A frosted glass disk with geometrical markers

Using A Laser Cutter To Replicate An Optical Comparator Screen

Precision instruments often contain specialized components that are essential to their function, but nearly impossible to replace if they fail. [Andre] had just such a problem with an optical comparator, which is an instrument typically used in machine shops to help check the tolerances of a finished part. It does this by projecting a magnified picture of an object onto a glass screen with markings showing angles and distances.

In the old comparator [Andre] bought on eBay, the markings on the glass had faded to such a degree that the instrument was almost unusable. So he contacted [James] over at Clough42, who was able to create a near-perfect replacement screen by using a laser cutter, as shown in the video embedded below.

The first step was to replicate the screen’s markings in a CAD program. [James] explains the process in Fusion 360, demonstrating how you can generate all the different scales nearly automatically through the proper use of constraints, variables and patterns. He then transferred the drawing to Lightburn, which drives the laser cutter and etches the markings into a sheet of glass covered with CerMark, a marking solution that turns a deep black when heated by a laser.

After etching, the final step was to apply frosting to the glass to turn it into a projection screen. While there are several ways to achieve this, [James] went for a simple spray-based method that gave surprisingly good results. It took a few experiments to find out that etching the markings on the back of the glass and applying the frosting on that side as well gave the best combination of sharpness and durability.

[James]’s project shows that even delicate instruments with custom glass components can be repaired, if you just have the right tools. A similar strategy might also work for creating custom scales for analog meters, or even old radio dials. If you’re not familiar with laser cutters, have a look at our experiments with an Ortur model. Thanks for the tip, [poiuyt]!

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Laser Etching Stainless Steel With Mustard

[Brain] wanted to mark some scissors with his Ortur laser engraver. The problem? The laser won’t cut into the hard metal of the scissors. His solution? Smear the scissors with mustard. No kidding. We’ve heard of this before, and apparently, you can use vinegar, as well, but since the mustard is a paste it is easier to apply. You can see the result in the video, below.

In case you think you don’t need to watch because we’ve already told you the trick, you should know that [Brian] also goes into a lot of detail about preparing single line fonts to get a good result, among a few other tips like improvements to his air assist setup. On a laser cutter, the air assist blows away charred material leaving a clear field of view between the laser and the remaining uncut material. Using a proper air assist can really expand the capabilities of these inexpensive laser cutters — something we recently saw upgraded with a 3D-printed air assist nozzle.

You can buy a commercial marking solution called CerMark Black, but you probably already have mustard. If you are super cheap, you can probably pick up a packet next time you buy a burger somewhere. After all, you don’t need much. Although the video talks about the Ortur, this technique would work with any engraver. We’ve also heard you can do something similar with plaster and alcohol.

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Ultra-Polished, Handmade Settlers Of Catan Redux

[Fuzzy Wobble] and [Amy Wang]’s Deep Space Settlers project is a one-of-a-kind re-invention of the popular board game Settlers of Catan, and showcases the polished results that are possible with the fabrication tools and methods available in many workshops and hackerspaces today. We reached out to the makers for some of the fabrication details, which they were happy to share.

(For those of you who are familiar with the game, technically this is a remake and slight evolution of the Seafarers expansion to the base Settlers of Catan game. A few rule changes were made, but it is mostly a total remodel and redesign.)

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Laser Etching An IPhone 5

Laser Etched iPhone 5

CrashBangLabs in Regina recently got their hands on a laser cutter. The Full Spectrum cutter was donated by a local company, who were upgrading to a larger machine.

With no laser cutting experience, [Brett] decided that his first project would be laser engraving his iPhone 5. This is a bit of an ambitious first project, since the power and speed would have to be set correctly to get a good contrast level, and you only have one try to get it right. Also, using too much power might have turn the phone into a laser etched brick.

[Brett] used an older aluminium iPod for testing. Once the laser speed and power was dialed in, he loaded up the artwork for the real thing. The cutter did a pretty good job at etching the art, but as the etching started it became clear that an alignment error had occurred. Fortunately [Brett] decided to not interrupt the cutter, and ended up with a good looking phone, with a slight alignment issue.

After the break, check out a time lapse of the laser cutter doing its thing.

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Laser Etched PCB Production

Like most of us, [reonarudo] isn’t satisfied with the current methods of homebrew PCBs, so he put a laser on a reprap and started burning some boards.

The basic procedure is to cover a copper clad board with matte black spray paint. A laser was installed on the X carriage of the reprap. [reonarudo] used cad.py to convert the board files into g-code and fired up his laser. The quality of the boards is highly dependent on the accuracy of the laser so after working through some mechanical problems [reonarudo] managed to make some passable boards.

We’ve seen just about every manufacturing method imaginable applied to PCB production. Etch resist and toner transfer do the job and a reprap milling machine is pretty neat, but lasers are so much cooler. While it may not be perfect (yet), printing PCBs with a laser shows a lot of potential. Check out a video of [reonarudo]’s bot burning some copper after the break.

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DIY DS Lite RumblePak


This one’s been making the blog rounds, but it really fits us. Nintendo makes one, but this instructables tells you how to make your own for a DS lite. It uses a PIC 12F675 to read the input line and activate a vibration motor from an old nokia cell phone.

Oh, speaking of instructables, I forgot to mention that they finally picked a winner for their laser etching machine. Of course, if you lack the budget, you can make your own for $60.