With people freaking out today, I thought I’d make a post. About my small collection of mechanical calculators.

The Swifty One

Like with many things, a YouTube binge is what started this. Specifically Chris Staecker’s channel.

A late night eBay search, and few buck later, I had a battery-less calculator. The “SWIFT”.

This, quite frankly, sucks. You have to use a stylus to turn the wheels. They also only turn one way.

Adding is pretty simple, just turn the wheel, and it will carry as needed. Subtracting though, is a bit harder. You have basically overflow the register. The numbers in red help with that.

The Contex

This didn’t start off well. As in it didn’t come in one piece. I bought it from an Australian estate sale on eBay. And they only packaged it cardboard. It took a lot of work to glue back together. Thankfully, the mechanism was fine.

All you have to do to add numbers, is type them. That’s it. Don’t try to subtract on it though. You have to do that same overflow trick as on the “SWIFT”. But the Contex won’t help you.

You might be thinking, “How to I type a number bigger than 5‽”. Simple, you just hit a key more than once. Want a seven, type a four and five, simple.

If you want to see this one in action, Chris has a video on one that works identically to my unit.

The Chaddy

The last one I picked up was a Chadwick.

This one works pretty much just like the “SWIFT”. Just pull the wheels down to add. However, you don’t need the stylus, and you can subtract. Just move the wheels backwards. Simple.

Should I Buy One?

Most likely not. Each one of these needed maintenance. None of them worked out of the box. All of them needed lube, and the Contex needed a fair amount of glue. I also couldn’t take the Chadwick apart, so lubing it was a pain.

While they can look cool on a desk, using them also kinda sucks. Most people can do math better with a modern calculator or a spreadsheet. But then again, most hobbies aren’t practical; that would be boring.