Facit NTK User manual

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Manual
for the
calculating machine
model
1{TK
A.KTIEBOLAGET ATVIDABERGS INOUSTRIER
STOCKHOLM . S\TEDEN

Contents
Preface
Tne ieatures of Facit NTK .
The x-orking parts of the machine . . .
The3registers...
Ciearing the registers
Onlr 13 setting keys .
Thecarriageshiftker.s. .,...;,,..
The tabulator ..,
Calculations are made bv turning the handle
Positive and negative turns .
The position indicator
Set up the figures with your left hand, turn handle with right . .
ivlarking the decimal point .
Care of the machine .....i
The machine is foolprooi . . .
Addition
Subraction
Multiplicat
Division 10n..
3
4
5
6
6
7
8
8
9
10
10
11
1,2
LJ
1,4
1,5
t5
1,6
t7
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Addition and subtraction of numbers consisting of more than 9,
but less than 13 digits . . . . 18
Subtracrion below zero , ... 19
Short-cutmultiplication... ..,.,..20
N4ultiplication involving addition of products , . , , 2l
Continuousrnultiplication.... ....21
Divisionbymultiplication, ...,.,.22
Rule of three . ..... 23
Reciprocalvalues ....24
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The
#&ffiEY ruYffi
masters
all the 4 rules
of arithmetic
by means of
10 setting keys only
The Facit 1O-keyed calculating machines have in a few
short years gained a ver\- strong position on all the markets
of the world by reason of their first class qr-rality and
reliability, in addition to the r-rseful calculations which they
are capable of handling.
As will be shown in this manual the Facit NTK is extremely
easy to operate once ]'ou have gained knowledge of the
correct way to go about it. For this reason it is really worth
while to study this little book thoroughly before commenc-
ing any work on the machine. l
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r&EIT ruTK
at your service. . .
-\nr-one n ith a prer-ior-rs knowledge of calculating machines
s il1 be interested to note ihat the Facit NTK, in addition to
the 1O-key sysrem. also shows the following features:
o'erall tens transmission in the product and multiplier registers,
n-hich facilitates shorr-ciits. gives immediate readings and ensures
complete reliabilrn-;
direct division setting *-hrch saves brain rvork and increases speec{;
rapicl zero clearing $-hich qrerrtiy speecls up operrltion.
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Learn to know the working parts
of the machine
. Clearing lever
for
product r.egister
Clearing lever
for
multiplier register
Handle
Clearing lerer
for
setting regisrer
Carriage shift keys
for step movements Setting keys Tabulator
In the above illustration, which shows the machine as seen
from above, the various operating levers and keys are easily
recogntzable. Try to memorize their names-that will help
you to get acquainted with the machine and its operation
in a short time.
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IiL:rririier
The Product register
-:: .',:::::rr:t. subtrlctic;t :::r ::--:-:t----i-
.-.: ::.- .:; .qJr si:- :. , r: - . - - -
::-:j-: reqi.ter. Th:. r:ii::;r al;o
..-t., a.. ;cilt.tinde: .::: ::..-: .: -:.-.--
::-:.
The Setting r€gisrer
I.:rr 1'-1nlg131 deprcsscd b, t:..:,-:lln:
., . . i.rrrr r-di,rrclr .:.t r:. i:_ r -
..::-: : :.:l,tcr.
The Multiplier register
I.n .rdrli.riorr ,h, rrrL.lr iplicr r-r,-i\r(r
srrowi llrc r:-:: b.,r oI ilcn,: a.{d.d
to3ctlrrr'. lrr rrru'riplication rhu irrulri-
plicl appcer'. iir rhi. r.egi'rer.
In,divi,jorr rhu a.t)wcr (rhc rlur;rirrrrl
ls shown i1ere.
f bt tr'n,t, tntl .'o) -d iur thc Ir,rtr rulct
ol artiL.bt,tcti. .tti to bc i<rt,nd o,t
the inside real coLar.
Ciearing the registers
Each of the three reqisrers has its owl1 clearing lever. Rc-
member to clear all the r egisrers after each complered com-
putation. This is done in the following manner:
\\ ith your lclt hand
prcss dorvn the lcft
h.rnd clearing lever,
.1ncl with your rigl-rr
press the trvo clearing
lclcrs togcthcr against
c;.ch other.
ti

are depressed according
to the numbers on thc
keys and in the order in
which they are read.
Exanrple: The numbcr 1365 is to be ser up. First press down
the figurc 1, then the 3, the 6, ancl tJre 5. For cach key
clepressed, the corresponding figure will appcar in the scming
register"
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Cnly 3{i s*tfi:i:g }eeys
fsvl t'!:t:l: r,,: e .ti;.ifrtit:*i _fr:: ,ii! ralcc;lafiarcs
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The numerals to be used
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Setting registcr

The c:iiiaQe shift ke1's
-.':,-.:. - t',.;r:.ritisnt. 'rnd with it the set-uP ttumerals itr
:,:e '-::i,ri resister. are mor-ed step b1- step to the right or
-e-:'r, means oi the red carriage shift ke1's' The arrow o11
rr; ^ei s indicates the dire crion in which the movement takes
-.''-:;e,
'.l ir c lcit l: -,.:
kcl n:tr:-.'r:l:
t1uil1!'1'i-S :rrr,
lei:.
ti :
J rai
f:f, i
,rI:
ff
::l a
fhc light liand sltift
Iev movcs thc nu-
,ncrals to thc light.
The tatrulator
Bi :r single depressio, of the red tabulator ker (to the r:ight
o11 rhe keyboard) the setrir-rg carrier is bror-rgl-rt to rhe left as
far as it vrill travel, and tl-iis is thc LisLIal p1'ocedure for
dir.ision.
At thc same timc t1-rc set-up llumbcr
;..urrtlctcd witlr rtot,ght' il ir corr-
i.rirr. li's th.rir 6 digits. Scc illtrrr.r-
tion,
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Calculations are made
by turning the handle
rVhen the required numerals have
been set up in the machin e, you can
add, subtract, multiply or divide by
a few turns of the handle.
$7hile the crank is being turned it is neces-
sary to pull out the handle (as shown by the
arrow) and keep it pulled out until the
required number of turns have been com-
pleted. All turning movemen* should be
carried out smoothly and evenly, not by
jerks.
The crank is
locked in nor-
mal position-
#
Pulling out the handle
in the direction shown
by the arrow unlocks
the crank,
Crank forwards (positive turn)
to add, and backwards (negative
turn) to subtract a number,
whichever the calculation re-
quires
A negative turn cancels a posi-
tive turn and vice versa-per-
rnitting instantaneous correction
oF cranking mistakes.
After cranking the necessary number of turns the crank must be ser
in its normal resting position before the mechanism can be cli:arecl
and a new calculating operation begun.
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Positive and negative turns
The number of mrns made is shown in the multiplier register. Tl-is
has a turn direction indicator which shows red for negative coupling.
Positive or negative coupling is determined as soon as the crank has
been turned about half an inch in the positive or negative direction,
irrespective of urhether the turn is completed in this initial direction
o, ,l.rr.d and complered in the opposite direction. A turn that has
bem initiated more rhrr, ,o inch must be completed. Negative coupling
is discontinued when the register is cleared with the clearing lever.
The multiplier mechanism counts the number of positive twrns when
the first and following rurns are positive. It counts the number of
negs.tioe turns when the first and following turns are negative.
If positizte tarnt dre rnad,e witb a negatirte coapled regitter, it counts
backw.rds, that is ro say, it akes off one for each turn. If a start
is made with noughts alone, or the zero line is passed during calcula-
tion, the complement of the last number registered in the multiplier
r.girt., is obtained automatically. (Complement of 1:999999999.)
The turn direction indicator on the
muitipli"r register -showing. that the
machine is ready lor negattve opera-
tion.
The position indicator
The red position indicators in the multiplier and product registers are
co.rtrollei by the red shift and tabulator keys and thus indicate in
which column position the machine operates at the moment'
Product register
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Multiplier register

D
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Set up the figures
with your left hand
- turn the handle
with the right
The illustration shows
which fingers are used to
press down the various set-
ting keys according to the
touch system for which the
machine has been designecl.
By practising this system right from the start you will very sool1
learn how to calculate speedily and correctly. You will find that after
a short period there is no need for you even to look at the keyboarel,
just like a trained typist who has no need to watch the keys.
By this left hani{ system the right hancl is always free for the recnrring
turning movements and elearing operations as well as for making
n0tes"
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Decimal point placement
The decimal pointers are position-
ed at the register windows. They
are displaceable and provided with
an "eve". Position the decimal
pointe'. so that the figure in the
"e1-e" marks the number of de-
cimals.
Example ol decimal point posi-
ticning in division:
33.769 _ | )
1s.14
How division is done with Facit
NTK is described on page 17. After
the dividend (33.768) has been set
up in rhe product reqister, set ont
the decimal point. - The "eye"
shows 1 1. After the divisor (28.14)
has been set up and moved over
to the left, the decimal point is
read off for this number. Note
that the number now has two
noughts after it, so that the sett-
ir,g up register shows 28.1400.
Tliese noushts are also counted as
decimals, i,hi.h *.un, that there
are 4 in all. The di{ference
between 11 and 4 is 7. The mul-
tiplier register decimal points
musc therefore be positioned so
that the "eye" shows 7. The result
ol the division is 1.2.
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Rwles t'or decirnal point
Addition and subtraction. ?osition the decimal point identically in the setting
and in the product register. Set.up all numbers with the same number of decimals
so that they come right relative to the decimal point in the setting register'
lvlultiplication" The number of decimals in the product register is to be the sar-ne
as the sum of the decimals in the serting up and riilltiplier registers. Mark the
position of the decin-ral point in the product register according to rule before
starting calculation.
Division. The number of decimals in the multiplier register is to be the same as
the difference between the number of decimals in the product and setting up
registers. You can avoid unnecessary calculating work if you determine the
position of the decimal point and how many decimals are needed in the answer
(quotient; before you start to divide. See also the example at the top of the page.
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Look upon your new Facit NTK as a
carefully manufactured instrument . . .
and treat it accordingly
The FACIT NTK is a precision machine throughout. It is designed
and built to give perfect service for many years. Regular attention
will guarantee good and reliable service.
Unlike the majority of calculating mdchines the FACIT NTK is
entirely enclosed and thus protected against dust.
Naturally the mechanism will be subject to
wear as the oil is gradually consumed. Like
needs cleaning, oiling and adjusting now
and then. This should be done once a year,
prelerably by e serviceman approved by
the makers.
Obviously the maker's guarantee will be
rendered inoperative if the machine has
been oilecl or repaired by unskilled iabour.
a certain amount of
all other machines it
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The machine
is foolproof
Tbis rneans that yow can never carry
out two simwltaneous operdtions by
mistake.
The machine is so designed that it automatically opposes every
manipulation which might jeopardize the reliability of the calculation
or possibly damage the mechanism.
Never ty to force the machine if it jams. Jamming indicates thet
some of the operating parts have locked-these must be restored to
normal position before you can resume calculating. Most of the time
you can unlock the parts by clearing all registers or setting the
handle in its original position. If these measures fail, you should get I
"t
in touch with an authorized FACIT mechanic. a
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'';ilri=,
&ddition
l.xanpLc: 3178 139,1 I [J5 I 8962 ?
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Set tip the first four numerals by clepressins the appropriate kevs'
Make one forward turn" Frc, the setting register thc nttmerals
will then be transferred to the product registcr, which n'i1l sholr'
Clear the setting register. Set up the next
numerals, 394, and make a forn'arcl turn. The total of thc two sets of
numerals will then appear in t1-re product register
i!:
1,1
l;:i::,:;
,.1
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Clear the setting register once more and continuc to
remaining items. If you have set uP the figures correctly,
trct register will show the total sum to be
The multiplier register, at the same t
add the
the procl-
time, records that ,voti havc
added 4 items in all [GEryFqL :-}
Clear all tbe registers when yotr. hate
c <trnple ted the c alculation.
Subtraeti*m
Example: 276543-80927 : ?
Set up the numerals 276543. Make a forward turn so as to transfer
the figures from the setting register to the product register.
Clear the setting register. Set up the lesser number, 80927' Make
,r backu,arcl turn and i:eacl off the resi"rlt in the
procluct register. This number is the clifference between 276513 a.ntl
80927.
Clear all. tbe rcgisters wben yorl hau compl.ete tl tbe calculati.ort.
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Muitiptricaticn
Example: 6943259'/.20'13 : ?
Set up the greater factor 6rq43259. Make 3 forward turns.
The multiplier register now shor.s
The product register shos,s (69,13259X3)
Press down, once only, the left hand carriage shift key ffi
This will cause the carriage to move one step to the left, which is also
recorded by the position indicator. Now make 4 forward turns.
You have now multiplied bv 43. Look at the multiplier register;
ir shows
The product register shows
Press the left hand shift key twice ffi (passing the figure 0 in
the n-rultiplier) and make 2 for*,ard turns. You have now completed
the multiplication and can read the answer (the product) in the
product register
The setting register shows the rnultiplicarrtl
The multiplier register records the multiplier
In this v/ay yolr are able to check that the correct manipulations
have treen carriecl out.
Clear all the regi,sters when you ha'oe completed the calculrttion.
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flivisicr:
[.xam pla: 9955 I 28 : 302 : ?
Sct up thc dividend 9955128 by the sctting heys. Press
lator ffi. Transfer the setting to the product register by
turn, thcn clear the setting and multiplier registers.
Set up the divisor 302 by the appropriate keys. Press
lator ffi. Make backward turns until you hear a bell
then one forward turn. The product register will now show
and the n-iultiplier register
Press the right hand shift kev ffi orr.. and continue with back-
ward turns until the bell rings, then one forward turn. The prod-
uct register now shows and the rnultiplier
reglster
Depress the right
handle backwards
Now the product
multiplier register
Once again depress the right hand shift
until the bell rings, then one forward turn.
the tabu-
a forwarc'l
the tilbu-
ring ancl
ffi or-t.. more and turn the
rings, then one turn forward.
an d thc
k.yffi , crank backwarcls
The product register shows
hand shilt key
until the bell
register shows
t@l a,d the multiplier register
Again press down the right hand shift k.y ffi and continue back-
x'arci turns until the bcll rings, then a forrvarcl turr-r. Thc product
register now shows nothing but noughts. Thc divisior-r coulcl be com-
pleted without leaving a remainder. The answer (quotient) is recordccl
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Fin the mr.rltiplier register
Clear all the registers when yott. have completed the calculation.
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Addition and subtraction
cf numbers consisting
of more than 9, but less
than 13 digits
[,i,i,it]tlt': 57 E3) L)65 7E2 155 E79 6n rc3-5 289 1i3 2n :::i ?
Stt r.ip as na11,v of the iirst figures of thc nurnber as thc sctting
rcgister can hold (9 irgures). The two last figures, thercfore, havc
to be left or.it. Depress the left hand shift key Q twice (or as lnany
times as there are remaining figures in the number).
\Iake a fors.ard turn.
The product register shc*'s
Clear the settir-rg register. Norr- set
ancl rrake a forward turn. The
up the two remaining figurcs, [i2,
product register now shows thc
complete number
C1e:rr the setting register. Set up thc first 9 figr.rrcs in ti-rc ne xt
irurnbcr. Press the left hand shift kcy tl thrcc tirnes ancl mal'c r.r
torr ;rrcl turn. Tlle proclnct register nclrv sht-,rvs
Clcar the setting registcr. Sct up the threc rcrnaining figr"rres, 1.63, and
rutrkc a forward turn.
Thc procluct register now sl-iows thc tetal sunr of tl.rc trvo ;rclclcel
riiimbcrs
Cle,rr thc
ta
sctting register again. Scr Lrp rhc first 9 ligurcs uI thc