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Addo-X 20 adding machine

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M.S. View Drop Down

Joined: 26 February 2012
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Posts: 1
  Quote M.S. Quote  Post ReplyReply Direct Link To This Post Topic: Addo-X 20 adding machine
    Posted: 26 February 2012 at 9:03am
Hello all,

I recently acquired an old adding machine, of the Swedisch brand Addo (Addo-X, model 20). It's still in working condition, but I was wondering if anyone knows anything about them. My main questions are:

- How does it work, exactly? It's a 10 digits system, but there are other . whose function isn't very clear to me. See the picture below.

- How should I clean of the rust and dirt? What material is the machine made of? I suppose most components are made of metal, so what is an efficient way of cleaning them?

- Would it be risky to open them up to have a quick look inside? I don't have any experience with these things.

- Any useful links, books, ...?

Image: http://www.rechnerlexikon.de/upload/1/1c/AddoX20-Prosp.jpg

Edited by M.S. - 26 February 2012 at 9:04am
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KenA View Drop Down

Joined: 23 May 2012
Location: Ascot, UK
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  Quote KenA Quote  Post ReplyReply Direct Link To This Post Posted: 23 May 2012 at 3:53pm
Hello M.S.,

I was a service engineer with Addo UK for quite a few years.
I never actually worked on this particular model, although I did pay a visit to one of a similar vintage on a USAF base.
In the UK we went straight from the full-keyboard Addo, i.e. keys 1 to 9 in every column to a much more streamlined Addo-X Model 40.
I am sure that the working principles are the same.

The keys along the top of the keyboard, from left to right are: -

Multiply - an 'X'
Minus    - a '-'
A latch for the Minus Key to subtract on successive cycles.
Subtotal - a square.
Total - a star.

In front of the last two your picture has a key with what looks like a 'c' on it, but I don't remember this key. The only thought I have is that, seeing this is a hand-cranked machine, the Total and Sub-total keys may have latched down and if you changed your mind before pulling the handle you could cancel that operation.

The small knob next to the zero key is both an indicator for the digits keyed in (it steps to the left for each digit entered) and a cancelling device (you slide it back to the right to cancel the digits entered).

In operation you key in each number just as you would on an electronic calculator and then pull the handle to execute a plus operation.
(Electric machines had a plus bar that you pressed with the heel of your hand).

The number entered will print on the paper.

The same operation with the Minus key latched down subtracts the number.

The multiply key 'X' simply stops the digits entered from being cancelled at the end of a cycle and enables multiple additons.
To use this feature you enter the multiplicand and then pull the handle the number of times represented by the least significant digit of the multiplier, then press the zero key once and do it again for the next digit of the multiplier. Continue this process for all the digits of the multiplier.

To get the answer you press the Total key and pull the handle.
This prints the total amount whether of a listing of different amounts or a multiplication.

The sub-total does the same thing without clearing the register so giving, effectively a running total.

We used only methylated spirits, i.e. de-natured alcohol, for cleaning although on plastic or painted parts it is better to go gently.

Wire wool could be used on any rust.

Sewing machine oil on all bearings and pivots after cleaning.

There is no real danger in taking the case off (it will be necessary to remove the carriage that holds the paper roll first), but how much cleaning you will be able to do without dismantling the machine is debatable. It depends to some extent on what state the previous oil is in. If it is very old it may have oxidised to a resinous condition.
I once had to look at three machines which had been in a cupboard at Oxford University for some years and were stiff with coagulated oil.
I got one working and started on a second. The next day I found that they had dunked the third in an ultrasonic cleaning bath, but it still did not work. I found on dismantling it that the solvent had reached the oil, but not flushed it out and when it had dried out it was worse than before. I don't think you would get that effect with alcohol, but squirting some into the bearings and cycling the machine is probably the best way. If it is working it probably only needs oiling after removing superficial dirt.

I don't know of any publications, but you can email me with any specific problems.

All the best, Ken.
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LazarusOwenhart View Drop Down

Joined: 31 August 2012
Location: Norfolk UK
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Posts: 12
  Quote LazarusOwenhart Quote  Post ReplyReply Direct Link To This Post Posted: 05 September 2012 at 5:32pm
If you decide to dismantle it have a camera on standby and make sure you photograph EVERY part you remove. Even better video the process and talk yourself through what you're doing. As long as you have a concise visual record of what you're doing even the most complex machine is a diddle to re-assemble. The key is patience. As for the rust I suggest, like the previous poster, wire wool. If the paint is bad consider respraying it but make sure you take detailed pictures of any painted on graphics or stickers before you do so they can be re-produced. As for removing dirt, the ultrasonic bath seems like an excellent idea but disassembling the machine first would probably yield a better result. Then you can lubricate it with good quality sewing machine oil as you put it back together. If you do decide to take it apart and put it back together, videos like that belong on YouTube dude :) Good luck.
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