facit_nea Clodoveu Davis

This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong.
===== Mechanical calculators: FACIT NEA =====

* [[etc|Back to Offline Hours]]

* [[calc|Back to Mechanical Calculators]]

This machine was manufactured by FACIT in Sweden, in 1946 (see [[http://www.xnumber.com/xnumber/facit_EA_NEA.htm|here]]). I bought it at an online auction site, in April 2019, and my first electrical FACIT. There was no way of knowing if the motor would run, since the seller only said it was completely jammed, and that he didn't have the power cable. In spite of two missing keys and a missing clear acetate window, I bought it anyway, since it was a bargain (less than $25) and due to the fact that photos showed the machine in its reset state, so I believed the seller didn't open it up or anything. Exterior was quite banged up, full of scratches and flaking paint, but nothing serious. 

This machine is similar to the TK, and was manufactured at about the same time. According to John Wolff, FACIT's first electrical machines from the 1930s only replaced the crank with a motor. The NEA is more sophisticated than that. Attached to the electrical motor, the machine has a set of mechanisms that replace the rotating crank to the right, and buttons for subtraction, multiplication and division. Clearing the input register is done using the motor ("zero" button to the right), but clearing the accumulator and the counter requires using the levers to the left. 

Multiplication is semi-automatic, meaning that the operator has to hold down the multiplication key and wait for the required multiplicand digit to show up in the counter, then moving the carriage left, and repeating the process. Division is fully automatic, though: after the dividend is input and added to the left of the accumulator, the input register is cleared automatically and the divisor can be keyed in and also shifted to the left. Then the division key starts up a mechanical algorithm by which subtractions and carriage moves to the right go on automatically until the remainder is zero or the precision limit is reached. 

My TK was my first restoration, in which I found nothing broken, so I expected the same from the NEA. Upon arrival, I cleaned it up a bit, and went through the usual spots where a FACIT locks up. I soon got the clearing levers and the keyboard to work. I also put together a first version of a power cable. Testing the motor, I was able to clear the input and perform adds with the first digits -- I dared not making anything more complicated and risk forcing the motor. With patience and observation, I eventually got it working correctly.

However, the NEA and the ESA-0 have a plastic gear early in the power train. None of my manual FACITs have anything like this. The plastic gear is probably meant as a "fuse", so that if something seriously locks the machine, this gear can break and the rest of the mechanism remains unharmed. In my NEA, one tooth was already missing from this gear, and my efforts soon caused another to break, and then two more, so it's now unusable. 

Now I'm trying to have this gear 3D printed, to check if the material used in these printers is as strong as the original one (I was told by gear makers that the plastic gear material is called "Celeron", as the Intel chips). 

**Have a mechanical calculator stored somewhere, and want to get rid of it? Send it to me!**

**1946 FACIT NEA s/n 271545**

{{ http://www.dcc.ufmg.br/~clodoveu/files/Images/FACIT-NEA/FACIT_NEA_as_purchased.jpg?500 | As purchased}}

**More about this machine**

[[http://www.johnwolff.id.au/calculators/Facit/Facit.htm | The evolution of FACIT calculators]]

[[https://www.youtube.com/watch?v=bf4zVBbo_Fs | Video: a FACIT NEA performing a division]]
Back to top
facit_nea.1556934978.txt.gz · Last modified: 2019/05/03 22:56 by clodoveu
Sitemap Recent changes
Show page
Old revisions