Corona 4 "Goldie" — Boatworks

This is my second Corona 4 typewriter but this one had certainly much harsher life.

When it came to me nothing was working. Carriage was seised, slugs could not reach the platen, draw band broken and wrinkled around intestines. Quite obviously the mechanism was clogged, the usual suspect is WD40 or similar.

I removed the platen & whereabouts and soaked the mechanism in paint thinner. After a while, a careful attempt to release the carriage was successful. I left the machine to dry a bit before moving further.

Before moving further I needed new feet. This machine is so low that without feet the mechanism collides with table.

Original rubber feet were mostly gone. I managed to remove one of them in almost intact state and use it to make my copies. I use synthetic rubber, sold in Biltema as “genomföringar” on electrical department. Three components form one foot, no glue needed - friction fit is holding them tight.

After removing whatever I could from the main frame I moved outside to clean the machine.

Since the mechanism was so clogged I had to rinse it several times. For the first few baths - and for the segment - I used just pure paint thinner. It happened to be International No1 which smells like hell.

Last rinsing was with low-aromatic white spirit with added some engine oil, my usual “typewriter soup”. That gets rid of ugly smell of previous baths.

Between each bath the mechanism was thoroughly blown through with compressed air.

Clean and almost dry the machine is moved back to my workshop.

I removed spring engine and inspected the spring. Removed rests of the old draw band and installed new. One does not need to be very exact with the length: as long as it is long enough to be at least partly wound on the drum when the carriage is in rightmost position. I tend to make them a bit longer so I have a few wounds left.

I wound the spring and attached the new band.
The machine came to life!

I started troubleshooting all remaining issues. Most obvious were paper feed rollers. Big, back rollers were in OK shape, only a few flat spots on one of them. The front roller was far gone and needed replacement.

I sanded back rollers on “poor man’s lathe” (drill machine & sandpaper) to remove irregularities. Front roller got cleaned from old rubber. While at the dirty job I sanded oxidised rubber from the platen, too.

Platen is hard as plastic but not cracked anywhere. I will keep it like that until I find a reliable place in Europe to do proper re-coating. Front roller will be covered with grippy and soft silicone tubing.

Installed on paper bail, mounted already on the carriage. Looks good!

I carried on troubleshooting.

Right hand side carriage release lever was not releasing the escapement properly. I found the problem to be bent stop tab. I formed it back to proper shape and life became good again.

Next problem was line advance ratchet. Single spacing worked fine but double spacing did not engage enough of the toothed wheel. I found the problem to be bent (again?) the bottom guiding surface for the ratchet arm.

I formed it so that the bottom tab was gliding effortlessly above it thus gaining enough reach to grab one more tooth on the wheel. Problem solved.

After dry fitting the platten I noticed that something is colliding with its surface. Tell-tale mark pointed towards right-hand support for the front paper roller. Yep - this guy was bent, too!

I formed it back to shape, hopefully fixing also the problem with uneven paper pressure.

Before putting the platen back I wanted to fix the clutch. It also was blocked by dirt or years of not being used so that it was all the time engaged. The mechanism is inside the platen’s core. I closed one end of the platen and filled the core with “typewriter soup”, in hope that it will unfreeze the clutch.

I left it for half an hour and poured out the “soup”. Yes, it did unlock the clutch but I also noticed that internal leaf spring is loose. Probably broken. I was not sure how to remove the ratchet wheel without destroying the wooden core so I left it for now. With this mechanism non functioning the platen has no “free wheel” function. I can live with that until I found a way to disassembly this part.

Part of this mechanism - movable left-hand knob’s conical axis - was frozen in the knob. Penetrating oil and hard fist slap has freed this part.

I cleaned it from dried oil, oiled and the platen was ready for re-installation.

Then came my least favourite job: cleaning the key faces. This machine has thin celluloid “glass” on top of paper cards. I usually clean them in situ as soft, brass tabs holding rings are fragile and I don’t have the ring tool to safely press them out. I wish they did it as Blickensderfer did - with spring rings.

My current way of working is to wipe them with non-diluted Ajax to soften the gunk. One has to be careful to not flood them - if the liquid goes below the “glass” the paper card will absorb it and become distorted. After doing 3-4 keys in a row I wipe them dry and work out the dirt from below the ring with wooden tooth-pick.

As a last step I wipe all keys with isopropanol.

After assembling the machine I tried all keys. Some were binding but it was not the dirt left in the segment. They were bent! Upon entering the guide they were binding on one or the other side of it.

It is hard to see but easy to feel which side is binding - just drive the type slug by hand towards the platen. It should enter the guide hardly touching it. Tolerances here are crucial for even print and seamless operation.

I patiently re-formed types which were binding. It is a tedious, delicate and repetitive process. Often one finds that the slug is no longer binding but the imprint is too low or too high or the slug will not sit back in its resting position due to collision with its neighbours. Sometimes neighbours also need to be corrected resulting in new binds.

After long time I managed to get all of them aligned to my satisfaction. Upon very close inspection some letters still do not print perfectly but I left it “as is” and decided to check if it is visible in print.

Final step was to install fresh ribbon. I got lucky with this machine that both original spools are in place and capping hats are not missing either! Spools use spring clams as ribbon holding mechanism - unlike most other machines where spools have hooks which puncture through the ribbon. Clamp mechanism is more difficult to put the ribbon on but otherwise very pleasant and straightforward. Same structure is used on Oliver machines.

Feeding the ribbon into vibrator is straight forward. Once done I rolled in a piece of paper, noticing that rollers do their job with authority and the page emerges straight and firm.
I sat comfortably and began to type.

Typing feeling is snappy and responsive. All worked fine even with quick typing. I used double paper to improve print on this otherwise very hard platen. The result is fine, typeface has its charm of old style font, almost serif style - a few letters have serif features.

Lastly I waxed the frame and panels with Fulgentine. Black became even darker and shine, many scratches disappeared and glossy finish came back.

Some “honest patina” is, of course, visible and I see it as an advantage. This machine is very old and well used! In current state it can still be used for many years to come.

Pleased with the result I took the machine for photo session.

Charming, little typer. In many eyes one of the sexiest machines. I concur. Same type of charm as Underwood 5 although totally different beast.

For comparison I took my other Corona 4 and studied both machines side by side.

Sitting side by side, with their antennas erected (no WiFi thou!) they are exactly the same. Only small differences like paper fingers or how linkage is drawn on the underside.