cube

November 13, 2017 by Kristina Panos 27 Comments

[Tim] was tired of using his lathe to turn round things. He decided to make a gaming die—something that’s iconically square—out of cylindrical scrap. As it turns out, this is possible to do on a lathe with a three jaw chuck. [Tim] discovered that the bevel on the jaws will hold a cylindrical puck of scrap sideways while he squares off the round sides into faces.

Turning a cube on a lathe looks pretty fiddly, so we applaud [Tim]’s lovely handiwork even more. As you’ll see in the video down below, things were going gangbusters until he went to make the last facing cut. Maybe the tool wasn’t lined up just so, or something was off in the chucking, but the first pass made a bit of a gouge in the stock. Looks like it was easy enough to fix, though. After four 90° turns and facing cuts, he had a nice looking rough cube to work with.

This is a regulation-sized die, so the next step was to trim it down to 16mm³. Then it was time to sand, polish, and add the dots. To lay them out, [Tim] sprayed the cube with layout fluid and scribed unique line patterns on each face. Then he drilled the indentations and filled them in with aluminium black.

Most of the dice we see are electronic, like this extremely random pair and these PIC-driven LED dice. We’d like to see [Tim] make a second D6 so he has a pair. And then make a D20. Please?

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Scratch Built Watch Case Is A Work Of Art

October 19, 2017 by Tom Nardi 33 Comments

The wristwatch was once an absolute necessity, as much fashion statement as it was a practical piece of equipment. Phones in our pockets (and more often than not, in our faces) replaced the necessity of the wristwatch for the majority of people, and the fashion half of the equation really only interests a relatively small subset of the population. The end result is that, aside from the recent emergence of smartwatches and fitness trackers, walking down the street it’s fairly unlikely you’ll see many people wearing a traditional watch.

But we think the scratch built wristwatch case recently shown off by [Colin Merkel] adds a new justification for wearing a watch: pride. From a chunk of steel rod stock, [Colin] walks through every step of the process to creating a professional looking watch case. This is actually his second attempt at the project; while his first one certainly didn’t look bad, he felt that he learned enough from his earlier mistakes that it was worth starting over from scratch. A man after our own heart, to be sure. Continue reading “Scratch Built Watch Case Is A Work Of Art” →

It’s A Wall-Mounted Dremel Workstation!

October 12, 2017 by John Baichtal 32 Comments

We’ve all seen Dremel drill presses, but [Tuomas Soikkeli] has created a full-fledged (albeit miniature) workstation using his Dremel as the motor. He has a gnome-sized belt sander with what appear to be skateboard wheels turning the belt, with the Dremel’s toolhead tensioning the belt and turning it as well. There’s a wee table saw, petite lathe, cute router, etc.

The Dremel attaches to the base via the 3/4-to-1/2 threaded end upon which specialized tool ends may be connected, and which DIY add-ons (like this light ring that we published previously) typical connect. Though in truth the threaded end varies in tensile strength from model to model — even the knockoffs have the same end, but is it strong enough to attach to the rig?

We like how [Tuomas] has his rig mounted to the wall. It looks like he has a couple of flexible shaft extenders nearby, allowing the rig to almost serve same role as a shop’s air tools.

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Fighting Machine Tool Chatter With A 555 Timer

October 6, 2017 by Dan Maloney 32 Comments

Vibration is a fact of life in almost every machining operation. Whether you’re milling, drilling, turning, or grinding, vibration can result in chatter that can ruin a part. Fighting chatter has generally been a matter of adding more mass to the machine, but if you’re clever about things, chatter reduction can be accomplished electronically, too. (YouTube, embedded below.)

When you know a little something about resonance, machine vibration and chatter start to make sense. [AvE] spends quite a bit of time explaining and demonstrating resonance in the video — fair warning about his usual salty shop language. His goal with the demo is to show that chatter comes from continued excitation of a flexible beam, which in this case is a piece of stock in the lathe chuck with no tailstock support. The idea is that by rapidly varying the speed of the lathe slightly, the system never spends very long at the resonant frequency. His method relies on a variable-frequency drive (VFD) with programmable IO pins. A simple 555 timer board drives a relay to toggle the IO pins on and off, cycling the VFD up and down by a couple of hertz. The resulting 100 RPM change in spindle speed as the timer cycles reduces the amount of time spent at the resonant frequency. The results don’t look too bad — not perfect, but a definite improvement.

It’s an interesting technique to keep in mind, and a big step up from the usual technique of more mass.

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