Corona 5TE Typewriter

Becky and I were thinking about how to get the kids learning how to type. Of course we have our main computer, but it is often in use by adults. One of the main thing the kids have enjoyed doing on it so far has been to write text and print it out. The process of typing to printed output on the computer is not terribly direct, and there is the overhead of dealing with windows and desktop, etc. The idea of a typewriter came up: they can easily operate it themselves and they can have unfettered access. I was also moved by the idea of getting another functional antique machine into the house.



My limited memory of mechanical typewriters was that the experience of typing on one is significantly different than using a computer keyboard as far as key travel, cadence, and actuation force. I thought perhaps an electric typewriter could be more useful for training towards a computer keyboard, but with the aforementioned advantages of a typewriter. In retrospect, maybe a mechanical would have been better, but what I in fact bought was a Corona 5TE in pretty good shape from ebay.

The Corona 5TE was the first "portable" electric typewriter. It was manufactured in the 50's and early 60's as a relatively high end home machine. It is heavy and almost entirely made of metal, and is a semi-electric version of a mechanical model of the same vintage. I don't have much basis for comparison, but to me it has a wonderful typing action and is a pleasure to type with. When we received it, the basic action was ok, but the shift function did not fully translate to the alternate characters on the type, and after a short while the impression made by the type became very weak.

My plan all along was to visit Cambridge Typewriter (in Arlington), and hang out with the proprietor while he gave the machine a once over. Tom Furrier, the guy who runs the shop, was willing to accommodate my request to be present while he looked at the typewriter, but it took some months to work out an appointment time that would work for both of us. One day I left work a little early and brought the 5TE to his cozy shop on Mass. Ave.

I've passed the shop a million times, since I bike past it both directions when commuting to work. But this was the first time I went inside. Tom has a slew of beautiful and interesting typewriters on display.

It is worth a stop in just to appreciate the machines on the shelves.

There is also big pile of machines in cases waiting for service.

Tom sat down with the machine and typed through the characters.

Within minutes, Tom had identified the source of the shift problem, which was that the curved metal bracket which lifts and lowers the whole type set (the "shift basket") had broken loose of its mountings, and also the rubber which it used to be lined with had petrified and mostly fallen out. He removed the leftover mounting tab on the left side (the right side mounting tab and screw were missing entirely), and in 5 minutes of rooting around in the back had a replacement part with screws, harvested from another machine.

This one was lined with felt and fit perfectly. I found it amazing that he a) had the spare part, and b) could locate it almost immediately. I would be hard pressed to pull off something similar in my basement crammed full of junk, er I mean valuable technology artifacts.

Now Tom moved the machine in back to his work bench. I chuckled when I saw that he had worn a hole in the masonite lining the top of his steel bench.

He says the hole started tiny and gradually got bigger, and that for a while it looked like the continental united states. I told him he was lucky it hadn't looked like the virgin Mary, otherwise he would have had a big crowd wanting to see it!

Tom stripped the machine down and removed the casing pieces lightning fast, and installed the new shift basket. One of the two belts which run from the motor to the action was almost shredded, which explained the weak key strike issue.

Cleaning
The machine went into the small exhausted hood and was blown out thoroughly with compressed air. Then Tom went to work with paintbrushes and a can of his general clean/lube formulation, consisting of 5 parts mineral spirits to 1 part light machine oil (presumably from the jug of sewing machine oil next to the hood). Using a few different brushes, he scrubbed and cleaned all the internal parts.

This machine is pretty complicated, and surprisingly heavy. Given the mass of the machine, I thought maybe it would have a cast iron frame. But it is mainly comprised of many, many pieces of sheet steel. There are hundreds of parts in it, maybe even 1000? It is a dense forest of tiny stampings, little springs, linkages, pins, and miniscule flat head screws. Trying to figure out exactly how it works boggles the mind.

All the mechanisms and the way they function together displays an astounding ingenuity on the part of the design and manufacturing engineers responsible for the product. It has a baroque beauty made all the richer for the fact that with some minor repair and tune up it works extremely well 50 years or more after it was made. How many of the things I have made as an engineer will be able to do the same?

The motor runs continuously. It is linked by a rubber belt to a speed down pulley, which is in turn linked by belt to a ridged shaft running across the machine under the keyboard area (visible below behind the key trip levers and springs; it terminates in a bronze bushing at the right hand wall plate).

The intermediate speed pulley has a suspension which allows it to float around to compensate for machine settings and wear. When a key is pressed, a hook catches the spinning shaft and is thrown forward toward the platen.

Tom says the motor should not be left on for hours on end if possible; that it would very likely overheat, and that replacements are not easy to come by. I thought I should probably set up a timer box to power the motor through, such that you push a momentary button and it turns the motor on, but shuts it off automatically after 30 minutes.

Tom said one belt needs to be straight rubber to provide stretch, while the other needs to be a cord reinforced belt. These belts are no longer made, but Tom had a board hung on the wall with loads of harvested belts on it, from which he found a good match for the worn out belt in my machine. He says if you use reinforced belts for both, the machine is too clunky and that you need the stretchiness of the unreinforced belt.

This dial under the front of the keyboard area shifts the hex shaft and much of the hardware under the keyboard toward or away from the motor, which affects the key trip sensitivity.

After the innards were cleaned/oiled thoroughly, Tom went to work cleaning up the housing pieces and key caps. I think I remember he said he used diluted Krud Kutter for this purpose.

Next, he sanded down the platen; the rubber coated roller which the type strikes against. This machine has a fixed spacing between characters of 2.54mm, so over time the roller develops grooves under where the characters are hitting every time. Additionally, the previously grabby rubber surface becomes hard and glazed. Tom used 120 grit paper and a practiced technique to recondition the platen, and with about 15 minutes of work it was smooth and rubbery again.

Tom spent about 2 hours, mostly on my machine, and gamely tolerated my peppering him with questions while he worked. I really enjoy watching an expert doing what they are good at in many contexts, and Tom certainly fits in this category. This was an excellent way to spend an afternoon, and the Corona 5TE is now purring and ready to type its way through a few more decades of useful work.


Typewriter Renaissance
While I was in the shop for a short time on a weekday afternoon, Tom fielded several phone calls and there were two people who walked in the shop. I mentioned that he seemed awful busy. He agreed wholeheartedly and said business is bustling to such a degree he can scarcely keep up. Tom says things were looking rather grim for the typewriter business there for a time in the 2000's, but now things have picked up tremendously. Custom from other businesses using typewriters is down, but interest in older machines from younger people is through the roof.


Put to Service
The kids have been enjoying having the typewriter out on the dining room table. Child 1 was interested to see how it works.

They like to type some text on a page and color some accompanying pictures either before or after.

They like to show it off to their friends too, who usually think it is pretty cool.

Becky used it to type up blurbs to put on a family tree poster her and Child 1 did for their history club.

My mom typed up the clues for our felted wool fairy scavenger hunt at the girls' birthday party last month. Child 3 likes to type "B" over and over again.

A nice addition to the household.