The O.J. Adder

The O.J. Adder is a simple dial adder for adding British currency. It was made in about 1958-1961. It was invented by Oscar Styles Penn, a man who had quite an interesting life.
For more information about this and other machines in my collection, please visit my website:
www.jaapsch.net/mechcalc/
Picture sources:
Roadless Traction: www.classicmachinery.net/forum...
Machine gun corps: en.wikipedia.org/wiki/Machine...
Tank: en.wikipedia.org/wiki/Mark_V_...
Thanks to Stephen Freeborn for Oscar Penn's death notice.
www.youtube.com/@stephenfreeb...
0:00 Introduction
0:54 History
3:22 Addition
4:51 Clearing
5:26 Opening the case
5:49 Mechanism
7:00 Outro

[@TaramiBedona]

I've been watching a few of your videos a day for the past several weeks. I think I've worked my way through the entire back catalogue now. It has been a very interesting tour-of-sorts through the history of calculators, many thanks for making these.

[@TheOldMundane]

I did the same. I feel lucky to be part of the very small group that has found this treasure trove of relaxing and educational videos.

[@stephenfreeborn]

That is so cool. Its shifting accumulator windows seem unique. Amazing that he would make such a basic device so late in the game. What a great device.

[@jaapsch2]

Such shifting windows are used the Bonham & Schram calculator from 1905, and its remake The Calculator seen here: kzbin.info/www/bejne/g6TGe5aopd97pNE

[@stephenfreeborn]

Oh shoot, I have one of those too. How could I forget? Still OJ’s seem different somehow. The stylus is so cool too. The whole thing has a 1950’s modern aviation feel to it.

[@ChrisStaecker]

So clean! And with all the original accessories. Very nice- the stylus is great.

[@jaapsch2]

Sadly the instruction leaflet is missing, but I'm very happy to have the *original* box and the *original* stylus.

[@TheOldMundane]

I really appreciate the effort you've always put into getting clean audio. It seems to get better all the time. Would you mind sharing what microphone(s) and recording techniques you use?

[@jaapsch2]

I still simply use my camera's built-in microphone. It helps that this is a pretty quiet neighbourhood. The camera is a Panasonic Lumix DMC-TZ80 that I'm very happy with.

[@TheOldMundane]

@jaapsch2 thank you for the reply. It has a great sound.

[@MattMcIrvin]

British currency would become decimalized a decade after Penn died, so I suppose the lifetime of this device was limited even aside from electronics.

[@shko0729]

£157 4/8

[@stephenfreeborn]

What do you mean by this comment?

[@olegtarasovrodionov]

@@stephenfreeborn It's what adder showed here 3:23