Jul 28, 2017 | By Benedict

Maker Marcus Wu has built a 3D printed Curta calculator, a mechanical calculator that can make calculations with the turn of a handle. The device was originally developed by concentration camp survivor Curt Herzstark in the 1940s.

Most of us grew up with electronic calculators in school. But those bulky, solar-powered devices that could be flipped upside down to spell out rude words are being replaced by even more advanced models that will help the next generation of mathematicians tackle difficult problems.

Back in the early 20th century, however, you couldn’t simply go to the store and buy a calculator, let alone one that could solve brain-melting algebra problems. Primitive computers were only just being developed, and people had to find other ways to make difficult calculations.

One particularly impressive calculating device, the Curta mechanical calculator, was invented during the Second World War—and under extraordinary circumstances too.

Curt Herzstark, the Austrian inventor of the calculator, had a Jewish father, and was taken to the Buchenwald concentration camp in 1943. There, he was forced by his captors to continue developing the calculator so it could be given to Hitler as a gift following Germany’s eventual victory.

Of course, history went a little differently, and Herzstark was eventually freed, allowing him to finalize the Curta calculator on his own terms.

Herzstark brought his invention into production under his own name, and the mechanical cranking devices were popular right up until the birth of the electronic calculator in the 1970s.

Fascinated by the history of the Curta, present-day maker Marcus Wu recently designed a fully functional 3D printed version of the calculating device that other math aficionados can download from Thingiverse.

Wu was able to make his impressive 3D printed calculator after leafing through original engineering drawings for the Curta at Liechtenstein’s Museum Mura.

With notes from the factory drawings to hand, Wu designed his own calculator in Onshape, eventually generating 240 3D printable parts, including 100 unique designs. (The original Curta had around 600 components, but Wu found that he could combine many of these to simplify the design.)

The many 3D printed parts of Wu’s Curta are complemented by around 100 off-the-shelf parts, including ball bearings, springs, and screws.

After the 3D printable designs were sliced using Simplify3D, printing time for the calculator parts was around nine days. However, it took Wu several months to print, assemble, and test the entire thing. In total, the maker says it took a whole year from concept to finished item.

Luckily, Wu won’t have to spend an entire year fixing the device if it breaks: he says he can disassemble and reassemble the whole thing in a couple of hours.

And rather than leave the printed parts as they appeared from the printer, Wu also carried out a thorough paint job on the calculator. He used a Cricut cutting machine to cut out stencils for the numbers on the dials; paint masks are available on the device’s Thingiverse page along with the 3D printing files.

Wu’s 3D printed Curta calculator was printed at 3:1 scale and weighs 1357 grams (around 3 lbs).

The maker recently displayed his creation at the Charlotte Mini Maker Faire at the Discovery Place science museum in Charlotte, North Carolina. We’re sure attendees were as impressed as we are—after all, 3D printing + nostalgia = good times.



Posted in 3D Printing Application



Maybe you also like:


willi wrote at 7/28/2017 9:48:37 PM:


Leave a comment:

Your Name:


Subscribe us to

3ders.org Feeds 3ders.org twitter 3ders.org facebook   

About 3Ders.org

3Ders.org provides the latest news about 3D printing technology and 3D printers. We are now seven years old and have around 1.5 million unique visitors per month.

News Archive