Restoring yet another antique Teletype machine

[oldskoolpunk]

I'm the guy behind the Aetheric Message Machine Company. We set up a working telegraph office at steampunk conventions. Last weekend, I acquired another Teletype machine to save it from being junked. Here, I'm going to post, in some detail, the process of restoring it.


Here's the machine as it was offered to me.

The previous owner was disposing of the estate of a late radio ham, and had a shed full of various equipments.

[oldskoolpunk]

This is a Teletype Model 15, first manufactured in 1930, and designed by Howard Krum. This was the workhorse of newspaper wire services well into the 1960s. Hundreds of thousands of these machines were made, they were built to last, and many still exist. Full documentation is available, which is a big help.

This machine is dirty, slightly rusted, and missing a few parts. There's no serious damage. The motor runs, and the selector magnet works. Those are the only two electrical parts. So let's get started.

The first step was to separate the base, typing unit, and keyboard.  The base has the motor and wiring. We put that aside for now. The keyboard and typing unit get an overnight soak in Simple Green and distilled water. This gets rid of most of the old lubricants. There's still a white residue on many parts, but that comes off with compressed air, Scotchbrite, and cotton swabs, and hours of work.

The next step is to check to see that all parts will at least move.  Many of the typebars stick, the main shaft clutches are stuck, and the carriage return dashpot won't move at all.


The carriage return dashpot. All this just to give the carriage return a soft landing.

Providing some kind of soft stop for the typewriter carriage seems simple, right? All you need is a rubber block. But this is 1930 technology. Synthetic rubber hadn't been invented yet. Natural rubber dries out and cracks, doesn't behave well around oil, and doesn't have consistent properties. So when the carriage returns, powered by a spring, a pin on the carriage hits the bell crank (the end of which is at the right), which pushes on the piston shaft, which drives the piston inside the cylinder, which forces air out through an adjustable needle valve. The piston has a leather disc, with a large washer on one side of the disc and a slightly smaller one on the other. So the leather disc folds up slightly on the pull stroke, letting air go by, but provides a tight seal on the push stroke.

Anyway, the piston won't move at all. Pushing hard doesn't help. Fortunately, everything in these machines comes apart easily. So I take out the dashpot assembly and disassemble it. I get to the point where I have the cylinder end and the piston shaft, and nothing else, and they're still stuck. Taps with a rubber mallet don't help. Finally I have to use penetrating oil, wait a few hours, clamp the piston shaft in a vise with rubber jaws, and using a big pair of pliers, rotate the cylinder end. The piston moves a little, and I'm able to get it out.

What's wrong? There's a black tarrish material on the piston rod. Somebody used the wrong lubricant. (The official lubricant was whale-oil based; I use 0-20W synthetic motor oil. Using something that evaporates to a solid residue is lame.) Since the piston is a tight fit, the soak in Simple Green didn't get it out. A little work with Scotchbrite, and the piston rod and cylinder end are nice and shiny, and everything moves smoothly. While I have the dashpot apart, I give the leather disk a quick soak in Hydrophane leather conditioner, a silicone-based oil used for horse tack. The dashpot goes back together, gets a light oiling, and now moves smoothly.

[oldskoolpunk]

Gears This is steampunk, so there should be pictures of gears.

This is a view of the typing unit from the bottom. That's the main shaft of the Teletype. Here, it's dry, unoiled and ungreased after cleaning. The main shaft is hollow, with a felt wick inside and an oil plug at the end. When it's filled with oil, oil comes out through small holes in the shaft to oil the cams and clutches on the shaft.

The oil plug is missing.

So we consult the parts manual, and find that the missing part is "Oil Plug, Teletype Part #74101". Last year, a two-suitcase set of Teletype repair parts appeared on eBay, and I bought it rather cheaply.


We have spare parts!


Including Part #74101


The oil plug goes here.

We're still missing the leather washer (Part #74100) which goes with the plug, but a Neoprene washer will work. (We have oil-resistant rubber today! Science marches on!) So soon I'll be able to oil up the machine without a big oil leak. A bit more cleaning first, though.

[oldskoolpunk]

Up in the typebar area, there's a lot of surface corrosion. But it's just dirt on the surface, and comes off easily with cotton swabs.


Yes, I have to go in there with cotton swabs, little brushes, and compressed air.
What you're looking at, incidentally, is the mechanism which decodes 5 bits into one of 32 typebars. Those 5 curved rails have slots which encode bit combinations to typebars. For any position of the 5 typebars, one of the levers will be above five open slots and will drop down. A hook on the bottom side of the lever engages an oscillating bail which pulls the lever, driving the typebar up to the paper. This is a mechanical binary digital device.


After more cleaning, it's better, but not good enough. I need new brass-bristled brushes. More cotton swabs. 

Another problem: there's a missing screw.

Note open hole near bottom center

It's not just missing, it's broken off. The broken screw is removed and replaced. In a later stage, the arm it supports, which has a stack of shims under it, may need further adjustment. But that lies ahead.

[Drew P]

*crunch, crunch, munch, munch* (popcorn) 

[Maets]

*crunch, crunch, munch, munch* (popcorn) 

What he said!

Thanks for posting.  Looking forward to see how it progresses.

[akumabito]

There is a Creed Model 3 for sale about a hundred miles from here. It's in working order, though I bet it could use some TLC. I know too little about these machines to make a project out of it myself though. Plus, I don't know where one would get gummed paper tape these days.. If any of the Dutch members are interested: http://link.marktplaats.nl/m833601047

[oldskoolpunk]

There is a Creed Model 3 for sale about a hundred miles from here. It's in working order, though I bet it could use some TLC. I know too little about these machines to make a project out of it myself though. Plus, I don't know where one would get gummed paper tape these days.. If any of the Dutch members are interested: http://link.marktplaats.nl/m833601047

That's a good price, and it looks like it's in good condition. Model 3 Creed machines are relatively rare. That's a 1927 design, used for the UK GPO's inland telegram service for several decades. (Creed was the main UK teleprinter company. Other European makers were Siemens (Germany) and Olivetti (Italy). Lorenz (Germany) manufactured the designs of Teletype from the US.)

Creed went on to convert that mechanism into a page printer, the Model 7, in 1931, resulting in a rather wide moving carriage machine. There's a lot of variation in code and speed for those machines; if you're lucky, it's a later ITA2  model (3A or 3B) at 45.45 baud, which will interoperate with Teletypes. Early models were Murray code at 49 baud, (3X model which means you'll have to program an Arduino or something to drive it.

I'm not sure what the Creed parts situation is. The Teletype parts situation is relatively good; enough people have supplies of parts that most machines can be fixed.

What tape width does that Creed machine need? I have 3/8" (8mm) tape available. I had it made up,  ungummed, and the supplier (Fujian Ningde Captain Industrial Co., Ltd.) can make gummed tape in custom widths, if you order at least 500 rolls. Gummed tape is for pasting down on telegram blanks for later delivery. Ungummed tape is for instant messaging, where the machine and recipient are at the same place.

[oldskoolpunk]

Today, fiddly bits. Ordered a neoprene washer (Seastrom 5613-108-62, WASHER, FLAT, ROUND, NEOPRENE, $1.6243 ea) to replace the missing leather washer. More cleaning. Got some grunge off the rubber platen. Straightened a bent typebar guide.  All typebars now seem to move properly. The main shaft clutches are still stuck, though. That's to be expected; I haven't done the oiling yet.  I want to do all possible typing unit cleaning with the machine "dry". There are over 600 oiling points, and detailed instructions.

Cleaned the base, which is a hulking big casting which supports everything else. I thought I'd have to repaint it, but the gloss black paint was intact under the grease and dirt. Replaced oversize 20A fuse (!) with proper 3 2/10 amp fuse. Noticed that the power cord is 2-prong, and I will upgrade it to a 3-prong plug and ground the frame. Also, all cords will get strain relief. The sheet metal bottom cover for the base is missing; it's not essential, but I'll try to get one, or make one.

The keyboard will get some attention next.

This is all preparation before first power on.

[Mr. Boltneck]

Thank you for posting this. It's an amazing machine.

[Michael Farley]

One the one hand I can't wait to see the finished machine up and running again. But on the the other hand your WIP updates are fascinating to read so I don't want you to finish too soon.

[Plutus Sar]

I'm a ham (amateur) radio operator, and I see fellow hams trying to give these type of machines away a lot.  In fact, I've seen these left sitting at the end of the day at several "hamfests" (amateur radio flea markets) for the trash to haul away.  They are big, and heavy, but is someone is interested I can keep an eye open.  Most likely need to be in the U.S., I'd hate to imagine shipping one of these!

[akumabito]

There is a Creed Model 3 for sale about a hundred miles from here. It's in working order, though I bet it could use some TLC. I know too little about these machines to make a project out of it myself though. Plus, I don't know where one would get gummed paper tape these days.. If any of the Dutch members are interested: http://link.marktplaats.nl/m833601047

That's a good price, and it looks like it's in good condition. Model 3 Creed machines are relatively rare. That's a 1927 design, used for the UK GPO's inland telegram service for several decades. (Creed was the main UK teleprinter company. Other European makers were Siemens (Germany) and Olivetti (Italy). Lorenz (Germany) manufactured the designs of Teletype from the US.)

Creed went on to convert that mechanism into a page printer, the Model 7, in 1931, resulting in a rather wide moving carriage machine. There's a lot of variation in code and speed for those machines; if you're lucky, it's a later ITA2  model (3A or 3B) at 45.45 baud, which will interoperate with Teletypes. Early models were Murray code at 49 baud, (3X model which means you'll have to program an Arduino or something to drive it.

I'm not sure what the Creed parts situation is. The Teletype parts situation is relatively good; enough people have supplies of parts that most machines can be fixed.

What tape width does that Creed machine need? I have 3/8" (8mm) tape available. I had it made up,  ungummed, and the supplier (Fujian Ningde Captain Industrial Co., Ltd.) can make gummed tape in custom widths, if you order at least 500 rolls. Gummed tape is for pasting down on telegram blanks for later delivery. Ungummed tape is for instant messaging, where the machine and recipient are at the same place.

Thanks for the info! In the add it says it works at 45 baud. I've sent the seller a message asking for the specific model designation. Good to know the gummed paper is just for sticking it to sheets of paper.. I feared it had something to do with how the machine operates. Still, it's pretty darn hard to find 3/8 paper tape. Even if I got the machine to work, I doubt I'll ever need (or can afford) 500 rolls of the stuff..

Do any of the slightly newer models use standard-sized paper? A teletype machine that would accept standard A4 sized paper would be sweet..

[oldskoolpunk]

Thanks for the info! In the ad it says it works at 45 baud. I've sent the seller a message asking for the specific model designation. Good to know the gummed paper is just for sticking it to sheets of paper.. I feared it had something to do with how the machine operates. Still, it's pretty darn hard to find 3/8 paper tape.

I sell 5/16" paper tape for tape printers, since I had more made than I can use.  $75 for 15 spools. I'm supplying a number of museums and collectors. Western Union used 5/16" (8mm), AT&T used 3/8". Don't know what Creed used. You can put 5/16" tape in a 3/8" machine, and it will feed, but the letters will drift a bit vertically as the tape moves around.

Do any of the slightly newer models use standard-sized paper? A teletype machine that would accept standard A4 sized paper would be sweet..

The page printers take roll or fanfold paper. Teletype rolls are still available commercially, for about $5/roll. Sometimes cases of the old yellow paper show up on eBay.


Steampunked tape printer.

Here's my steampunked tape printer, the printing unit from a Model 14 Teletype in a brass and glass box. It usually sits in my living room. It's been to about five West Coast steampunk conventions. It's connected to a Reuters news feed, and it starts up whenever a new story comes in.  The printed tape falls into a basket, and visitors can read the news. It's a pleasant piece of steampunk ambiance.

[MWBailey]

Do you restore typewriters as well?

[oldskoolpunk]

Do you restore typewriters as well?

No; don't have the parts.

Today, I'm unjamming the selector clutch release mechanism.  



This is the part of the mechanism which synchronizes the machine with the incoming bit stream. When the machine is between characters and the incoming signal changes from MARK to SPACE (or, as we'd say today, 1 to 0) the selector magnet arm (not shown) pushes, very lightly, on the trip plunger 7007, which pushes on bell crank 6850, which pushes on trip latch 6830, which releases stop lever 6909, which allows the main shaft and clutch (not shown) to rotate, starting a print cycle. This is one of the more delicate parts of the machine, and it's stuck so hard it won't move at all. So I have to consult the manual and plan out how to get in there and un-stick it.

The stop lever 6909, which is supposed to swing freely, is frozen to the shoulder screw 6799. Probably because the wrong lubricant was used, which was the problem at the carriage return dashpot. I'm starting to suspect this problem will recur at other places where the cleaning solution couldn't reach.  I'm going to have to remove the spring 7603 with a spring hook, remove the shoulder screw, stop lever, and nut 3598, clean everything, and reassemble.

(Update: did all that, and now that part works.)

At Clockwork Alchemy 2014, the tape printer (the one shown above with the wooden base) failed and started printing junk because nut 3598 had come loose. I was able to fix that in a few minutes, but it shouldn't have happened. Different versions of the manual show that part with a lockwasher, without a lockwasher, and, in later manuals, with a lock nut.  There's a service bulletin; I should add a lockwasher below nut 3598 after un-jamming this. Almost every screw in a Teletype has a lockwasher. Notice that in the drawing, nut 3598 is partly hidden behind another part, and is shown in dashed lines. The lockwasher, if present, would be totally hidden in that drawing. That there is no lockwasher installed may be due to a drawing error. The fact that two different machines have had trouble in the same area suggests this.

Historically, not many people were really good at complex machine design. Maudsley (the first good lathe), Walschaert (locomotive valve gear), Edison (stock tickers), Burroughs (adding machines), and a few others go down in engineering history for this. Krum, who designed this Teletype, is one of the greats. If you work on machinery, you develop an appreciation for good machine design. There's a art behind design decisions, and often you can infer it from the machine itself.  It's an art steampunks should appreciate.

[oldskoolpunk]

Here's the stuck part, disassembled.


Those two parts were stuck together.


Cleaned, reassembled, and oiled.
This is the mechanism in the diagram above.

The tool shown is a spring hook. That's needed to get those little springs back in place without damaging them.

[oldskoolpunk]

OK, on to the next stuck part. Now it gets hard.


The selector unit. Most of this section is stuck.

The big dial is the "range finder", which sets the delay between the start of a cycle and the bit sampling times for each of the 5 data bits. The normal setting is 60. That part is OK; it was just cleaned in the previous step.


Here's the part that's stuck.

This is the serial to parallel decoder. For each of the five bits, there's a "sword" and a "T-bar". There's a stack of five of those assemblies, separated by thin steel plates. Each "sword", in sequence, is pulled backwards by cams so that, depending on whether the selector magnet is in the 1 or 0 position, either the left or right crossarm of the sword hits the crossarm attached to the selector magnet. This tilts the sword to the left or right position. Then the sword is pushed forward at its pivot, into the corresponding T-bar, hitting either the left or right side of the T-bar.  This drives the code rails and then the code bars of the typebar carriage. All this is stuck.


Rust and lubricant residue between those plates is the problem.

I think I can remove the entire selector mechanism and give the bottom part, not including the magnet coils, a good soak in a solvent. There are lots of adjustments in there I'd have to readjust if I disassembled the whole thing.

(All these pictures are mostly to help me reassemble the machine. This may be too much detail for most readers. Part of the reason I post this is to encourage people to build and repair more steampunk gear that works.)

[oldskoolpunk]

The selector unit removed and being cleaned.

It's not fully immersed because the electromagnets at the top shouldn't be soaked. I could take them off, but the I'd have to go through a difficult adjustment procedure to get them placed properly. I've done that before; it's not fun.


Cleaned and dry. Everything moves freely; no more stuck parts here.


The typing unit with the selector removed

Some other parts had to be removed to get the selector out. This isn't easy the first time, but once figured out, it's not hard. The U.S. Army and the Bell System once had schools for this.


Getting the five T-levers lined up with the yokes for the 5 code rails is tricky. This is what a 5-bit bus made out of levers looks like.

Getting it back in had me worried, but it was easier than getting it out.


T-levers back in place. With all the T-levers and code rails in the 1 position, they line up.


The entire selector back in place.

Everything which was stuck is now unstuck. This is about where I started with previous Teletype refurbishings.

Next, a full lubrication. 6 pages of lubrication instructions, 3 different lubricants, and over 600 oiling points.

Steampunk thought for today: a steampunk world would require massive amounts of maintenance like this. This is high-maintenance technology.

[rod-on]

Wow, there must have been legions of teletype repair & maintenance men with

6 pages of lubrication instructions, 3 different lubricants, and over 600 oiling points

[oldskoolpunk]

Wow, there must have been legions of teletype repair & maintenance men with

6 pages of lubrication instructions, 3 different lubricants, and over 600 oiling points

Right. Think of that when you're writing your steampunk novel. You need a lot of people to keep the machinery going. One genius inventor isn't enough. You need oilers, wipers, sweepers, mechanics, machinists...

[rod-on]

And one guy taking it all apart, cleaning it and restoring it!   

Don't forget him!

[oldskoolpunk]

Well, all three clutches on the main shaft are badly stuck. So it looks like I'm going to have to remove the main shaft, completely disassemble it, clean the metal surfaces, and reassemble it. This was a common enough operation that there's a U.S. Army manual which covers it, and an Associated Press manual as well.


Main shaft parts. From U.S. Army Technical Manual 12-2215.

I sent out a message on a mailing list for Teletype hobbyists, and five different people who'd done this task sent back comments, pictures, and references to manuals.


A main shaft, assembled. From Norman Marks


A main shaft, disassembled. From Norman Marks

So that's the next task for me.

(All this is because someone, decades ago, used the wrong lubricant.)

[Michael Farley]

Call me a philistine, but my first thought when I saw this was "ooh, that'd make a lovely sonic screwdriver".

[Kevin1632]

It makes me cringe to see that TTY called antique. The guy on the next bench fixed them, while I was fixing radios in the army.

Sigh,
Kevin