Skip Counting Wheel
I've updated the parts and the Instructable. There is now an option for splitting the step drum which reduces the minimum print volume to 160x160x170mm. That should allow more people to be able to build the Curta.
I used a triple c-bot I built (http://openbuilds.org/builds/triple-c-bot.1757/) to print the parts. The filament was 3D Mars from Amazon (http://amzn.to/2evDRLa)
It is a long build and he is a busy guy, but it hasn't gone unnoticed: https://twitter.com/donttrythis/status/730590977786662912More on that soon
Wow! Curta for $10 -- that's the dream :)
Awesome compliment, Thanks! I definitely have some detailed maker projects in mind for the future. My next one, though is software (and possibly more complex than the Curta) for a business I want to start... but it is oriented towards makers.
Thanks! The engineering was done by the guy who invented the Curta (Curt Herzstark). I did the CAD work from the original engineering drawings at nominal dimensions and 1:1 scale. Then I scaled it up and added tolerances for 3D printing. The CAD work took about a month to get at 1:1 scale. A couple weeks after that I had a scaled up copy with tolerances added in. I learned CAD along the way... There are a few parts I would build differently now.
That's a cool story! I learned the basics of using it on YouTube and the rest I figured out through vcalc.net where the manual is posted (http://www.vcalc.net/cu.htm#manual).
I've built two Curtas. The first one was just to build one for myself. I haven't painted that one. The second one was to help put together all the documentation I needed for my build manual, assembly video, and this instructable as I went along and to establish a procedure for painting it. The first one is still not painted and needs a few parts reprinted (I dropped it -- that was a terrible crunching sound, btw).I have something special in the works for the fully complete and painted one -- that'll be announced later :)
The calculator's basic operations are addition and subtraction (subtraction is actually done via 10's compliment addition similar to how a computer does subtraction via 2's compliment addition in binary). From there, multiplication can be done via repeated addition and division can be done by repeated subtraction. Multiple digit multiplication and subtraction is aided by being able to rotate the upper carriage which is the base 10 equivalent of a shift operation on a computer -- basically multiplying the input by a power of 10 as it adds it to the result. Those who are good at using it can also calculate squares and roots among other things (though roots are not as easy as simply using the square root operator at the press of a button).
Thanks! And for anyone / everyone reading, I think the biggest thanks I could get are pictures of completed builds. Here or on thingiverse (or both).
1) PLA. It has better printability and rigidity compared to the others.2) The height is due to the step drum and main axle. I can design a version that separates the largest portion from the step drum.3) None of the parts are designed to have the numbers and letters printed into them so multiple materials would not help with color without redesigning those parts. Soluble supports may help, but I did not need them and it does add to the expenses of the build.
Etching PCBs With Press'n'Peel
Lesson 2: Drawing Technique
Design Sketching Class
Build a 3D Printed Curta Ca...View Instructable »
Writing an Instructable and Adding Photos
Publishing an Instructable
Welcome to Writing an Instructable
How to Write an Instructable
The Universal Multipurpose Workbench