Comptometer Model F Adding Machine Review / HowTo

The Comptometer Model F adding machine, made by Felt & Tarrant, from around 1917.
This is episode 11 of my video series about calculating devices.
"Methods of operating the Comptometer" PDF: faculty.fairfield.edu/cstaeck...
End song inspired by "Hotter Than a Molotov" by The Coup.
Chris Staecker webarea: faculty.fairfield.edu/cstaecker/

[@ct92404]

I have one of these, a model J, and I love it! It's fun just to play around with it. It's so amazing to me how a purely mechanical machine like this can do math calculations. Charles Babbage would be proud!

[@ChrisStaecker]

Yes- I didn't mention it but it can even do square roots if you know the algorithm.

[@jeffw1267]

For my Comptometer Model J (12 rows of keys!!) I bought some sewing machine oil (White Diamond) with an extendible tube. There's a red cap that goes on the end and I cut the end of it off with scissors so I can put the cap back on and squirt oil into all the tiny oil holes without any mess. I was also required to oil the base of each key and used just one drop on each key. The excess ran down into the machine housing. My Comptometer runs quieter now and I don't need to put as much pressure on the keys to operate it. The sewing machine oil cost just $6. Other oil is cheaper but doesn't work as well and can gum up the machine's works.

[@ChrisStaecker]

Wow- thanks for the tip. I've never actually oiled this machine using the holes. I've always used WD40 on my other machines but it sounds like this might be a better option. Thanks!

[@todaysknit2414]

@@ChrisStaecker Sewing machine oil works excellent for most old machines - it doesn't get sticky as quick a lot of modern synthetic stuff, it's made to stay slick.

[@ChristianGreyHawkins]

@@ChrisStaecker I know this comment is ancient, but I'm adding this for other people who see it. WD40 is a really poor lubricant, and over the course of a few years it literally turns into glue that can make it necessary to fully disassemble a delicate machine like this to get it working again. Zoom Spout brand bearing oil is generally regarded as the best easily purchased oil for mechanisms like this because it's pure and doesn't gum up nearly as bad as many other common oils.

[@someonespadre]

@@ChristianGreyHawkins yes I got some of that at a local sewing store, I was the only man in there.

[@flochartingham2333]

Simply elegant how subtraction is done using tens compliment by holding the highest place.

[@phoffa8306]

My friend just found one of these in a old warehouse in Chicago, it was going for scrap but it’s in perfect condition and seems to work so he saved it. Looks similar to this one in the video..glad I found some information on it cuz I don’t know nothing about it ..thanks for posting this video

[@tissuepaper9962]

*attend to the oiling!*

[@imrustyokay]

Hey, you might wanna put that secret video in the description, as annotations aren't working rn

[@vlasoslav2782]

I love your videos! I hope you get more viewers soon

[@ChrisStaecker]

Thanks! me too

[@mwichary]

Your videos are so good and hilarious. Hope you keep up the great work!!!

[@ChrisStaecker]

Thanks a lot!

[@ChrisStaecker]

Sorry- forgot to add the link. It's in the description now. Or just click it here: cstaecker.fairfield.edu/~cstaecker/files/machines/business_course_comptometer.pdf

[@mwichary]

Whoa, much appreciated!!!

[@bnewcol]

First off, God Bless you for showing/caring about these old machines and explaining them in easy to understand sentences. I am an outside Chicago native and have my father's Model F showing last patent date of 1920 and have always wondered how it worked. Now I know! Do you know where one can get a plastic cover for these? It gets so dusty and I would like to do a thorough cleaning and then cover it. Thank you in advance!

[@ChrisStaecker]

Thanks for watching! Old plastic dust covers are very hard/impossible to find in decent condition. In a pinch I would just use a plastic bag. If you know a grandma or someone with grandma skils, you could make a cloth one, like the one Dolores made for my machine here: kzbin.info/www/bejne/hKXUiHV7itWkqq8 Good luck!

[@bnewcol]

@@ChrisStaecker thank you!

[@francovasquez6889]

this is SO cool!

[@ChrisStaecker]

Thanks!

[@jhallenworld]

I'm going to make an electronic one- it has to be done. I'm thinking you could have a shift-key for subtract, and maybe more keys for multiply and divide. It could work like this: hold multiply, enter the number, then release the key to perform the operation on the register.

[@BokBarber]

They did make an electric Comptometer. It's just a bit rarer.

[@AlfredSpector]

Thanks for the video. Really good. Thanks you for it. Wonder if anyone knows how to replace the keys. I have one unit that works well but with many broken keys. And, another part-unit with lots of good keys. But, no idea how to switch them. Advice would be appreciated.

[@janiceyork4531]

I was hoping to find out some information for my father. He has a NCR Electric Adding Machine with the serial no. 154-5-9-EX and another no. 2-1028405. He says there is a brass plaque with NCR on the top of the machine. Can you help with any information?

[@ChrisStaecker]

Hi Janice- Sorry I don't know anything about NCR machines except that it stands for National Cash Register, though I guess you know that. Maybe try a google image search for - ncr adding machine - and see if you see any that look like yours. www.rechnerlexikon.de is good for finding info, but they don't seem to have much on NCR.

[@johneygd]

Am curious how this mechanism was all set together; i can imagine how really complicated it all is.

[@austinfernando8406]

there's a channel on youtube called 'mechanicalcomputing' kzbin.info shows the mechanisms of some calculators in detail including this one, very clear explanations and animations

[@andrewschrotenboer9445]

Dorr Felt’s mansion is in Saugatuck, MI and is worth a visit.

[@ChrisStaecker]

I don't know man- sounds like something a melon head would say.

[@SQUAREHEADSAM1912]

@@ChrisStaeckerlol

[@unspeakablevorn]

they say there are also Melonheads in the Shelton and Trumbull area.

[@ChrisStaecker]

Yes- I used to live in their neighborhood

[@der.Schtefan]

You should have kept your channel for these adding machine videos (they are great) and created a new channel for your educational videos.

[@ChrisStaecker]

Thinking about it…