Film cameras
K-20 Aircraft Camera User manual
User manual for K-20 Aircraft Camera. 35 pages in English. Read the original PDF, download or print a copy without registration.
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- Brand
- Various brands
- Model / document
- K-20 Aircraft Camera
- Document type
- User manual
- Language
- English
- Pages
- 35
- File size
- 8.4 MB
- Category
- Film cameras
- Document date
- Not specified in catalog
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. THE SIGNAT SCHOOT FORT MON,IAOUTH, NEW JERSEY
ENIISTED DEPARTMENT
REPAIR OF AERIAL EQUIPMEIVT-SUBCOURSE ??3
: TRAINING MEMORANDUM NO. 1
K-20 AIRCRAFT CAfrIERA
NOTE: The material in the following paragraphs comprises essential supplementary instructional
material and is provided pending avait-abitity of offieial Department of the Army publication.
l. GENERAL. light loading. The shutter release and film
a. Aerial photography was used extensively transport mechanisms are interlocked to pre-
by military and civilian agencies prior to 1940. vent double exposures and skipped frames, and
operating But its value was reemphasized by World War have their controls located in the camera. The film is held flat dur- II, when it provided the photo-maps and photo- handle of the
graphs of enemy disposition, camouflage, etc. ing the exposure by a vacuum back and pres- sure plate' so invaluable to our photo-interpreters.
c. The lens used in the K-20 is prefocused b. The making of aerial photos can be ahaz' aperture ardous and expensive operation and the success and has a focal length of 63/s"'with
or failure of an entire campaign may hinge on openings from t/4.5 to f./.22. The between-the-
whether or not those photos are good. Sinee so lens shutter in which the lens is mounted has
mueh may be at stake, the Camera Repairman speeds of L/L25, L/250, and 1/500 seeond. The
must be sure that the equipment used is in tip- control knobs for both of these may be adjusted
eamera top condition and that all adjustments have through openings in the front of the
been made with preeision. eone.
c. This memorandum is designed to provide d. An oblique viewfinder, an exposure counter, a data-recording device, a film loading guide the neeessary instructions for Operating, Main-
taining, and Servicing the type K-20 Aircraft and a wall bracket for securing the camera to
Camera. It is intended, however, only for those the fuselage of the plane when not in use, are
already skilled in the field of Camera Repair. provided. ,*{r uS
e. The K-20 camera is made of metal (large-
2. GENERAT DESCRIPTION. ly aluminum alloys). When using an ordinary
ct. The K-20 is a manually operated aerial press camera for aerial work, the high velocity
eamera used to make oblique photographs for of the wind is apt to damage the bellows or
reeonnaissance purposes. Its light weight (Lts7u caLlse the bellows to shield a portion of the pic-
pounds when loaded) and cornpact dimensions ture area. This possibility is eliminated by the
(9Yz inches x 7r/2" x 11") make it ideal for metal lens eone of the K-20.
hand-held operation from standard military
aireraft. It is especially convenient for use from 3. DETAITED DESCRIPTION. the lighter planes where weight and spaee are o. The Type K-20 camera combines in one such important considera.tions. unit, all of its components; body, lens, shutter,
b. The camera makes 50-4x5 inch nega- magazine, film transport mechanism, vacuumI tives with a half-inch spaee between each on a back, operating controls exposure counter, re-
7 20, roll of 51/+,, film. This film has an opaque cording device, viewfinder, and means for at-
use. leader and trailer of 3r/z' each to permit day- taching it to the fuselage when not inView original page 2Page 3 · Read text
b. The references "right," "left," "top," etc., whose movements are synchronized with the in this Memorandum are based on the camera film transport and shutter release. Its function a
being held in the operating position. is to hold the film flat in the film plane while
(1) Camera Body the exposure is being made.
(a) The camera body is of cast alu- (5) Operating Handle
minum alloy. The front part, containing the (a) The operating handle on the
lens and shutter, in the cone, to which is at- right side of the camera is pivoted near its
tached the fixed handle, the wind and trip upper end. Rotating this handle fully fonvard
coupling shafts and the viewfinder. The rear of advanees the fiIm 4lb inehes and moves the ex-
the body contains the film transport, vaeuum posure counter one graduation. Returning the
system, and other mechanisms; the operating handle to its original position lowers the pres-
handle is attached to its right side in front of sure plate against the film, sets the vacuum
the exposure counter. This rear part of the piston, cocks the shutter, and loeks the film
camera is enclosed in the removable magazine transport mechanism.
eover. (b) Pressure on the trigger releases
(2) Lens and Shutter the vaeuum piston so that the film is drawn
(a) The shutter is mounted in the baek flat against the pressure plate; starts the
eone of the camera so that the lens will be pro- mechanism which releases the shutter; then re-
tected even when the eamera is plaeed nose leases the pressure plate so that it withdraws
down on a flat surface for loading. from the film, freeing it for the next cycle.
(b) The front cell of the lens has a (c) The shutter cannot be tripped
diameter of 44.5mm (L3/4 inehes) and also has until the film is advanced, and the film cannot
3 studs to aecommodate filters in special bayo- be advanced, until the shutter is tripped.
net mounts. (6) Exposure Counter
(c) The movements that cock and (a) The exposune counter is a dial,
release the shutter are transmitted from the on the right side of the camera, divided into
operating handle by coupling shafts, inside the 50 graduations. The return movements of the
cone, that eonnects with the shutter from the operating handle actuates the gears which
rear. move this counter forward one graduation be-
(d) The diaphragm and shutter fore each picture is made.
speed knobs may be rotated in either direetion (7) Recorder
to bring the desired setting under the referenee (a) The recorder provides a means
line which is seribed in the cone. No attempts for photographing data in an area approxi-
should be made to force these knobs past the mately r7n x 3 inehes on the long side of the
stops at either end of the seales. Also, it should negative, the data being written with a soft
be remembered that intermediate settings of pencil on the transparent card attaehed to the
the shutter will not give intermediate speeds. metal reeorder handle. A slot is provided in
(3) Film Transport Meehanism the magazine cover to receive the recording de-
(a) The film transport meehanism is viee. The cover eannot be attached or re-
a series of gears, cams and levers in the rear of moved with the reeording deviee inserted.
the eamera. ft is aetuated by a forward thrust (8) Viewfinder
of the operating handle. A speeial deviee disen- (a) The optical (Newtonian) oblique gages the film transport when 4Yz inehes of viewfinder is loeated on the upper rear seetion fiIm has traveled past the metering meehanism. of the lens cone. Depressing the small bloek (4) Vaeuum Baek Ieaf spring protmding from the right front of
(a) The vaeuum baek eonsists of a the base permits the lens to be raised or low-
retraetable pressure plate and a vacuum piston ered. The rear sight positions itself automati-
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I cally. When the photographer sights through by both handles with lens down and viewfinder
the viewfinder, with the ball of the rear sight towards bracket, slip the pins that form the
in line with the red lines scribed in the finder end of the viewfinder into the two hooks of the
lens, the area visible through the flnder cor- braeket, prcss the stud (camera support hook)
responds to the area covered by the negative. against the bracket-spring and lower the cam_
(9) Aecessories era until stud is engaged in the slot and spring
(a) has forced the stud into the countersunk re-
ililrrH",1Ti,,?11?u" is a sheet ceptacle of the bracket.
of hard rubber with a metal handle. It is in- 3. To rremove camera, press the
serted in the foeal plane slot during the thread- camera back against the spring, lifting it up
ing of the film to prevent the leader from eurl- and arvay from the wall
ing down into the body and preventing passage (f) Carrying Case of the film. The made 1. case is of flber and (b) K-20 Spools i aeeommodates camera the with acces- all its The film spools for the K-20 are sories, plus two spare rolls of film. all metal and will accommodat e 20 feet of film 2. The camera should be placed with the leader and trailer (81/z ft. each) at- in the ease with the recorder inserted, name tached . plate up, and its back to the partition i. e., with (c) Lens Cap operating handle next to the hinge. The filters The lens caps is a felt_Iined are kept in their compartment at the right rear
metal cap that is kept on the lens, at all times eorner of the case. (Make sure the eover is
that the camera is not in actual use, it proteets snapped shut.) The block inside the lid will ex-
the lens from dirt and damage. ert a slight pressure on the magazine eover to
(d) Filters hold the eamera securely when case is closed.
1. The filters for the K-20 are The eompartment at the left end of the case is
in bayonet mounts, with three spring clips en- for film and the fllm loading guide.
gaglng studs on the lens mount. T\vo filters, one 3. To remove camera from the
red and one yellow, ane provided with the unit. case, grasp it by both handles and Iift strar,ght 2. To attach a fllter, place it on up.
the lens mount so that the studs on the lens
mount engage the spring clips, then turn it 4. PREPARATION FOR USE.
cloelanrise until the projections on the springs a. Caution
pass over the studs and snap into place, secur- (1) Do not operate th,e camera wi,th, ing the filter. Reverse this proeedure to remove notlti,ng i,n tlte focal plane channel, because the filter. vaeuum baek is not designed to operate un- (a) CAUTION: Filters must damped. If it should be neeessary to operate be treated as earefully as lenses. When handl- unloaded, insert film-Ioading guide, the or a ing them, touch mount only the so that the pieee of paper pressure or old film under the glass be smudged will not scratched. or plate to cheek the free movement of the vacu- (e) Wall Bracket um piston DO NOT FORCE ANy PART OR 7. The wall bracket is attached MOVEMENT. Difflculty indicates that some-
to the fuselage of the plane with three No. 10- thing is wrong so eheek your previous adjust-
32 round-head screws. The camera should be ments before proeeeding. ALWAYS RELEASE attaehed to it when in the plane and not in SHIJTITER BEFORE PUTTTNG CAMERA
use, so that it cannot be accidentally dislodged. ASIDE. When the mechanism and shutter are
2. To attaeh the camera to the tripped and the cover is removed, DO NOT
wall braeket: elose the viewfinder, hold camera PRESS DOWN ON THE VACI"TUM PISTON.
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(4) Insert the film-loading guide in Ttris will upset the operating cycle and require
disassembly of both the camera and the shutter the focal plane slot, making sure that the pres-
mechanism for repairs to restore correct opera- sure plate is raised.
tion. (5) Pass the tongue down, around
b. Opening and elosing Camera dnd forward under the black guide roller and
(1) To oPen the camera, stand it on through the focal plane slot above ttre loading
its nose with the viewfinder away from you' re- guide. Next turn the camera around so that
move the recorder, unscrew the knurled cover the take-up spool faces you. Bring the leader up
screw knob on the left side of the cover. Now and baek between the metering roller (bottom)
slide the cover to the left and off the camera. and the two mbber pressure rollers, lifting the
There is a retaining clip inside the cover which pressure rollers to faeilitate passage.
prevents loss of the eover screw knob. (6) Remove the film-loading guide.
camera slide eover (7) fnsert the tongue in the lateral ,l Q) To close the
onto back of camera, making sure that grooves slot of the empty take-up spool and make sure
and ridges of light-trap are properly engarged that the leader is centered between the flanges
and recorder is not inserted DO NOT FORCE and feeds straight. Then wind two complete
A FIT. Difficulty indicates that correr is not turns of film on the spool with the take-up
properly plaeed on the body. Secure the cover knob. If this knob will not turn, wind and trip
by inserting the cover screw in its socket and the meehanism with the operating handle.
setting it up hand-tight. Insert the recorder as (8) Replace the magazine eover and
instructed in Paragraph 4 below. reeorder.
c. Loading the Camera (9) Wind and triP the meehanism
(1) With the camera on its nose and eight times to bring the sensitized film into the
the eover removed, see that the eamera is foeal plane. Be sure the trigger is tripped after
tripped, so that the pressure plate is raised to the last preliminary winding.
permit introduction of the fllm under it. If it (10) Set the exposure eounter at 50
is necessary to trip the mechanism, cheek the (zero), and the camera is ready for operation.
motion of the piston with a finger, to prevent CAUTION: CARE MUST BE TAKEN its hammering, making sure the finger is not TO PREVENT THE FILM FROM UNROLL. caught under a erosspiece as the piston rises. ING AND BEING FOGGED DURING LOAD. CALIIIION: DO NOT TURN THE ING.
TAKE.UP KNOB UNLESS THE MECHANISM d. Inserting the Reeorder IS TRIPPED! The recorder consists of a sheet (2) As the film is somewhat Pro- (1)
tected by its leader, it may be loaded in sub- of matte-surfaced cellulose-acetate secured to the dued light. Place an empty spool in the take-up a metal handle and is carried in slot in
end (the side toward the viewfinder), making magazine cover. Wind the meehanism and in-
sure that the crosspiece on the drive shaft sert the recorder in the slot on the bottom of
engages the slot in the spool flange and pin on the magazine cover in such a way that the
the far left hand spring is in the hole in the matte surface is toward the film. The words
other flange. "Top-REMOVE SLIDE BEFORE COVER"
(3) Plaee a full film spool in the should face the operator when the camera is
supply end in such a way that the tongue of in operating position.
the leader points up when it is toward Vou, (2) fnformation ean be written in
whieh will cause the film to unwind from the the thrnee reetangular clear areas on the matte
bottom of the roll. Break the seal and withdraw surface of the acetate with a soft lead pencil'
about 10" of leader. To facilitate writing, place the recorder on a
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flat surface so that the handle curves over the k. Making Pictures
edge' , (1) Holding the camera as directed
(a) CAtmON: When inserting in the above paragraph, sight ttrrough the
and removing the recorder, be sure to push it viewfinder at the area to be photographed.
straight in and out. TWisting is apt to tear the When the ball of the rear sight is in line with
acetate from the handle. the etehed cross-Iines on the finder lens, the
e. Opening and closing the Viewfinder area seen in the finder will appear on the nega-
(1) To open and close the viewfind- tive.
(2) Rotate the handle fully fonrard er, depress the blaek leaf spring on the right
advanees the film, cocksfront of the finder and raise the finder and return it. This
frame to the vertical. The rear sight is the shutter, sets the vacuum mechanism, and
automatically brought to the proper position advances the exposure eounter.
by a torsion spring on its shaft and the whole (3) To make the exposune, squeeze
finder is maintained in operating position by the trigger gently and steadily to avoid jarring
the leaf and torsion springs. the eamera.
(2) To elose the finder, depress the (4) Move operating handle fully for-
leaf spring and push back the top of the finder ward and return to prepare the camera for the
frame until it snaps into the folded position. next exposure
'''j ' L'" (5) Refer to the exposure counters.oPERATToN. ''r from time to time and when 50 exposures have
a. Remove earrlera from carrying case been made, unload as follows:
or wall bracket. l. Unloading b. Load the camera (1) When all film is exposed, operate c. Remove lens cap the camera 10 or t2 times, until its freer move-
d. Make sure lens is clean ment indieates that all the trailer has passed
e. Attaeh filter, if one is to be used onto the take-up spool.
desired data on reeorder and in- (2) Open the back and remove the t. Write
sert in slot. full spool, reseal it. This should be done in sub-
g. Raise the viewfinder dued light.
(3) Replaee magazine eover or re- lL. Setting the Lens and Shutter
(1) Determine the shutter speed and load.
diaphragm opening to be used and set the dia- rn. Storage ,
phragm and shutter accordingly. (1) When camera is not in use, keep
case. i. Checking the Exposure Counter it on the wall bracket or in the
(1) To keep traek of the amount
of film remaining in the camera, check the ex- 6. SERVICE INSPECTION, fiIAINTENANCE
posure counter. AND I.UBRICATION,
lnspection i. Holding the Camera a. (1) The eamera is held with the (1) Irr spite of its rugged construc-
fixed handle in the left hand and the operating tion, the K-20 and its accessories are precision
as such.handle in the right hand. The right index instruments and must be cared for
finger lies on the trigger, the back of the maga- (2) As with other equipment, when
zine rests against the ehest. Keep the elbows a unit is disassembled, make a rough sketch of
close to the body and do not allow any part of the relationship of parts or witness mark them
the camera to contact the plane lest the pic- if there is a possibility of replacing them incor-
tures be blurred by vibration. rectly.
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(3) Inspect all parts for wear, dirt, of at least 2 inehes, and three washers and nuts
scratches, deformities or any damage, whieh are needed'
might eause malfunction. (a) Remove the six screws on
b. Shutter the front of the shutter. The three larger ones
ones (1) The shutter of each K-20 is a hold the shutter and the three smaller hold on the shutter cover. standard unit, and is interchangeable with other (b) Screw the nuts all the way shutters. However the focusing posts on the up on the 3-inch long removal screws, add baek of the housing are machined for the par- washers, and insert the screws through the tieular lens and must neuer be i,nterch,anged.
c. Maintenance shutter removal plate and thread them careful- ly into the seating holes of the smaller shutter (1) Removing the lens cover screws. screw and rotate (c) T\rrn down the nuts on the Iens lock eam ,g.t"toosen
is neeessary to remove rli lr it three removal screws, taking eare to keep them equalized. the rear lens element from the shutter, the (d) While lifting out the shutter shellac sealing it must be softened.
1. Plaee one drop of grain the first part of the way in this manner, check
becomes free enough to alcohol at any point of the joint between the occasionally to see if it it out of the remainder of the way by lens and the shutter; it will spread all the way raise gently pulling on the removal plate. around. After two or three minutes, the ele-
ment may be unscrewed with the fingers. e. Replacing Shutter
2. After cleaning and re- (1) Before replaeing the shutter,
plaeing the element, reseal it by placing on the make certain that the position of the wind and
joint, one drop of a mixture of 7 parts grain trip couplings and the wind and trip coupling
alcohol and one drop orange shellac. shafts have not been disturbed. If they have,
it is neeessary to retime the shutter. (Refer to d. Removing Shutter
(1) Wind and trip the camera. par. 2. d., this sec.)
(2) To remove the shutter, take out (2) When ready to replace the shut-
the three large fillister-head serews and lift ter, guide same into position carefully using a
same out carefully. After this has been done, long pin inserted into one of the shutter serew
extreme care should be exercised not to disfurb holes as a locating deviee.
the trip eoupling and upper spring cup on the t. Timing Shutter
shutter, or the operating handle on the eamera, (1) Should the shutter be removed
in order to reassemble the shutter to the cam- for lubrication, the following procedure must
era body correctly. be observed in installing the shutter to time
(3) If the above are disturbed, it will same correctly. Set reta.rd knob at 1/500th of
be necessary to.retime the shutter. a second.
(4) fn some eases the shutter may (2) With the aid of a serew driver
shutter, fit so snugly that a speeial means of firmly inserted into the trip eoupling on the
grasping same is neeessary to extrieate it. A rotate same slowly in both cloekwise and coun-
shutter removal plate ean be quiekly made up ter-cloekrvise directions. If spring is tensioned,
by cutting a flat piece of 1/a. ineh thick wood or distinct elicks rvill be heard. Continue rotating
metal to a 7 inch square. Three t7o inch holes until elicks cease and then turn same to ex-
and allow same spaced 3yz inehes apart, in the form of an treme counterclockwise position
equal-sided triangle should be centered and to remain in that position.
drilled in the plate three 8-32 round-head (3) With the aid of a screw drivei
screws, 3 inehes long, having a thread length inserted into the upper spring cup, turn same
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Obtain three tO/32 fillis' slowly in a eounter-cloekwise direction while 1.T a observing the shutter opening and closing, until ter-head screws and turn down the heads to
clearance a distinct click is heard, and it is impossible to diameter of .247. This will provide
reverse the direction of the rotation. This eon- for the shutter cover holes.
stitutes one-eighth turn initial tension. (c) Remove the three shutter
(4) Wind and trip the camera and retaining screws (fie. 7) taking them out one
begin to wind the camera again, but stop ex- at a time, and, after removing each screw, re' one of the screws deseribed in the actly when operating handle is at the end of plaee it with
the forward stroke. (Do not complete the wind- preceding paragraPt, (a). The shutter retain-
ing cycle which normally would consist of a ing screws may be identified by the larger fil-
forward and backward twist of the operating Iister heads. (d) Set shutter sPeed knob mid- handle.)
way between tbe L/L25th and the 7/250th; re- (5) Set eamera down with eone fac- move the three cover retaining screws' and lift ing upwards.
(6) Insert trip coupling shaft (tong) off the shutter eover to expose the mechanism. (e) If the entire shutter assem- spring end toward magazine.
(7) fnsert wind couPling shaft bly is removed from the camera, the shutter
have to be retimed. (short) spring end towards magazine. If the will
droP of oil pin on the shutter end of the wind eoupling (f) A fraetion of a
shaft is not in correet alignment to receive the should be carefully applied to the teeth of the
grease slotted end of the upper spring eup on the shut- retard segment. Also, a thin film of
the maindrive bushing, r€- ter, hold operating handle to prevent it from should be applied to
moving and then turn the wind eoupling shaft lease-lever, trip lever, snubber, stop segment
cloekwise until it is in alignment. This ean be and retard segment. When applying lubrieantd,
easily determined by noting that the pins in use them sparingly, removing any excess.
both trip and wind shaft should approximately (g) The mechanism should be
parallel eaeh other. kept clean and free of all corrosion and rust.
Should any eorrcsion or grease be detected, it g. Lubrication
(1) Shutter should be rubbed off with a stightly oiled cloth; if the deposit is deep, it should be re- (a) The K-20 aircraft camera however,
contains a high-speed rapid-action shutter moved by using a piece of fine emery paper'
whieh is a standard unit that can be inter- making certain to elean the mechanism thor-
changed with other eameras, and whieh, for oughly after this oPeration. (h) All grit, sand, or any other effieient operation, depends largely upon proper
Iubrication and the absence of corrosion, rust, partiele of foreign matter should be carefully
and particles of sand or dust in the mechanism. removed from the meehanism partieular at-
The shutter requires more frequent lubrication tention being given the tripping parts.
than the slower speed type; therefore, the pro' (i) To replace the shutter cover'
L/]..2Sth eedure outlined in the following paragraphs set the speed knob midway between the
will be adhered to. The lens shutter should be md 7/250th marks; set the diaphragm knob at
Iubricated every 6 months, or after approxi- f4.5, and open the diaphragrn to its largest di-
mately every 5,000 operations. ameter aperture. The cover may then be put
(b) For lubrieation and inspee- in place and fastened with the three eover
serelvs' tion of the shutter meehanism, the following screws. Before tightening the cover
method is preseribed for removing the front make certain that the eover is fully seated by
eover from the shutter: without lifting the en- turning both the speed knob and the diaphragm
tire shutter assembly from the eamera. knob slightly back and forth to make proper
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reassembly instnretions are detailed engagement with the diaphragm and retard The mechanism. Remove the three special small enough to require no particular disassembly in- t
head shutter-retaining sefews' one at a time; structions.
and as each one is removed, replaee it with a (2) During disassembly of any or all
regular screw and lock washer. parts of the camera, a careful inspection of
NOTE: Do not usb the special small head each part should be made and any replacement
screws when operating the camera nor- or repair that is neeessary must be noted and
mally. They are designed only for holding reeorded.
the shutter securely in plaee while the b. Inspection cover is being removed, the purpose being (1) If upon disassembly, inspection to prevent possible disengagement of the reveals that a part is in need of replacement wind and trip rods from their couplings. which is a piece of an assembly or subassembly (j) To lubricate the leaf center, that is held together by a taper pin, the whole
remove the S pin and the three leaf center re- assembly should be replaced, even though only
taining screws. Lift out 'leaf center and put a a single detail part of same may be in need of
fraction of a drop of oil (oil, lubricating, gen- replacement. This procedure is necessary due
eral purpose, low temperature) on the five shut- to the fact that in taper pinned assemblies, onl5l
ter leaf pivots, and wipe.off all superfluous oil the dimensional relationships of individual parts
immediately. The leaf conter must not be dis' are held on shafts, etc., in exact correlation and
mantled. only complete assemblies are interchangeabie.
(2) Camera BodY Individual detail parts are not interchangeable
one assembly or subassembly to the other, (a) The lubrication given the from
iamera body mechanism at the time of manu- if they are a definite part of a taper pinned as- subassembly; because, of the fact faeturre should be sufficient to last indefinitely. sembly or
that in regulation manufacturing practice, fix- (b) Should unusual conditions re- hrres, and jigs control only the exact dimen- quire the mechanism to be relubrieated, the sional positions of parts of assemblies for taper teeth of gears and cams should receive a very pinning. The locations of the taper pins them- thin fllm of grease. Where they arle carried in selves are not held in close enough control to the castihg, o fraction of a drop of oil should be allow their being interchangeable on two as- apptied to the film roller bearing pins, the film semblies or subassemblies of the same kind. metering pinion, and to the two ends of the
pressure roller shaft. The vacuum back piston c. Repair
rod should receive one small drop of oil (oil' (1) All screw threads and taPs
lubricating, general purpose, low temperature) . should be rethreaded where necessary, and
if (c) No lubrieation should be aP- senews, bolts, nuts, and washers replaeed
burred or worn, with like parts in kind and size' plied to the vacuum back plston edge or to the Loose rivets should be replaced. All moving vacuum back cylinder wall. parts, gears, cams, shafts, bearings, ete., shor.v-
ing exeessive wear should be replaeed and prop- 7. DISASSEIABLY, INSPECTION, REPAIR, erly fltted. AII parts should be inspected and REASSEMBI.Y, AND FINAT TEST. tested for their assigned toleranees and if found
parLs d,. Disassembly to exceed the allowable figures, these
(1) For the proper order of disas- must be discarded and new parts installed. The
sembly of any particular unit, the reverse order rreplacements of all screws which originally had
of assembly should be followed as given in this shellac applied to them, should be dipped in
section under the heading of "Reassembly." shellae.
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d. Reassembly I ' all backlash in the entine system, while still
(1) General holding the operating handle firmly against its
(a) fn reassembly, the sequenee stop in the wound position.
of assembly of details, subassemblies, and as- 4. At this point the position
semblies is indicated by the order of their ap- of the lower pin should be 20 degrees clockwise
pearance in the text. Timing marks in the form from a vertical line intersecting the center of
of engraved lines and spot drilled marks are in- the winding bevel pinion which constitutes the
eorporated on all gears, where necessary, for proper setting.
referenee in reassembly. 5. The vertical line inter-
(b) In the system from the oper- secting the center of the winding bevel pinion
should be at a right angle to a line parallel withating handle to the shutter winding bevel
pinion, a differenee in aecumulated tolerances the straight edge of the mounting plate.
may occur, should it be necessary to make any (f) Should the angle as deter-
degree plus or minus of therepairs to the mechanism assembly r,vhieh mined be within 1
bevel pinionwould require the replaeement of worn or proper setting, the shutter winding
broken parts with new ones. can be reused after repairs have been made.
(g) Should the angle as deter- (c) This may necessitate replac-
ing the shutter winding bevel pinion with a new mined be in excess of 1 degree plus or minus of the proper setting, a new undrilled shutterone in which the angle of the location of the winding bevel pinion must be assembled intoIower pin must be determined, the hole drilled,
and the pin inserted. the mechanism assembly the backlash removed,
the correct angle determined, the lower pin (d) To determine whether or hole properly located and drilled, and the pinnot to replace the shutter rvinding bevel pinion, inserted.
it is necessary to check that the angle at which (h) Means have been provided
the lower pin positions itself, eonforms to a set- for making an adjustment on the trip linkting of exactly 20 degrees elockwise frorn the shaft whieh resets the shutter on the retumvertical with all baeklash removed, when the stroke of the operating handle. An adjustmentoperating handle is at its stop at the completion of 5 degrees is possible by turning the trip linkof a winding cycle. adjusting stud. The resetting of the shutter
(e) This can be eheeked in the must occur between 5 and 11 degrees of the end
following manner: of the return stroke and can be reeognized in
/. Trip mechanism assem- the form of an audible click.
bly by pressing trigger and pushing actuating (i) To determine whether the
link down and then moving the operating han- reset adjustment of the trip link shaft is eor-
dle forward and baekward through a complete rect, it is necessary to check in the follorving
winding cyele. manner
2. Hold operating handle /. Time shutter and assem-
firmly against its stop in the wound position. ble to camera body.
3. To set the shutter wind- 2. Begrn to wind eamera
ing bevel pinion, in order to determine whether very slowly moving the operating handle for-
the angle of the location of the lower pin is ward and then very slowly, baekward. -,.\bout L
eorrect, first ratchet the shutter winding bevel to 5 degrees before the end of the baekrvard
pinion in a eloekwise direction until it assumes stroke, the shutter should reset, whieh can be
a position approximately 20 degrees cloekwise obsenred by hearing a distinct click. If the dis-
from ttre vertical and then firrn same counter- tinct eliek is heard, no adjustment need be
clockwise as far as possible, which will take up made.
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3. If, however, ro click is d. The trip lever has a cam on its bottom Theard, (do not wr,nd cdrnera, again as this would side which disengages the stop segment when
cause sertous ilnmage) loosen the washer head the shutter is cocked. This allows the main
screw and turn the trip link adjusting stud drive bushing to rotate about L/16" in a clock-
until the click is heard rvise direction until its top cam engages the re-
noise 4. Tighten the washer head lease lever. This causes the clicking end of the winding cycle.serew, trip the camera, and wind the camera heard just before the e. When the trigger is depressed, theagain, listening for the reset click which should
release-be heard just before the completion of the re- main drive bushing is released by the
direction,turn stroke. Iever so that it rotates in a clockwise opening and closing the shutter blades. Its (j) Should it be impossible to speed of rotation is regulated by the retardmake the shutter reset by turning the trip link segment which impedes its movement by en-adjusting stud, the shutter should be r'ernoved gaging the lower cam. The retard segment isfrom the camera body and examined for a rea- positioned by the cam on the speed dial so thatson for the failure to reset. it is moved into or out of the path of the main
drive bushing to give the various speeds.
8. CYCLE OF OPERATION moved past (FAIRCHITD SHUTTERI. f. When the lower cam has a,. The Fairchild shutter is driven by a the retard segment, it engages the snubber
powerful coil spring loeated in the housing on which is positioned by a spring held by a shonl-
the rear of the shutter. The spring eneireles the der screw. The raised portion of the snubber
shaft assembly which rotates the main drive bears against the floating stud in the slot of
bushing. One end of the spring engages the the trip lever. This stud pushes the stop seg-
shaft assembly while the other engages the ment into the path of the main drive bushing
wind coupling which protrudes from the spring to stop its rotation. In addition the snubber
housing. Tension is held on the spring by means slows the main drive bushing, reducing the im-
of a ratchet pin that engages the wind eoupling pact with which the middle eam of the main
allowing the coupling to be turned in a eloek- drive bushing strikes the stop segment. Rebound
wise direction only. The tension is released only is prevented by the resenne tension on the
when the main drive bushing is allorved to ro- shutter drive spring.
tate. Both the wind coupling and the trip eoupl-
:ing are aetivated by conneeting shafts from the 9. DISASSEMBLE THE SHUTTER ASSEMBLY.
side plate assembly. a. Remove the shutter assembly.
Wind and trip the shutter. b. The main drive bushing is made up of (1)
three "layers" or cams on a single shaft. It (2) Set the camera on the bench
opens and closes the shutter blades by means rvith the cone up, remove the three large fll-
of a connecting link extending from an offset lister head serews and lift the shutter assembly
stud on the top cam to the blade control ring. from the camera cone
This connection link is held by means of a (3) Remove the wind coupling shaft
washer and "S" pin on each end. and the trip coupling shaft from inside the
c. The release lever engages the top cam cone. Remove the front and rear lens ele-of the main drive bushing. It is activated by the b.
rrounded eut-out on the trip lever whieh fits ments.
around the rounded portion of the release lever, (1) Remove the lens locking eccen-
pivoting release lever forward when the shutter tric and unscrew the lens elements.
is coeked and retracting it to free the main c. Remove all tension from the shutter
drive bushing when the trigger is depressed. spring.
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(1) Insert the blade of a serewdffiF and retard segment shaft, the retard segment
in the trip coupling and turn the coupling back spring, the spacer, and the retard segment as-
and forth until clicks are no longer heard and sembly. Remove the other snubber cam stop and
the shutter leaves remain open. retard segment shaft, the shims, the spacers,
d. Remove the shutter case cover. the trip lever, the shutter cam pawl, the spring
(1) Set the retard knob halfway be_ pivot screw, the snubber spring, and the snub-
tween L/L25 and L/250, set the diaphragm knob ber asseH"t*ou" ',
at f./4.5. Remove the remaining three fillister the shutter trip assembly.
head serews and lift out the shutter case cover (1) Drive out the taper pin and re-
assembly. move the trip coupling from trip shaft. lvith_
e. Remove the leaf center assembly . draw the trip shaft assembly from the shutter
case. Remove the shutter cam stop pin. ; (1) Remove the ,,S" pin to free the
Remove the shutter wind assembly. shutter operating link from the shutter operat- lx.
ing link pin. Remove the three serews and the (1) Remove the four screws from
Ieaf center assembly. the shutter spring housing. Remove the set-
(2) Disassemble the leaf center as- screw, the wind stop pin spring, and the wind
sembly' stop pin from the housing. Detach the spring !; (a) Remove the diaphragm as- clip. Remove the upper spring cup and wind
semblY' coupling, the shutter spring, and the cam shaft
1. unfasten the three dia- collar. Remove the taper pin, the lower spring assembly . ,n.t b&f, phragm seetor screws and rernove the dia- eup and the shutter trip cam frr ,
phragm sector. Remove the twelve diaphragm I O. REASSEMBTE THE SHUTTER ASSE'YIBLY. leaves. Unfasten the four screws and remove
the lower plate with the four between plate Replace the shutter wind assembly. spacers. a. Replace the .015,, spacer on the shut-
cam assembly. Insert the shaft through (b) Remove the shutter leaf as- ter trip
sembly. the cam shaft bushing. Secure the lower spring
L Remove the ,,S" pin and cup to the shaft with a taper pin. Add the cam shaft collar and the shutter spring. Replace the shutter operating link from the No. 5 link drive wind coupling in the spring housing andd se- Ieaf assembly. Remove the five eonnecting cure it with the spacer and spring elip. plaee links. Remove the pivot leaf assemblies in order the spring housing over the shaft assembly and beginning with No. 5 making sure that each fasten it with four screws. Replace the urind pivot shaft spacer is kept with the correct leaf stop pin, wind stop pin spring, and the setscrew. assembly. b. Replace the retard assembly and the (a'l The #S leaf as- shutter trip assembly.
sembly takes the .012 pivot shaft spacer. (1) In the following order, replaee
(b) The #4 leaf as- the .005" spacer, the snubber assembly, the
sembly takes the .016 pivot shaft spacer. snubber spring, the pivot serew, a .005', shim, (c) The #3 leaf the shutter cam stop pawl, and two .AOS,, shims.
sembly takes the .020 pivot shaft spaeer. Now insert the trip shaft into the bearing of (d) The #2 leaf the housing and replace the trip lever at the
sembly takes the .024 pivot shaft spac€r. same time sinee these two parts are interlock-
(e) The #1 leaf as- ing. Replaee one or more .005,, shims as needed
sembly takes the .028 pivot shaft spaeer. on top of the trip le'uer to take up the play. In_ the retard f . Remove assembly. snubber sert the cam stop and retard segment (1) Unfasten the ,,S,' pin and lift off shaft. Secure the trip coupling to the tripshaft
the retard pallet. Remove the snubber cam stop with a taper pin. Replace the shutter cam stop
??3.TR MEMO.I -11- LEAView original page 12Page 13 · Read text
pin in the trip actuating lever. Position the re- (1) If tltis initial tension is not nl
leaves willtard segment and .005" shim, the spacer, and wounal on this spring, the shutter
has beenthe retard segment spring. Then insert the not remain closed after the shutter
completeother snubber cam stop and retard segment tripped. This tension also insures a
clos-shaft. Replace the retard pallet and seanre it rotation of the shutter cam and complete
with the washer and "S" pin. ing of the shutter ]eaves.
(2) One full turn of operational ten' c. Replace the leaf center assembly. sion in addition is placed on this sprlng by t}te (1) Reassemble tt. rJ-"*io "r-sembly'turningoft}rewindactionoftheeatneraact. (3) If more than the initial tension (a) Starting with the .S1 leaf as- is plt on this spring and the camera is thensernbly and spacer, ptace flt";;"f ;r[;;li"; wound' a double wind will be placed on theolder in their corrcct p*itt;;;;-il;l;;;;
plate.spring,andthiswillresultineitherabmkenof
l. place the five connect- twisted shutter spring. (4) Turn the upper spring cup colm'ing links on the lower pliate in approximately " te" clockwise so that the shutter spring willthe right position.
P.Replacetheleafassem.slipintotheslotintheuppercup.Nowcon- tinue turning the coupling until the upperblies so that the two .t"a" on trr"- cup is latched by the shutter wind stop ""t"rnuliu" springengage the cormecting [nks.
8.Rep]acethepivotshaftpin.TheinitialtensionoflSSdegTeesisnowoni I spring'spac€r€ on the corr€ct l""f'"#'J.;i;:"dffi'; ihe shutter e' wind and trip the shutter'each slnc€r with a micrometer. (1) rnsert a screwdriver in the wind (b) Replace the between plate ,. and by turning the coupling one nevo- couplingslmcerc anal the upper p1"t" S;;;["-il;
plates with four screws.
(c) Replace the shutter operat- the.shutter sprins' Then plaoe the T:;Xtrl:: Irns link to the g5 r""f ----" i: 11"- t"ip coupling antl turn it fits then counter clocy.::.,^-with the washer and "s" pin"*;il; ""d-5;; f,ne cover assemory'^--^_r,r! (d) Replace the diaphragm as- J' lteplace
sembly.(1)Checktoseethattlreretard and that the R€prac€ the diaphrasm r Yl-ll}l5ldlaphragm Knoo !!\']rs sef, onyll/3'or/+'c'leaves on the lower plate and position on t"he (21 Fasten the cover assembly withdiaphragm sector on the leaves so that the stucl ,, ,, screws and lock washers' the threeon each of the diaphragm ;;;;il; i"";;
srot or the diaphragm *"toilfi;;;p'h*s; i"$"::#:tf#"1t"T".""1ff*,n*"*_must be at its fuIl opening when the trro index "
marks on the sector and the cliaphragm iiller "*tti.'t|h".= the shutter assembly in thegear line up.
(a) Sec.re t,,e dia_ il:"J;ffirrffn*jil$.THff*"H"Jilffiiffiphragm sector with ttrree screws. head screws. ;;1; with the three long filtister 9. Secure the leaf @nter Wind and trip the camera to ctreck the opera-
assembly with the three screq/s and lock wash- tion.
ers. Secure t}le free end of the shutter operat- THE TypE K-20 AIRCRArT CAMERA,
tng link to the shutter trip cam assembly with SIDE PLATE ASSEMBLY .the washer and "S" pin. ptATE ASSE1 Bty pROCEDURE. ll. S'DE
plate assembly. i Replace initial tension on the shutter o. Disassemble the side ' d.
:spring. (1) Remove the magazine cover.
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(a) Loosen the cover securing X, Detach the spring elip,
knob on the left side of the cover. remove the arm, and the counter arm return
(2') Remove the vacuum baek and spring.
bridge assembly (g) Remove the actuating disc
(a) Remove the nut, the actu- assembly from the.winding handle shaft.
atlng link stud, the cotter pin in the vaeuum (h) Remove the operating han-
back piston rod, and the four scnews (two on dle from the side pl?te.
each end of the bridge assembly). 1. Remove the trigger lock-
(b) Remove the four screws ing scrrew from th6 trip shaft.
holding the vacuum baek assembly. 9. Remove the taper pin
(c) Remove the two film spool from the winding handle shaft.
guide rods. 9. When the operating han-
(3) Remove and disassemble the side dle is removed, the operating handle spacer will
plate assembly fall free and the trigger assembly will be free.
(a) Remove the four screws Remove the trigger han- 4,
holding the side plate assembly to the cone. dle serew, the trigger screw roller, and the
1. Remove the two visible trigger from the operating handle.
scnews when the operating handle is in the nor- b. Reassemble the side plate assembly.
mal position. : (1) Replace the mechanism assem-
2. The other two screws bly'
may be removed by putting the operating han- (a) iteptace the trigger in the dle in the fonvard position . operating handle and secure it with the trigger
(b) Remove the clutch pawl serew roller and the trigger handle screw
spring and the metering cam follower arrn (b) Place the operating handle
spring. against the side plate with the operating han-
(c) Remove the taper ph, the dle in place and replace the winding handle
take-up spool shaft knob, the washer, and the shaft through the operating handle. Secure the
take-up spool ratchet assembly from the side operating handle with the taper pin. Replace
plate. the trigger loeking serew in the trigger after
f d) Remove the rear plate as- the trigger assembly is inserted through the
sembly. side plate into the operating handle.
Replace the aetuating dise l. Remo're the "S" pin from (c)
the stud on the shutter trip shaft assembly, assembly on the winding handle shaft. (d) Replace the counter aetuat- thus freeing the trip aehrating link.
ing arm with the counter arm return spring in 9. Remove the three screws place. Seeure it with the spring elip. near the bottom of the rear plate assembly.
(e) Replace the actuating disc 9. When the rear plate as- spa.cing collar. sembly is removed, the safety latch, shutter (f) Replaee the winding sector winding clutch spring, and the shutter winding on the winding handle shaft and secure it with elutch pinion will fall free. a taper pin. Replace the trigger spring. Check
(e) Remove the trigger spring to see that the counter aetuating arm is riding
and the taper pin and lift off the winding seetor on the trip lever rehrrn spring (loeated on the
assembly and the aetuating disc spacing collar. winding sector).
(f) Remove the counter actuat- (g) Replaee the rear plate as- .
: mg arm. sembly.
773-TR, MEMO-I ?Ic.,-to
_i:t->-t - **-r-S---= a ^ r - - - & - re"- liuView original page 14Page 15 · Read text
eamera, observe the l. Replace the shutter wind- winding and tripping the Ting clutch pinion, the shutter winding cluteh functions of the following parts:
disc.spring, and the safety latch in that order on (1) The actuating
Resets the shutter.the winding gear shaft. Hold these parts in (a) (b) Trips the shutter.place while fitting the rear plate assembly into
Depresses the vacuum backthe proper position. The 'operating handle (c)
should be in the extreme rear position when pitson.
the rear plate is fitted into place. The marked (2) The trip lever.
(a) Rotates the actuating disctooth space on the winding gear should engage
the marked tooth on the shutter winding clutch counter clockwise, on the baekward stroke of
pinion. Secure the rear plpte assembly with the wind handle, whieh resets the shutter and
three screws. Replace the trip aetuating link depresses the piston.
disc toon the stud of the shutter trip shaft assembly (b) Allows the actuating
engagementand seeure it with an "S" pin. fly cloekwise when released from
(h) Replaee the take up spool at the time that the trigger is pulled, tripping
ratehet assembly in the side plate. Replace the the shutter.
(c) Loeks the handle at the endtake up spool shaft knob on the take up spool
shaft with the washer in plaee and seeure it of the baekstroke by a latch. (d) Releases the lateh after thewith a taper pin.
: (2) Check the operation of the side trigger is pulled.
beplate assembly. (e) Permits the handle to
(a) Apply pressure to the aetu- moved in one direction only during the wind
ating link to simulate the tension normall.y sup- cycle by means of full stroke pawls.
plied by the vacuum back piston leaf spring. (3) The guard rail.
(b) Wind and trip the side Plate (a) Holds the trip lever away
mechanism. from the aetuating dise on the forward stroke.
(3) Replaee the side Plate mechan- (b) Prevents the camera from
ism on the cone and secure it rvith the four being tripped until the shutter is fully wound.
screws and lock washers. (4) The safetY lateh.
(a) With the operating handle (a) Locks the operating handle
in the extreme rear position, the two screws upon the eonnpletion of the wind cycle and pre-
just below the operating handle may be in- vents the fonvard stroke until the shutter is
serted. Then push the operating handle forrvard tripped.
and insert the remaining two serews. (5) The trip actuating link.
(4) With the two film sPool guide (a) The trip aetuating link re-
rods in plaee, replace the vaeuum baek assem' sets the shutter when the aetuating disc is
bly and secure it with the four screws. turned eounter cloekwise.
(5) Replaee the bridge assemblY (b) Trips the shutter when the
and seeure it with the four serews. aetuating dise is rotated cloekwise by piston
(6) Replace the cotter pin through aetion.
the piston actuating lever and vaeuum haek (6) The aetuating link.
piston rod. (a) Depresses the piston when
(7) Secure the achrating link to the the actuating dise is pulled counter eloekwise
piston actuating lever with the aetuating link on the baekward stroke of the handle.
stud and nut. , (b) Rotates the aetuating disc
c. fnsert the film threading plate, dummy eloekwise by piston tension when the piston is
film, or some paper in the focal plane and while released.
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(7) The counter actuating arrn. d. Wind and trip the side plate mechan-
(a) Moves the exposure dial ism. Load the magazine with dummy fllm and
ahead and reeords each exposure. replace the magazine pover. Set the camera up-
(b) Rides on and is actuated by side down with the cone pointing up. Replace
the winding sector. the trip coupling shaft and the wind coupling
(8) The cam follower arm. shaft. ,
(a) Engages the slot of the me- e;. Wind and trip the shutter assembly.
tering eam allowing the ratchet stop spring to Replace the shutter assembly in the cone so
engage the film metering ratchet, stopping the that the wind and trip couplings engage the
fllm wind when the metering roller has lolled wind and trip shafts. Secure the shutter assem-
off the eorrect amount of film. bly with the three long fillister head screws. (9) The winding sector. Wind and trip the camera to check operation. (a) Winds the fiIm on the for- d. Winterization.ward stroke of the operating handle by means (1) When. the K-20 should be win- of the upper part of the sector. terized. Winds the shutter spring on the (a) Most cameras designed forbackward stroke of the operating handle by use operation in normal temperatures will operateof the lower part of the sector. satisfactorily without winterization in tempera- (10) The metering ratchet assembly.
degrees (a) Acts as a clutch to stop fiIm funes down to approximately minus 20 Fahrenheit. Horvever, K-20 eameras which arewind action when sufficient film has passed to be regularly operated at temperatures belowaeross the focal plane.
(b) It is controlled by the eam plus 20 degrees Fahrenheit, should be winter- ized. Two K-20 cameras may operate quite dif-follower afm. ferently at low temperatures since the adjust- (11) The metering cam. ments and fits of parts are not exact. Conse- (a) Controls the action of the cam quently, the adjustment and fit of parts are offollower arm which rides on the cam. One revo- major importance. Well broken in (not wornlution is equivalent to the correct amount of out) K-20 cameras will not freeze up as quicklyfilm. It is geared to and rotated by the metering as new cameras.roller over which the film passes. (2\ How to winterize the K-20. (LZ} The shutter winding bevel pin- (a) The nesults of a recent lowion and shutter winding bevel gear . temperature study made of all standard aerial (a) Ttrrns the shutter wind shaft eameras lubricated with new low temperaturewhieh winds the shutter spring. lubricants indieate that sufficient elearances aI- (13) The wind eluteh pinion. ready exist on alrnost all camera parts and that (a) Acts as a clutch slipping past malfunctions at extremely low tempera-baekward four teeth over the pin on the shaft tures have been largely due to the use of im-on the forward stroke. proper lubricants. trt has been determined that
(b) Engages with lhe pin on the in nearly all cases complete, relubrieation alone
baekward stroke transmitting power to the is sufflcient to insure proper low temperature
shutter spring. operation. The following general instmctions
(74) The trip adjusting stud. apply for all standard aerial eameras.
(a) Adjusts the position of the 1. Each camera, ineluding
shutter reset aetion. all sub units and eaeh individual part thereof, (15) The non-reverse pawl. should be washed thoroughly by removing
(a) Prevents the take up spool every trace of the old lubricant. Dry cleaner's
from backing up. naptha (Federal Spec. No. *P-S-661), acid free
rl3-1R ME1,IO-1 -15- LEAView original page 16Page 17 · Read text
kerosene (Federal Spee. 'Nfo. W.K-211), or satisfactory. Continued use of TG-223 grease
lead free gasoline should be trsed. is recommended only when the new AN-G-3a
2. Relubricate sparinglY grease is not available
with the grease or oil speeified in the applieable (c) The reeommended oil is
Tbehnical Order. Spee. No. AN-O-6a. This oil has a low evapora-
(o) Grease is usuallY tion rate and is very satisfaetory for low tem-
perature operations.specified. All metal parts sueh as housings, cast'
ings, etc., which are subiect to mst and corro- (d) Fluid, hydraulic, petroleum
sion should be wiped with a'cloth impregnated base, Spec. No. AN-W-366b, h€IV be used as a
with the grease or oil. substitute. However, this oil has a high evapor-
(b) Exercise care to ation rate and should be reapplied frequently.
does not serve as a good corrosive pre-keep the lens and shutter leaves free from Also it
grease, oil, and grit. ventive.
(e) Gyro instrument oil, lubri- (c)' Oil should be used
usableon counters and similar intricate parts where eating, aircraft, Spec. No. AN-O-4 is
grease impedes proper operation at extremely when necessary and has good corrosion pre-
aslow temtrrcratures. Oil is also recommended for ventive characteristics, but is not as good
is rec-shutter leaf pivots to retain indieated shutter AN-O-6a at low temperatures, hence it
speeds. ommended only as an alternate lubrieant when
ANlO-6a is not available (d) ComPlete relubrica-
(4) Condensation on camera equip-tion is recommended twiie a year or as fre-
ment.quently as is found nec€ssary, depending upon j
the operating conditions and the amount of use (a) K-20 eameras to be used in
the equipment receives. . low temperatures should be kept in low tem-
3. .The. increasing of clear- perature storage, usually a protected outdoor
ances between shafts, bearings, and other wear- shelf or an unheated room.
ing surfaces is definitely discouraged as a (b) Do not bring equipment in-
means of freeing a camera. With very few ex- to warm air just prior to a cold weather mis-
ceptions, the normal clearances between run- sion.
ning parts will suffice for satisfactory opera- , L Cold equipment brought
tion at low temperatures. into warm air will eondense moisture from va-
(3) Low temperature lubricants. por in the warm air. This condensation or
(a) The recommended grease is "sweating" is harmful to eamera equipment
Spee. AN-G-3a, speeial for eamera use. and will freeze if the equipment is subiected to
7. The nomenclature on the freezing temperatures before eondensation has
containers of this grease will read as follows: completely disappeared.
, temperature, Spee. (5) Shutter sPeeds. "Grease, lubricating, low
use of camera win- AN-G-3a, special for camera use." - (a) With the (b) TG-223 grease has given ter lubricants, winterized between-the-lens
very satisfaetory results at low temperatures. shutters of the K-20 will operate in tempera-
However, due to the low viscosity and flash tures as low as minus 65 degrees Fahrenheit
point of the oil used in this grease, its service and at a speed approximately \O% less than
life at elevated temperatures is not entirely they operate at moderate temperatures.
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