Marking Klein Bottles with the Eggbot


We were lucky enough to have a visit from Cliff Stoll, geek celebrity and proprietor of Acme Klein Bottle. Acme is the finest source of Klein bottles on the internet.

Cliff came with an esoteric dilemma: how to engrave a glass Klein bottle. Acme Klein bottles are blown from borosilicate (Pyrex) glass, which has a low coefficient of thermal expansion, which means that the usual way of engraving a curved glass surface—laser engraving—doesn’t actually work.  With more common types of glass, you can use a laser engraver to etch anything you want into the surface. But with Pyrex, the surface simply melts unevenly rather than creating the microfractures that give an etched appearance.


So how would you etch the curved surface of a Klein bottle? It turns out, to our surprise, that it is remarkably easy to do it with an Ostrich Eggbot fitted with a diamond engraver attachment.

There was one complication, which is that a Klein bottle is a funny shaped object! In order to fixture the Klein bottle in the Eggbot, we made a couple of extra large couplers—much larger than the tiny pads normally used to hold the ends of an egg—with EVA foam rubber pads on their surfaces. The extra large couplers held the Klein bottle securely for rotation.



We did some initial tests with Sharpie and a medium sized Klein bottle to make sure our fixturing worked well.


And then we hooked up an engraver for a real test.


Here’s what the Klein bottle looked like after engraving. Not being particularly creative, we etched the word “KLEIN” into the side.  Because the Klein bottle is made from thick borosilicate glass, it takes engraving remarkably well. It is a much more sturdy object than the fragile Christmas ornaments that we have engraved in the past.


While we can’t imagine that it is a major market segment, the Eggbot seems to be ideal for working with Klein bottles (insomuch as anything can be perfect for working with a closed, non-orientable, boundary-free manifold). But regardless, it’s quite wonderful to find an unexpected application like this, where our little robot can solve a real-world problem that we had never even considered.

Using the Eggbot for Pottery

Eggbot Cups
We recently got the question,

Would the Ostrich Egg-bot allow me to “decorate” on a greenware pottery mug or bowl or similar shape?

The answer turns out to be yes. Garth, of Extreme Craft posted video of using his Original Eggbot for this. He first used a simple wood screw as a stylus.

He later used our diamond engraving tool, with great results. It is a use we hadn’t anticipated!

Twitter controlled Eggbotted LED Ornaments

AJ Fisher posted an incredibly thorough write-up about his Twitter/Raspberry Pi/Arduino controlled LED lit Eggbot decorated Christmas tree ornaments. Each ornament would light up when twitter keywords represented by their icons were being used.

In the words of a friend of ours, “It makes me feel as though there are people all over the world celebrating with their family and friends just like we are, and you’ve brought them all into the room with us” – and if that’s not what doing this sort of technology is all about then I don’t know what is.

The article includes techniques he used, links to his code, source vector art, and so much more.

Vector engraved stipples

Laser-etched Hoan Bridge

Over at rasterweb, Pete has been playing with StippleGen2 to create artwork with the laser engraver at the Milwaukee Makerspace.

Laser-etched Hoan Bridge

StippleGen’s output consists of lots of tiny overlapping circles and this piece was made by using vector engraving, where the laser traces out each circle individually. In some places, the lasered marks overlap many times, leading to a new and unusual surface texture. In the closeup above you can see the ridges and valleys formed by the overlapped engraved areas. Go check out his article for the rest of the story about the project!

Hershey Text: An Inkscape extension for engraving fonts


Hershey Text is an Inkscape extension that can render a line of text in one of several stroke-based “engraving” fonts. This extension solves a persistent problem, and one which we have come across in many different contexts: How to easily create simple and readable vector representations of text.

Quick start: Download and install the EggBot extensions for Inkscape, which now include Hershey Text. Much more information follows.

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