[Depression Position Finder M1907]
[From the U.S. Government Publishing Office, www.gpo.gov]

wTAI 9-1685
Document Reserve «—■—।
WAR DEPARTMENT
TECHNICAL MANUAL
•M
ORDNANCE MAINTENANCE
DEPRESSION POSITION FINDER
M1907
October 14, 1941
NON-CIRCULATING
NTSU LIBRARY
TM 9-1685
1-2
TECHNICAL MANUAL No. 9-1685
WAR DEPARTMENT, Washington, October 14, 1941.
ORDNANCE MAINTENANCE
DEPRESSION POSITION FINDER M1907
Prepared under direction of the Chief of Ordnance
Paragraph
General_______________________________________________:-------------------- 1
Description----------------------------------------------------------------- 2
Operation___________________________________________________________________ 3
Inspection------------------------------------------------------------------ 4
Maintenance and repair------------------------------------------------------ 5
Care and preservation_______________________________________________________ 6
Spare parts and accessories------------------------------------------------- 7
Page
Appendix. List of references_______________________________________________ 27
1. General.—a. Purpose.—This manual is published primarily for the information and guidance of ordnance maintenance personnel.
6. Scope.—This manual supplements the Technical Manuals which are prepared for the using arm. It contains general descriptive matter and detailed instructions for the maintenance and repair of the instrument by ordnance personnel. Figures which accompany the manual show the placement and method of fastening of each of the component parts of the instrument.
c. References.—The appendix lists Standard Nomenclature Lists and other publications pertaining to this instrument.
2. Description.—a. General.— (1) The depression position finder M1907 is an instrument used for measuring from heights above sea level, the true horizontal range of an object on the surface of the sea and also the azimuth of the object from the azimuth reference line.
(2)	The instrument consists essentially of a telescope, mount, and pedestal. The mount carries the telescope and contains suitable mechanisms for directing it. The mount is accurately leveled on the pedestal by three leveling screws. When the telescope is directed on the water line of a target the depression angle is measured mechanically, and the corresponding horizontal range, corrected for curvature of the earth and normal atmospheric refraction, is read directly on a range scale graduated in yards. A compensating mechanism corrects for tidal variations, abnormal atmospheric refraction, and for heights of instrument other than those for which the range scale is
415045°—41---1
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TM 9-1685
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ORDNANCE DEPARTMENT
calibrated. Azimuths are read directly from an azimuth scale and subscale.
(3)	The depression position finder M1907 is superseded by the depression position finder Ml.
(4)	The instrument is built in several classes, designated alphabetically as listed below, to cover the varying needs of the service. The depression mechanism components and the range scale supplied determine the class of the instrument.
Height of emplacement
Class	above sea level (feet)
A________________________ 35	to	80_________________
B________________________ 60	to	145_________________
C_______________________ 125	to	300________________
D_______________________ 280	to	690_________________
E________________________ 90	to	210________________
F_______________________ 165	to	400________________
AA_______________________ 25	to	60_________________
BM_______________________ 60	to	145_________________
CM______________________ 125	to	300________________
DD______________________ 160	to	400_________________
DM______________________ 280	to	800_________________
DM1_____________________ 380	to	1,140_______________
DMM_____________________ 280	to	800_________________
DMM1____________________ 380	to	1,025_______________
EE______________________ 300	to	750________________
G_____________________ 1,200	to	3,500_______________
H_______________________ 280	to	760________________
K_______________________ 310	to	900________________
Range (yards)
1,500 to
1,500 to
1,500 to
1,500 to
600 to
600 to
1,000 to
1,500 to
1,500 to
1,000 to
1,500 to
2,000 to
1,500 to
2,000 to
1,000 to
2,500 to
5,000 to
3,000 to
12,000.
12,000.
12,000.
12,000.
9,000.
9,000.
6,000.
15,000.
20,000.
6,000.
20,000.
20,000.
20,000.
20,000.
6,000.
25,000.
30,000.
25,000.
Z>. Telescope.— (1) The telescope for depression position finder M1907 is shown in figures 1 to 4, inclusive.
(2)	The telescope is furnished with two interchangeable eyepiece assemblies. The optical characteristics with the eyepieces furnished are as follows:
Magnification_________________________
Field of view_________________________
Diameter of exit pupil________________
Effective focal length of objective___
Effective focal length of eyepiece____
Apparent field of view________________
15X_______________
3°_________________
0.20 inch__________
25 inches__________
1.667 inches______
45°________________
25X.
1°.
0.12 inch.
25 inches.
1 inch.
45°.
(3)	The optical system includes an objective (A36637), two porro prisms (A36636), a reticle assembly, and eyepiece assembly (C44216 or C44217). The image produced is erect.
(4)	The eyepiece is threaded into the eyepiece adapter (20A). Each eyepiece assembly contains an amber filter (A36635) assembled in a filter holder (20N). The knurled arm of the filter holder, used for adjustment, projects through the edge of the eyepiece cap.
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DEPRESSION POSITION FINDER M1917
(5)	The reticle frame (20G, fig. 3) contains two fine platinum cross wires which locate the vertical and horizontal axes of the field of view. Electrical illumination is provided and a shutter sleeve (20B) controls the degree of illumination.
(6)	The adjusting pinion knob (17K) controls the movement of the cross wires into the focal plane of the objective.
(7)	The mask assembly (C44262, fig. 2) enables the observer to relax the eye that is not focused on the telescope. It is adjustable and can be set to suit the observer. The head should not be rested on the mask or any part of the telescope.
(8)	The telescope is positioned on the mount by two telescope trunnions (5C, fig. 1) which are retained in the yoke by an accurately machined bar (18D, fig. 3). The bar is secured to the under side of the tube (9C) and rests on the pin (3B, fig. 9) in the head of the compensating screw. The optical axis of the telescope is parallel to the lower surface of the bar.
(9)	The counterweight assembly (B129215, figs. 2 and 4) is adjustable for proper balance of the telescope. The sunshade (9F), although removable, should be kept in place when the telescope is in use, as its weight is necessary to secure the correct balance.
(10)	The safety clip (18F, fig. 8) which is attached to the body tube bar (18D) hooks under the head of the compensating screw and prevents accidental lifting of the telescope.
c. Mount.— (1) The mount for depression position finder M1907 (figs. 1 and 5 to 10) supports the telescope and contains leveling, azimuth, and ranging mechanisms. Figure 10 refers only to the class G instrument which varies slightly from the general type in construction of the tangent screw assembly.
(2)	The table (5A) which supports the gear case (2A5 for instruments Nos. 1-238 and 2RB for instruments Nos. 239 and up) containing the depression mechanism rides on the body (6B) bearing lightly on a circular track formed on the periphery of the body and also bearing on the table center (14L). A center screw (4H) permits adjustment to obtain minimum friction and minimum play on the circular track.
(3)	The mount is positioned on the pedestal cap (4A) by the ball (4J) and ball cap (4Y, sec. D-D, fig. 7). Three leveling screws (6N, fig. 1) threaded through the lower portion of the body (6B, figs. 1 and 7) bear on the upper surface of the pedestal cap.
(4)	The azimuth knob (17K, sec. E-E, fig. 7) rotates the table (5A, figs. 7 and 8) on the body. The table can be locked in any position by the table clamp knob (5D). Azimuth angles are ob-
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2	ORDNANCE DEPARTMENT
tained by aciding the indications, viewed through window (17C) of—
(a) The azimuth scale (14H) graduated at 10“-intervals, numbered from 0-35, the number coinciding or directly above the index mark being read.
(d)	The azimuth subscale (14A) graduated at 1°-intervals, numbered from 0-9, indicated on some portion of the subscale vernier.
(c)	The subscale vernier (14M) graduated at 0.01°-intervals, numbered from 0-100, read at the point where the subscale registers.
(5)	Two level assemblies (figs. 1, 5, and 7) are mounted on the table (5A).
(6)	The knurled sleeve on the rear tangent screw nut (figs. 6 and 10) operates the depression mechanism which controls the depression of the telescope for ranging. An internal gear train raises or lowers the front and rear tangent screw nuts simultaneously, inclining the telescope. The gear train also operates the range scale and the pointer which moves across the face of the range scale and indicates the range. A set of stop rings (13B) limits rotation of the tangent screw nut.
(7)	The slide block (sec. K-K, fig. 9), carrying the compensating screw and pin (3B) can be moved along the tangent screw rail (3UA, fig. 6) to compensate for variations in the height of the instrument above sea level. The height scale lies in a recess in the tangent screw rail and is read at an index on the rear surface of the slide block. The adjusting screw (3H) operated by the knob (3K, fig. 5) provides a fine adjusting motion for the slideblock. Clamping thumbscrews (22T, fig. 9) and gibs secure the slide block and adjusting screw nut (3N) to the tangent screw rail.
(8)	The compensating cam (fig. 6) operating through the compensating bar (sec. N-N, fig. 9) and rack (3NA, sec. L-L, fig. 9) drives the pinion (3V) which rotates the compensating screw (sec. K-K, fig. 9). The motion applies exact correction to compensate for differences in effect of curvature of the earth and normal refraction which exist at any height except the initial height, which is the height above the sea for which the range scale is computed. The thumb--screw (22G) clamps the compensating screw to the pinion, and when released permits independent motion between these parts for initial setting.
(9)	The range scale, the azimuth scales, and the cross wires in the telescope are electrically illuminated. A portable lamp is furnished for illuminating the height scale. A snap switch (B16805, fig. 5) with binding posts is located on the table hub. The electrical equipment supplied with the instrument is described in paragraph 7.
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DEPRESSION POSITION FINDER Ml 907
d. Pedestal.— (1) The pedestal is a hollow column of cast iron having three feet and an accurately machined upper portion which receives the pedestal cap (4A, fig. 1).
(2) The pedestal cap (4A, figs. 1 and 7) is secured to the pedestal by three hexagon-head screws (22XA). The upper portion of the pedestal cap contains seats for the leveling ball (4J) and ball cap (4Y), and a copper-plated circular track for the leveling screw shoes (6M). A 0.5-inch diameter hole is provided to receive an adjusting pin for turning the cap on the pedestal head.
3. Operation.—a. To set up instrument.—(1) Bolt the pedestal securely to the floor or foundation. Provide three small blocks of wood about 1 inch thick and place them on the pedestal cap. Set the mount on the blocks and start the ball cap (4Y) into the threads in the pedestal cap. Screw the leveling screws (6N) through the tapped holes in the lower part of the body and into the leveling screw shoes (6M) to transfer the weight of the body from the wood blocks to the leveling screws. Remove the wood blocks, lower the mount, and screw down the ball cap, using the adjusting pin provided.
(2) To mount the telescope in the yoke (5F), adjust the trunnions (5C) to support the telescope, allowing free rotation with no side play. An open-end engineer’s wrench is provided for the trunnion clamping screws. Adjust the counterweight assembly (B129215) until there is light but positive contact between the body tube bar and the compensating screw pin.
(3) Select a datum point of known azimuth. Turn the table by rotating the azimuth knob until the known azimuth is indicated on the azimuth dials, then clamp the table to the body of the instrument. Loosen the three pedestal cap screws (22XA, fig. 1). Insert the large adjusting pin in the hole in the side of the pedestal cap (4A) and turn the cap until the vertical cross line in the telescope coincides with the datum point. This procedure may disturb the level of the instrument. Level again and check by sighting on the datum point. Repeat until a correct setting is obtained, then tighten the three pedestal cap screws.
b.	To level instrument.—All observations are made with the instrument accurately leveled. To level the instrument, set one of the levels parallel to two of the leveling screws and manipulate the leveling screws until the bubble in each level is central. At the final setting, each screw should be tight but not strained.
c.	To focus telescope.—(1) Focus the eyepiece by screwing it in or out until the reticle cross wires appear in sharp focus.
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(2)	Focus the objective for elimination of parallax by turning the focusing pinion knob until the image of an object in the field of view shows no apparent motion relative to the cross wires as the eye is shifted slightly up or down or from side to side. This focusing varies to some extent for objects at greatly different ranges and for this reason should be repeated during normal operation.
d.	To determine azimuth of target.—Azimuths are obtained by rotation of the table after the table clamping knob (5D) has been released. Final accurate setting should be made by means of the azimuth knob (17K). The azimuth is read on the azimuth scale (10° units), subscale (1° units), and vernier (.01° units) as described in paragraph 2) Turn the instrument 180° in azimuth.
(c) By means of the level adjusting nuts (16N, sec. F-F, fig. 7), return the level bubble halfway to its original central position. An adjusting pin is provided with the instrument to fit the pinholes in the adjusting nuts.
(<7) Relevel the instrument, rotate it 180°, and again note the position of the bubbles. Repeat the operation, if necessary, until the best possible adjustment is obtained.
(2)	Azimuth mechanism.—The azimuth indicating mechanism is in adjustment when the subscale moves freely, without backlash, and a graduation on the azimuth scale alines exactly with its index as the zero of the subscale matches the zero of the subscale vernier. To remove backlash or to adjust the scale settings, loosen slightly the two clamping screws (22PA, figs. 8 and 5). Turn the eccentric (14G) with a screw driver, either to take up backlash or to disengage the pinion. Avoid excessive tightening of the eccentric. Then the special screw (22F) may be turned to aline the subscale with the zero of the vernier when a graduation on the azimuth scale alines exactly with its index. This screw is located under the large fillister head screw (22UA) which is removed for adjustment.
(3)	Table center.—The table is supported at its outer edge by a circular track formed on the body and at its center by a shoulder on the table center (14L, sec. C-C, fig. 8, and sec. D-D, fig. 7). The center screw (4H) regulates the height of the center and the friction on the plate and is accessible after the yoke has been removed. If the center requires adjustment, remove the yoke and the three clamping screws (22WA, sec. D-D, fig. 7). Adjust the center screw, using
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'ubraryr W0MtN
TM 9-1685
DEPRESSION POSITION FINDER Ml 907	.	5-6
the T-handle socket wrench provided, until minimum friction and minimum play of the table on the body are obtained.
(4)	Range stop.—The range stop may be adjusted, if necessary, to permit travel to the maximum or minimum range. Turn the knurled knob of the rear tangent screw nut as far as it will go in the desired
• direction. Hold the collar located below the stop ring housing (13A, fig. 6) to keep it from falling and loosen the three headless cone point screws (22U). The knurled knob may then be turned until the desired range is obtained. Tighten the three screws. If the knurled knob moves stiffly it indicates that one of the screws has been screwed in too far.
(5)	Reticle.—If the reticle has been disturbed or replaced it should be adjusted as follows:
(a) Set fixture (No. 86, optical repair kit) or any other surface plate on pedestal (No. 85) and level with bench level (No. 73). Clamp the collimating telescope (No. 89), using suitable rings or guides, to the plate. Clamp the telescope M1907 to the plate, using the bar (18D) as reference surface.
(&)	Lay off a target having a long vertical line and two horizontal cross lines spaced a distance equal to the difference in heights between the collimating telescope (No. 89) and the telescope M1907. Line the target up with a plumb line.
(c) Lay the collimating telescope on its line on the target and adjust the reticle of telescope M1907, using the special screws (22X) in slotted holes, until the horizontal cross wire coincides with its line on the target.
( X /-------------
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a Lj::«.rL„ i—ssr-« _______COVER,PRISM HOUSING
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_____ tX:_____________________________________________________________1^7.	_______screw,fillister head
T_______________■__________________________125X7/3^
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I9E
'--SlT6™ "EAD	icr™EF'LL1STER HCAD—	J25 XW9’/I6LISTER HEAD 	----SCREW,FILLISTER HEAD
_______?*R	CLIP.SAFETT-------- BLOCK,FILLER------------ ----------PIN,DOWEL,.101X 7/l6
_______HOLDER, PRISM
section p-p_	»H	ra PD 4047
Figure 3.—Telescope, depression position finder, M1907—sectioned views.
_EYEPIECE,ASSEMBLY,15 POWER
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TM 9-1685
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ORDNANCE DEPARTMENT
CELL, LENS_______ _______TUBE.EYEPIECC
A36630	BI662O
_________CELL,OBJECTIVE	SCREW,FLAT HEAD 9G	086X5/32	---- SCREW, HEADLESS, FLAT 	_____SCREW, HEADLESS,FLAT
BCUXICC	BCUXICC
______SCREW,FILLISTER HEAD,SPECIAL	m
A36610	A	RING,RETAINING 	___EYEPIECE , ASSEMBLY,25 POWER
____RING	__RING,RETAINING	>zJ	|C \ \ \ ,| ;	A36627	C442I7 9AB	9A	> V ZtF X - z-1
__SUNSHADE	ADAPTER, OBJECTIVE	J	F"j	fl	IK- § f	9VA	'	/	/	/	/
I	/	/	/	(-J___HOLDER,AMBER FILTER
I.-4-i	/	/	/	/	n h	20N
rXI_____SCREW, SPECIAL	/	I /	/	RJ
IXP 22DA	/ / / /	FT,—r 71 _rtf? I	/ ■ rt- _STUD
/ / / /	A	22C
-y-.-r > f	r-T^--7-4J Hzj	--------------1 I 1 1-------- 7s nJ	SPRING, BELLEVILLE
{____ //// L- 20M
WyL'j i, sSg- / / 1	/ / / /	rM 1 V tv u _____filter,amber
I/11A	/ / /	/ 'I	i	A36635
I U j	/ / /	----HrTH'T-1 -
.	7	______' U U==	h/V/ S-
I k	-• // J /	'	-A44A/F ~~~ ~~~ ; _EYELENS
V ’	- 1 —r—1.--?-.	A3663I
fl, ■	J'	f" \	______CAP,EYEPIECE
------kv---------------------------x \—pINJOIXI|	z	p-J-1	*------I	/	\-		________SPACER,LENS
i., -| ’V	SCREW,FILLISTER	HEAD,SPECIAL M	A-___SHUTTER	A36632
li' - M-----22S	X	)■	I9P
.	.	A	/ x	_______________LENS,FIELD
|	-----s-V_____/_______WINDOW	A3663I
. ।—^*7	|9Q
.	I	\	?	BRACKET. RETICLE LAMP	-SECTION THRU 25 POWER EYEPIECE
*' /-	T	■	x	l9M
J?	Jill/ _ | LAMP, ELECTRIC 	x	x	RECEPTACLE, CANDELABRA, ASSEMBLY	SL FFVF
yiJ 4	^~7\ A43039	..	——IBI35538	------A3838I
4-A-A jy	,! liTAl	PIN, IOIXO85-\	-------- ■ ADAPTER, RECEPTACLE	SLEEVE
L-z - ' • z z ' v~ I1AI	\ r '	'n/ '9N	I A38380
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a 36637	rMn	FT-	/]
S^P.rtLT---	J til 7 A
SECTION Q-Q	fflA	' b	” '_ 'A"
COUNTERWEIGHT-
SECTION THRU LAMP BRACKET	X$X<' Z/C/'z z/VX//Art
SECTION R-R	RA PD 4043
Figure 4.—Telescope, depression position finder, M1907—sectioned views.
20
DEPRESSION POSITION FINDER Ml 907
TM 9-1685
7
21
SCREW. WOOD ------— BCQX3HE----------------.	.-------------------— /-ISmvYc?01”40 HEA------------- '	SCREW,FILLISTER head	\
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4----------------------J;	1 f Wx£ iv/tlxX a/ / —--------------------------------e
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||||l	''	BRACKET, LAMP
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Figure 5.—Mount, depression position finder, M1907—assembled views.
TM 9-1685
7
ORDNANCE DEPARTMENT
__SUPPORT,COMP£NSATlNG BaR	SCREW,T1L HEAD,SPECIAL
SCREw/x. ME AO, SPECIAL___________ 3PA________-pin,O69X')6 ISM	Z22R
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SCREW,HL HEAD,SPECIAL__________...	----PIN 069X.r7 13 N	/ /»25 X 7/32
22R	’	/ /_,
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£?^L,STE* HEA---------- / //rail tangent screw___________________________________________________________ V-'//
BCFX,0C	_____SHAFT,CAM	/ // 3UA	n
HCAD^PECIAL	ISA	/ // SCREW,FLAT HEAD______________
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A347I0	./	SCALE,HEIGHT— ,	~~~[ Jl	/;/'■
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SCREW, HO*LS,CONE POINT.SPEC £ S /	7 — S' A	—   L -	S' X* T ----------------------/''/-----NUT *TANGENT SCREW.FRONT
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SCREW.Ho'lS/ZONE POINT,SPEC4AL_/ V / V/ > V	NIT NfZ X N I	K . ^-3 A____________________— Xt// B5IC
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SCREW,TANGENT-------------X ~ Nl z \	/ mJ E/. I z>^.k ■ X ■ I r sX'	/,'// ISB
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GEAR .TANGENT SCREW—-------j SZ^ /X Sk	___________j’ S	\S~	/^Z
screwz.lheaD—n	\	< yfy bcfx,dc
tMpSTxQii
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SUPPORT,INTERMEDIATE GEAR,	' GEAR,WORM SHAFT,UPPER—I	NUT.ROUNdJ	\\\IsTUDpNTERMEDIATE GEAR \\ SCREW.HEADLESS
Bl5iDTAPE'?-■------- PIN,.076 X I/O——J	\\\_SCREW,FILUSTER HEAD	\SCREW,FIL HEAD,SPECIAL
STUD,INTERMEDIATE GEAR_ OOIU	e^x«-r	\ \ BCGX2BF	22N
280	SUPPORT.WORM SHAFT--- ^FT.WORM---------	\ \_ SUPFORT.INTEPMEIXATE GEAR
SCREWTILLISTER HEAD ____ \ PAr
BGGX2BF	BUSHING_______________PIN,OOWEL,.l2XI/2	\—r FAR INTERMEDIATE	SECTION H ~ H
2BA	[GEAR,WORM SHAFT,LOWER	GEAR,INTERMEDIATE	pQ 4048
Figure 6.—Mount, depression position finder, M1907—sectioned views.
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TM 9-1685
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DEPRESSION POSITION FINDER Ml 90 7
___________NUT,ROUND
,•'/.	/ /	I6N
V/	zZ>	_________STUD .LEVEL	___________TUBE .LEVEL VIAL
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‘7/	7 7	I I6Q	F" A3I32I
__________________________SCREW, fX X'S.SFESIEL	1c !	’A ---- ----- !	i~ I 'c ■•/. nn ■''/	/ 22sa	pi	J
±	7//\—^pport’az,mu™9cale
/7 ZT^ ry ^17 '	____SCREW,FLAT HEAD
SCREW,CENTER	/z jS	'	BCKXIAB	PLASTER OF PARIS	SECTION F“F	PAPER FILLER
4H	---- N  ^^O^SCREW.nu.HEAD^PEC.AL	t^ZzM 7'7/7/^	h^"	W '1 I
__ - ’/z -----------------_SCTCTTZn--HEAD,SPECIAL	' ' ^X/ '‘sf'	1 fe - - ^ .1------------------------' SHOE .TABLE CLAMP z / . Ns \\ z Z-----------22ZA	Y I	T.PM-r.	U- -U-4L_r /□-5F
Z z\ IXx	X X <.♦ /	I z ,^A_______PIN .TAPER	1
Zz> kU----------//	\7 r A B5IB
Z/ Y 'zz	________,____K 4	--------------PIN,DOWEL,.125X3/8
-7-7T-.:-T	PIN,TAPER,3/BX3.	.SHAFT, PW.ON	SECTION G-G.
..........T?----------------W..,	...	|K| PINIONJNTFRMFDIATF TRAVERSING 777%------------------------'77777
r z 7 // //A	V ,/Zz Z,? z /«	/	"~ -VL // /^	\\________gear .traversing pinion
tZ-cXj________________________m]Z-T ZZZZjnIx z \
|z'Zl 1	/ rzll	77 l \___________SCREW,HEADLESS
Hz.zl______\	L_______\771	YXxV\ zry -ft	.099X7/32
\	/	rAPRAfi	I________________PINION .TRAVERSING
\	/	______CAP, BALL	I7H
77^~-------,	____________________HIT®
--------	--BALL	(7A
SECTION D-D	SECTION E~€	RA PD 4050
Figuek 7.—Mount, depression position finder, M1907—sectioned views.
23
TM 9-1685
7
ORDNANCE DEPARTMENT
24
SCREW .FLAT HEAD	______WINDOW
BCKXIAO	I7E
SUPPORT, RANGE SCALE GEAR	,__FRAME .WINDOW	----
I6F	ITO	A345S0
...................F 1 .zaif°
\	\___________._______________________________________________________bj-------1	\	|_GEAR,RANGE POINTER
oim nnuuci \	\	____GEARjRANGE SCALE	SUPPORT,RANGE POINTER GEAR	,6A
JZSXS^	\	l6E	,6B	_____GUIDE,POINTER
SCREW .FILLISTER HEAp\	——PIN,06 X 5/32	------SCALE,RANGE	PIN..06X1/4------------ l6L
BCGX3FF	PIVOT, RANGE SCALE GEAR	HUB^ANGE POINTER GEAR__	L-----HEA°
I6G	160	086 x 7/32
____________GUIDE,POINTER	PINION,RANGE POINTER_____ ______________POINTER,RANGE 16M	I6C______________________________________PIN,04 X 3/4
SECTION A-A_	--------SCREW.FILLISTER HEAD,SPECIAL	SECTION B-B
SCREW,FILLISTER HEAD.SPECIAL___________ _____________________§SS.n£LAT HEAD
22 UA	BCKX1AC
SCREW.FILLISTER HEAD,SPECIAL_________ SCREW.FILLISTER HEAD.SPECIAL-------------------------
22F	22K
SCREW, HEADLESS____________________ FRAME.WINDOW----------------------------------------
.073 X 7/32	■	178
ECCENTRIC_____________________ WINDOW-------------------------------------------------
MG	17c
SCREW.FILLISTER HEAD.SPECIAL_	BASKET------------------
22 PA	A34551
SUPPORT.SUB SCALE	VERNIER,SUB SCALE------------------ Z\-\
14 C	-------- \	I4M	_	---TABLE
' : U '	. . ;
SCREW.FILLISTER HEAD	HUB,SUB SCALE__________ I--------------------------?0DY
BCFX2AD	MF	6S
SCALE,SUB	BUSHING	__________SCREW.FILLISTER HEAD.SPECIAL
MA	ME	22GA
ADAPTER.SUB SCALE______ PINION_______________________ _______________________GEAR,AZINMTH SCALE SECTION C“C
14 8	14 D	,8G	------------—
RIVET____________________ KEY ________________________ _______________________.SCREW,FLAT HEAD	RA PD 4044
A39575	A39574	.086 X 5/32
Figure 8.—Mount, depression position finder, M1907—sectioned views.
TM 9-1685
7
DEPRESSION POSITION FINDER Ml 907
_________SCREW,FILLISTER HEAD
BCGX2BF
WHEEL WORM	_____BRACKET,WORM WHEEL SHAFT
I5D ’	\	2B
PIN ,TAPER__________ \	।
B 51D	\//. // / / //’y^.	Pl N__________________________
SCREW,HEADLESS___	Z^Z-/.Z 'Vy_£_ JXj _L Z ' Z *' xX	38	L
125X5/32	X. XI -ZJzj- X	V\	aj/Tp-p
e/ \	\ X'X	SCREW,COMPENSATING-------FT/ XA'3
\	/7z^x\	UA ./ffi.- A E3_THUMBSCREW
/ XXTXxZ> X \ XZvA	'	- — -4-—3"	22G
_ ...	_____\ L-K/ \¥A	PI N,DOWEL ,.076 X 5/8____H yV S _--------xJVXX \\____________________\ tA'X I /'X/	PINION,COMPENSATING SCREW_£3 Z /ITT v xuWh\ XZxx	3V________________________— T
/ ^^’Xx'xvV/ \	\	y^/^	BLOCK,SLIDE-------------—y /<|[\^
PINION,BEVEL__C^\ I A	gOrrWI—rt|
SHAFT, WORM WHEEL	^X/\	THUMBSCREW-----------k Xk
PIN JAPER,.04 X 275-^^^	I	G^B,SLIDE BLOCK-------------1
COLL AR____________X^
>5C	_______ . .	SECTION K-K
SECTION J-J	------------
,_____SHOE,RACK	----------P'N,DOWEL,.04 X 1/4
X. I	3P
।—ZCTVll	___SCREW,ADJUSTING
JXX\A_ 1 ____BUSHING,SLIDE BLOCK	I	3H
I—I 3YA	jl	.----BAR,COMPENSATING
RACK	r—PIN,DOWEL,.04 XI/8
3 NA	“	TyX
^Exw5>H3D?’cwEpo,N3-g	§fcx / • a	____NUT,ADJUSTING SCREW	______GUIDE,COMPENSATING BAR
3N	3QA
PIN,DOWEL,.04 X 3/16	________THUMBSCREW
YOKE,ADJUSTING SCREW_	22T
SCREW,FILLISTER HEAD_	SECTION M.-.M.	SECTION N7N.
BCFXIDO
SECTION L- L .	RA PD 4049
Figure 9.—Mount, depression position finder, M1907—sectioned views.
25
TM 9-1685
7
ORDNANCE DEPARTMENT
1---I-"T
!	!	PIN, STGHT
p^38	’ [fiOi	F201 x
y jn-o.-■.OJ.F^7pF' .W.^.,. P™ SCREW, HDLSS, FLAT	SCREW. HDLSS. FLAT	i ■ -O' i I \/’/ ////X Y///'//^/A
,25x®	p*&	r—BJz/W
KNOB ' £ P	A4660S	Y"' Ay/LA	I	?J M
A46609	5= ,V / /7C''/=S>rJ	', X /]/' ''7	TH	N V
- Bz	Yy7 I |
(fl/ W liS
/ \ /.'J \/	SECTION T-T	__ JEt_^4-
< ZP/S<	P'Z// '■<	CASE. GEAR. 2RB	77/ /N
Z ^ /* \ /	/ ' v /	row ftAK t W	\ J Y/^
C.’///Z/// /?.- \ y* \ /7/ <’/ ■’7/]	/	k /PZ7/.'’7 / 7	C0VER — 
4 Z/rr^mv *077 ^vfivzf'ii<	*4660? sections-s
Tl NylPzmKxl[■ J	'	_____I 'll K\pXNjtli	/	es«_aASJi_»M
2____________________ I ________________ZZL___________2
SCREW	GEAR	SCREW,_	L.GEAR
BCFXIDC	A466I2	BCFXIDC	A466I2
WASHES_ __________PIN, STGHT	WASHER_	PIN. STGNT
BEAXID	£ x J_	BEAXIO	£ x £
NUT ______ 84	NUT ____ 8 4
A466II	______SCREW	A 46611	______SCREW
A466I0	A466I0
PARTIAL SECTION H-H
RA PO 4041
Figure 10.—Mount, depression position finder, M1907 (class G only)—sectioned views.
26
DEPRESSION POSITION FINDER Ml 9 07
TM 9-1685
Appendix
LIST OF REFERENCES
1.	Standard Nomenclature Lists.
Finder, depression position, M1907------------SNL F—45.
Optical repair kit for harbor defense---------SNL F-93.
An up-to-date list of SNL’s is maintained as the “Ordnance Publication for Supply Index”------- OPSI.
2.	Technical Manuals.
Cleaning and preserving materials--------------TM 9-850
(now published as TR 1395-A)
Materiel inspection and repair-----------------TM 9-1100.
3.	Field Manuals.
Gunnery, seacoast artillery---------------------FM 4-10.
Fire control and position finding, seacoast artillery- FM 4-15. [A. G. 062.11 (8-7-41).]
By order of the Secretary of War:
G. C. MARSHALL, Chief of Staff. Official :
E. S. ADAMS,
Major General, The Adjutant General.
Distribution :
B 4 (2); IR 4 (3); IBn 9 (2); IC 9 (4).
(For explanation of symbols see FM 21-6.)
27
U. S. GOVERNMENT PRINTING OFFICE: 1»41
For sale by the Superintendent of Documents, Washington, D. C.
UNT LIBRARIES DENTON TX 76203
001895663