Hey! I have one of these. Fully functional Model J. Found it in a Goodwill for 8 dollars. Serial Number puts it at a 1926 production date. And it was painted Olive Green, which means that sometime in the mid-50s someone sent it back to the factory for refurbishment. Every model refurbished in the 50s got repainted at the factory to the new standard color of the recently released electric machines.
In 1972 I worked for a precast concrete company in an estimating department. During the day quotes would be put together manually and then when complete placed in pigeon holes. I would then collect an armful and take them to the ground floor. On the ground floor was a very large room filled with ladies all in tidy little lines at single desks carrying out the calculations in the estimates using types of these machines. They were then returned to the main office and signed off by the senior estimator and director. We had two calculators and two telephones in an office of twenty plus estimators. The drawing office of forty staff had three telephones and used slide rules. Nobody had a calculator or trusted them. The job of 'Comptometer' was not just a machine it was a skilled job and the sight of dozens and dozens of ladies all punching in the numbers and pulling down the lever was quite mesmorising. ... and there wasn't a computer to be found anywhere. The job of calculating was that of these ladies and so getting things right could mean whether a high rise block of flats fell down or not. In the sixties one did.
The speed of the comptometer vs the calculator reminds me of the speed of trained accountants using abacuses, pushing multiple beads at once being similar to pressing the multiple keys at once to move entire numbers around.
I used a comptometer in the 1970's. I would take home a machine and inventory from a company who was contracted to calculate the inventory for major stores in New York, J. C. Penney's, Sears and etc. Earned lots of extra $ at home at the dining room table. The machines are easy and accurate. Oh how I miss those days.
I'm lucky enough to have a 12-column version of this machine. If you have one it is important to oil it properly. I use sewing machine oil and it has to be applied through the key slots as well as the oil holes. If it's oiled properly it will never need repair.
Nice video. I feel the same way about the Comptometer. I only properly started my calculator collection and website after I got one. The Comptometer seemed to be somewhat dismissed amongst collectors for being too basic, and I hoped my site would redress the balance a little bit, especially through making available scanned versions of all the documents and manuals I could find. The manual you used is one from my collection.
Cool antique device, but I got hella confused with that very detailed but very complex usage instruction 😟 I’d like to see the internals of this beast.
This video inspired me to get my own Comptometer which also turned out to be a Model H. After a little bit of practice, it's surprisingly usable for the basic 4 functions. Even division really isn't that bad once you know the rules. I won't say it's better than a regular 4 function digital calculator, but it's certainly more interesting than once of those and perfectly usable, especially for tallying up totals. It's also a marvel when you open up the case. It's amazing what they were able to accomplish with just gears, springs and stamped steel.
I graduated high school in 1972. In my sophomore year I studied advanced business machines. If you divided million by one on one of these calculating machines it would click 1,000,000 probably burning the machine up. Something I always tried to get away with on a Friday when the teacher was locking up the classroom but she always caught me. The following year a student brought one of the first electronic handheld calculators to school. I divided million by one and the screen went away for about five seconds and came back with the answer. In that moment I realized everything I had learned was now obsolete.
Blimey! I have a 1914 Comptometer and I know how to use it. I have to say you just gave the most complicated explanation of how to us one I have ever seen!
My grandma went to comptometer school at the insistence of her father. He believed his daughters should have some useful post school education. It landed her a job before the war. She then bucked rivets on B29's for WWII.
I have a comptometer! It's a different model than yours -- the digits aren't differently colored, and there's two fewer of them -- based on the serial number, I'm guessing mine's a model J? Yours is also in much nicer condition, mine's missing a few keycaps, and has some mismatched replacements on others. It was my grandmother's -- she was a calculator girl in the engineering department at General Dynamics (now Lockheed Martin). She said they used to hold races on them, and she usually came out on top. I never knew what those little levers above the register were for, nor did I ever notice that the keytops alternated shape by row! Very cool to learn more about this thing that's been around my whole life. :D
I've used one or at least something very similar Unfortunately it wasn't fully in base 10! First few registers in base 10 then 1 in base 20 (0-19)then 1 in base 12 (0-11) and the last one in base 4 (labelled - ,1/4,1/2, 3/4)
Neat, very neat. Also i was a little confused by 9's compliment initially but looked it up online, maths is not my strong suit but i found this really interesting, thank you.
Mechanical calculation of sums with such a large keyboard of course is easier to be fast - you are limited by how fast you can enter the numbers. And addition (and even simple multiplications ) depend on your input the most. I mean examples like "1+2" show this quite clearly - for basically anybody it would take far too long to enter this in any sort of calculator to be worth it - you know the result. "15+17" is a bit slower, but still just pressing those 5 keys on a calculator in sequence takes longer than doing it in your head. But here the Comptometer starts to shine - when you are trained with it you will basically just have to press something 2 times as you press the whole number at once. Accounting any many other tasks often involve just simply adding up many numbers - when you can easily enter 2 or more numbers per second, trained can be significantly faster. of course with modern calculators there are also people that can enter 20+ digits a second too, but takes longer to get to that point. But nowadays this has become mostly obsolete cause there is little reason to print and re-enter the numbers. You use a computer. If you have a long list of numbers to sum up you likely already have it in a table-form and opened with a table-manipulation software. And if not already setup to do the calculations beforehand doing so still requires little time. Adding up tens or thousands o numbers takes virtually the same time. And for getting data from the real world - USB callipers are a thing. No matter how fast you are: using them for data acquisition is faster than writing down the numbers or directly adding stuff up as the whole number can be taken with the press of a single button.
Such an impressive machine! I really only lived through the tail end of mechanical calculator era, and I continued to use slide rule simply because I cannot afford scientific calculator. But I never seen something this impressive, maybe they were hidden from regular students but even science department only had desk adding machines and some small mechanical calculators that printed on a paper tape. There were computers, of course, but not readily available, only in the science lab, connected to equipment. At least they were IBM 5150s.
Amazing how this still is fully operational after 100 years, however our modern devices which are far more technically advanced will likely last a tiny fraction of that amount.
I was hoping for you to do a teardown of the internals like you usually do. First, this thing obviously isn't broken like everything else you have, but also, I was really hoping to see how it was actually laid out inside.
You should watch someone taking inventory with a 10 key adding machine on their hip. I can believe that someone good a ten key can be just as fast as someone using one of these and possibly faster. 125-200 keys per minute (~8000-12000 keys per hour). I have seen this being done and they were amazingly fast! I'm no slouch, once I get my hand limbered up, but I don't think I can do more than 7,000 and I'd make a ton of mistakes along the way.
I would love to get an overview on how the mechanisms work together. These old machines are virtual treasure troves of patents that have become public domain due to patents being time limited. The technology involved in the mechanical engineering of these devices isn't as antiquated as it may seem when you consider the relatively new and growing fields of robotics and mechatronics.
Great machine, great video. Personally, I would need to actually do maybe 3 multiplication examples - show me the problem, and the keys to press. After completing/practicing them, then the rules read out loud/explained to me begin to make sense. Until then they don't. So this machine is hard to learn, easy to use after that. Fun video. thanks!
also, on a highly technical video (relatively, as compared to all the cute puppy videos), the music (such as on the Blip video) was not missed. Thanks.
I've got one of these! Except it has 12 rows of keys...it still sits on my old oak desk. It gets uses every now and then. Even for balancing my checkbook.
Yeah, but the Comptometer doesn’t use Nixie Tubes. ;-) Regarding the keyboard suddenly locking up: IBM keypunch machines did that as well. If there was not a card positioned in the punch station, the keys would not go down. Also, only one key would go down at a time. This was all enforced mechanically; the guts of the keyboard were a nightmare. In high school, I used a Friden Calculator which is sort of like a Comptometer but the readout was on a carriage, like a typewriter, so you shifted that instead of moving your hand across the keyboard for multiplication.
I will have to study these operations. It seems they might be useful for doing arithmetic with logic circuits. I’m really curious about the square root operation.
I just made a video about how to extract a square root using a Comptometer. I am not sure whether my method is period-authentic, but I believe that it easily *could* have been used in the old days. I wonder: in the old days, were the Comptometer operators encouraged to be resourceful in devising methods to perform calculations on their machines? Or were they simply instructed not to worry their pretty little heads about such things, and to instead simply (and blindly) follow whatever methods they were taught? From what I have read, I suspect the latter to have been more likely.
I received a model B for Christmas and I'm excited to play with it. But the handle on my clearing mechanism is bent. I'm afraid to bend it back for fear of snapping. I wonder if you have any suggestions on how to fix it - or how to find a replacement handle.
if you still have it, depending on how bent it is and how thick it is, you may have to go as far as stripping the paint and disassembling it and heating it up with a torch or fire over and then bending it. If you were to bend it cold, the metal where its bent gets more and more brittle which can cause it to snap, it's also a lot harder to do. Heating it up makes the structure relax so it wont get work hardened as much. If it's just warped then you can heat it up and clamp it between two boards
What a con. I looked up Skilshare for Comptometer courses and they don't even have one! I've repaired and refurbished several and are now in a couple of local (local to England) computer museums.
Why did all old innovative inventions have the absolute worst names? It's like they could build a mechanical calculator, but couldn't make words whatsoever. Say it with me...cal-cu-la-tor. Why not even compumeter ,or computer. Where tf does the "tom" even come from? With that logic, it's a comtomputor, or a calctomulator. Uhmmm no. Let's not, ever again.
