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Hagelin C-446
The C-446 was a mechanical cipher machine developed in 1944/1945 by Boris Hagelin of A.B. Cryptoteknik in Stockholm (Sweden). The design is clearly based on the earlier M-209. It comes in a similar sturdy case and is very robust and reliable. The tools are stored in the top lid.
 
Unlike the M-209 however, the C-446 is locked with two different keys (see below). Furthermore, it has two different printers, one for the plain text and one for the cipher text. Two separate paper reels have to be mounted inside the top lid.

Three versions of the C-446 are known:
  • C-446
  • C-446-A
  • C-446-RT
  
Hagelin C-446A

Although we know that the RT version uses a one-time pad (OTP) cipher tape, rather than cipher wheels, the differences between the C-446 and the C-446-A are currently unknown. It is quite likely though that the A-extension only refers to small manufacturing changes, just like with the M-209 A and B models.
 
The C-446 came in commercial (grey) and military (green) variants. Apart from the outer colour, they were functionally identical. The machines shown on this page are all of the military type and were used by the Dutch Navy and the Norwegian Army.

The image on the right shows both versions side by side. The one on the right is the standard C-446-A that has 6 cipher wheels. The leftmost one has a 5-bit tape reader instead of the wheels. It uses a so-called One Time Tape (OTT) and is theoretically unbreakable.
  
The standard C-446A (left) and the special C-446/RT (right) side-by-side

Many C-446 machines that have been found in recent years, appear to be incomplete due to de-militarisation procedures when they were finally scrapped. As a result, some of the bars and lugs are missing from the cage inside the machine. In many cases, even the serial number plates have been removed.
 
C-446-A
The machine shown below is a standard C-446-A. At first sight it is very similar to the war-time M-209, which in turn was based on the civil C-38. The machine has 6 non-removable cipher wheels that protrude the top lid at the bottom right. To the left of the wheels is a small letter-counter. At the far left are the two printers.
 
Unlike the M-209, the C-446 can be locked properly. It has a lock on the top cover and one on the machine itself. Both locks are different, so different keys were supplied with each machine. One key could only open the cover, whilst the other key (the so-called officer's key) could open both locks (see below).

The machine is operated by a crank at the right. In the image, the crank is shown upright, in the operational position. The mechanism is operated by pressing the handle down to the front of the machine (carefully).
  
The C-446 opened and ready for use

Different versions of the C-446-A are known. The two rightmost images below show two variants. The one on the right has some additional mechanics just behind the printer. This was used to allow it to be driven by an external keyboard attachment. Strangely, there is no way to tell these differences from the model number of the machine.
 
The The Hagelin The The Close-up The The

 
C-446-RT
This variant of the C-446 uses a paper tape reader instead of the 6 cipher wheels. Using a tape reader with a random cipher tape (RT) produces a much stronger cipher. In fact, when the tape is truely random, the cipher is unbreakable.

Unfortunately, most of the bars and lugs are missing from this machine. They were removed as part of the de-militarisation procedure, as can be seen in image #4 and #5 below.
  
C-446-RT ready for use

 
The C-446-RT Left Left A Opening Loading The

 
Tools
The C-446 comes with a set of tools that are usually stored inside the top cover. At the right are the screwdriver and the tweezers. At the left are two metal containers. All tools are clearly visible in the first image below. One or more tools are often missing from machines found today.
 
The tweezers are needed to feed the paper through the printer and to remove any clotted paper from the mechanism. The screwdriver is needed to disassemble certain parts and to make adjustments to the mechanism. Please note the special gap in the blade of the screwdriver.

Also stored in the top cover are two small metal containers. One contains oil that can be applied with a needle that is attached to the cap. The other one contains a set of replacement ink rolls. Please check the images below.
  
The tools of the C-446

 
The The The Tweezers Bottom Taking Taking Closing

 
Keys
The C-446 was usually supplied with a set of 4 keys: two operator's keys and two officer's keys. They can be identified by the number of gaps in the grip. The operator's key has one gap, whilst the officer's key has two of them. The gaps are clearly visible in the images below.
 
The operator's key can only be used to open the top cover, but the officer's key can be used to open both the top cover and the machine itself. The latter is needed in order to set the position of the pins and lugs as part of the daily key. The operator could only change the settings of the wheels (message key).

The keys of all C-446 machines are different and the chance that a key fits another machine is very small. Furthermore, different versions of the cross-lock have been used: long, small, simple, complex and safety versions.
  
The four keys that were usually supplied with each machine: two operator's keys and two officer's keys.

 
About missing keys
Most ex-Navy versions of the C-446 that ended up on the Dutch surplus market, have their keys missing. And even worse: in most cases the machines are locked. Over the years, we've seen many machines that were severely damaged by a new owner, in an attempt to open the locks.

Our C-446-RT, for example, was locked and came without the keys. In this case, we were lucky. We tried the keys of another C-446 unit and, with a little wiggeling, we managed to open both locks. Apparently, the locks of both machines were nearly identical. Since then, we've tried the keys on many other machines, but to no avail.
 
If you ever find a C-446 with the locks closed and without any keys present, please don't attempt to open it yourself as you are likely to cause permanent damage to the machine.

Instead try to find a good lock-picker. Although cross-locks are rather complex, they can be opened without damage.

The image on the right shows lock-picker Walter Belgers (Netherlands) opening the C-446 of a friend at the Dutch Radio Ham Museum in December 2008. It took him about two minutes to open two machines.
  

 
The The The The Another

 
ID Plates
The C-446 normally has an ID plate that is mounted over the lock in the top cover, at the front of the machine. This ID plate is shown in the leftmost image below. Quite often it is missing, as it was sometimes removed as part of the de-militarisation process before the machines ended on the surplus market. The serial number can also be found at the front of the machine, where it is engraved in the bottom plate.
 
Many, if not all, of the C-446 machines that were used by the Dutch Navy, were delivered by a company called Koopman & Co. These machines have an additional manufacturer's plate attached to their side. The Koopman & Co plate is shown in images #4 and #5 below.

Koopman & Co was a trading company with offices in Amsterdam, Bandoeng and Djakarta (in the former Dutch East-Indies). It is unclear whether, apart from the name tag, they made any modifications to the machine, prior to delivery to the Navy. It is unlikely however.
  
Serial number engraved in the bottom plate at the front of the machine.

The C-446 machines used by the Norwegian Armed Forces had a manufacturer tag that was painted to the back of the machine. It is shown in image #3 below. It shows that the machine was manufactured in Sweden by A.-B Cryptoteknik.
 
Serial ID Manufacturer's Name Position The

 
Opening the case
The machine is usually opened with one of the keys (the operator's key or the officier's key). The top cover is hinged at the rear and can not be removed. After opening, the top cover should be locked into position with a special spring-loaded bracket at the left (see picture #1 below).
 
In the images below it is shown how the top cover should be locked into position. At the left of the machine - to the rear of the printer - is a shiny spring-loaded metal bracket. Rotate this bracket clockwise (i.e. towards the rear).

A gap in the bracket should mate with a pin inside the top cover (at the left side). You may have to open the cover a bit further to allow the bracket to pass the pin first. Release the bracket and ensure that the pin has engaged the gap. Do not forget to release the bracket before closing the case again.
  
The spring-loaded bracket should mate with a pin in the top cover.

 
The The The The The

 
Closing the case
Before the case of a Hagelin machine can be closed, the handle at the right first has to be pushed down completely. If you are not familiar with Hagelin machines, you may have trouble pushing down the lever to its home position, sometimes leading to broken handles.
 
Whatever you do, never use excessive force! Although Hagelin machines are very robust and tough, axles can be broken easily when enough force is applied. Once broken, these machines are very difficult to repair.

If the lever won't come down, it's probably because the mechanism is blocked. The most common reason for this is the fact that it always blocks after (de)coding a letter. All you should do at this stage is selected another input letter by rotating the letter knob at the left (#2). Now you should be able to bring the handle down.
  
The handle in the upright position

Once pushed down, lock the handle in place with the small lock (#3). Next, pull-out the grip (#4) and fold it upright (#5). Please check that the grip is full aligned (#6). Ensure that the top cover is no longer locked in position, by releasing the bracket at the left. You may now close the case (#7).
 
C-446-A The Rotate The Pull-out Pull-out The The

 
Loading paper
Depending on the model, a Hagelin machine takes one or two paper reels. In the example below, we are showing how to load paper into a Hagelin C-446 machine. Please note that there are two different types of paper: standard paper tape, and pre-gummed paper tape. The paper is 9.65 mm wide and the hole at the centre of a reel is ±11 mm. A full roll is about 10 cm wide.
 
Please be careful with pre-gummed paper. Over the years, this paper is likely to have become brittle and will break easily. Furthermore, gummed paper has the tendency to attract moist, making it sticky and potentially block the machine.

Place the rolls in the lid of the machine and load them one at a time. Lock the roll with the metal bracket that 'snaps' into position. Then feed the machine over the first guide, through the second guide, into the printer. Feeding it into the printer may be a bit tricky.
  
Three paper rolls for the Hagelin C-446. The frontmost one is pre-gummed (read the warning).

Make sure the paper tape curls up a little before it is entered through one of two slots at the rear of the printer mechanism, so that it can be fed through the printer easily. This is best done with the pincer that is usually stored in the top lid.
 
Feed Close-up Close-up Make Two The Use Once
Three Pre-gummed This

The paper used in the C-446 is the same as used in the M-209. It is very difficult to find these days and in many cases, the pre-gummed tape has either become 'pudding' or brittle. If you have any surplus rolls left, please contact us.

 
Further information


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