[Ordnance Maintenance]
[From the U.S. Government Publishing Office, www.gpo.gov]
WAR DEPARTMENT
TECHNICAL MANUAL
ORDNANCE MAINTENANCE
March 10, 1942
Document Reserve
37-MM GUN MATERIEL (TANK) M5 AND M6
NTSU LIBRARY
TM 9-1250
NON-CIRCULATING
9-1250
C 2
TECHNICAL MANUAL
ORDNANCE MAINTENANCE
37-MM GUN MATERIEL (TANK) M5 AND MG
Changes 1
No. 2 /
WAR DEPARTMENT, Washington, October 10, 1942.
TM 9-1250, March 10, 1942,“ is changed as follows: 3. Data.
* * * * *
Muzzle velocity, approx_ft. per sec._.
*****
Shot, AP, capped, M51_ft. per sec._ [A. G. 062.11 (9-10-42).] (C 2, Oct. 10, 1942.)
*
♦
*
2900
*
2900
486461’—42
NTSU LIBRARY
2
TM 9-1250
ORDNANCE MAINTENANCE - 0 2
Interval o Lubricant Lubricant • Interval . OE Gun bore (Note 7) OE < // RH Recoil mechanism RH
/ (Note 3) \\
/ / Upper and lower OE 0 \ \
/ / trunnions \ \ L.
/ / Cradle trunnion brgs. OE D \ \ \
/ / Recoil slides (Note 6) OE \\ \ \
/ / , P CG Rotor shields \\\ \ \
/ / / (Coat surfaces) \\\ • \ ■
/ / / / OE Recoil slides (Note 6) \\ \ \ fL
/ / / //M 06 Cylinder anchor pin \\ \ [N
r / /// 30 Cal. firing 06 M. \\\ \
/ / cable ends \ \\\ ,11,
/ / / / (M19, M20, M22) \ \\\ £3
/ // /M OG Gear case hub \ \\\ —
/// bearing (Sparingly) \ \\\
J / / / / / Stabilizer shaft brgs. OG M. \ \ \ \
y / (M23 and some M22) \ \\\\.
L\|/y / / l /M Ch Worm and wheel \ \ VXidu l|U
LL / / // / (Removecover,coat \ \A-A Vi_________________________
f, ----------'/ /\~~]/ / / Cyl. support brgs. 06 Mx \(\\ \\ ‘ \
/~7J~T / (M23 and some M22) \ VHSSW®
fl^7 U /rXv / M OE Piston rod bearing fekuJvLLlf
----ILL li^akW* BElevating rack and OE 0 \ \]n\ML&‘iF
WBltfllli worm (Note 4)
L-L—Elevating handwheel OE 0-^.
'HL m ~L~ shaft bearings "^^^1 '
jlLLi l? — Elevating cross
| u ix. shaft bearings i VK?” £?>
J____ 37 mm firing 06 M----1 ~I~~rLTU-L
I IJ c cable ends ^-O
a3 (M19, M20, M22) /W
w_„ ——I OH Hydraulic oil res. / A
\ (Remove cap, keep / / \Z-~,—j I
\ 3/4 full) / / LUJ /
\ Actuator plunger OE 0 / / L /
\ (M23) / / '‘-Z
\ Traversing rack and OE 0 ./ /
\ pinion (Note 4) / /
\ Hydraulic oil res. OH /
\ (Remove cap, keep / \ % full) /
GUN, 37-mm, M6 D 0E Breeth . and fifin9 0E 3 GUN, 37-mm, MS
MOUNT, M24 mechanism (Note5) MOUNT, Ml?. M2O, M22.
AND GUN, 37-mm, MS
MOUNT, M23
_____________________________ —KEY-_____________________ ____________
LUBRICANTS INTERVALS [
OE—OIL, engine OG—GREASE, O.D. D—DAILY
SAE 30 (above+32°) No. 0 (above+32°)
SAE 10 (below +32°) No. 00 (below +32°) M—MONTHLY
RH—OIL, recoil, heavy OH—OIL, hydraulic
RA PD 35437
Figubk 14.—Lubrication guide No. 58.
Notes.—Additional lubrication and service Instructions on individual units and parts (cold weather ; For lubrication and service below —10°, refer to OFSB 6-5).
TM 9-1250
37-MM GUN MATERIEL (TANK) M5 AND M6 C 2
1. Fittings and oilers.—Clean before applying lubricant. Where bearings can be seen, lubricate fittings until new grease is forced from the bearing.
2. Intervals.—The intervals indicated on lubrication guide are for normal service. For extreme conditions of heat, dust, etc., reduce intervals on guide by Vs or %, or more if conditions warrant.
3. Recoil fluid.—For instructions on quantity and application of recoil fluid, refer to War Department Recoil Fluid Guide No. 19 and OFSB fl-6.
4. Traversing and. elevating racks and pinions.-—Clean and apply oil, engine, seasonal grade, daily. Mounts M23 (except on light M3 tanks) and M24 do not have a traversing rack.
5. Breech and firing mechanism.—Clean and oil all moving parts and exposed metal surfaces with oil, engine, seasonal grade, daily. Perform operation before and after firing. Caution.—To insure easy breech operation and to avoid misfiring in cold weather, clean with solvent, dry-cleaning, dry and lubricate with oil, lubricating, for aircraft instruments and machine guns. To clean firing mechanism, remove and operate pin in solvent, dry-cleaning.
6. Recoil slides (37-mm); gun tube (75-mm).—At least once each week, lubricate recoil slides on 37-mm; remove locking key located below breech, retract gun and apply oil, engine, seasonal grade, to slides, Clean and oil exposed finished metal surface of gun tube on 75-mm daily and before firing; keep surface covered with thin film of oil, engine, seasonal grade.
7. Gun bore.—Clean and coat with oil, engine, seasonal grade, after firing. Inspect daily and oil if necessary.
8. Oil can points.—Lubricate the following points weekly with oil, engine, seasonal grade: (75-mm, all models) handwheel handles, firing button, firing lever link; (37-mm, all models) breech operating handle latch, elevating handwheel handle, firing plungers; (37-mm, M19, M20, M22) traversing bar surfaces.
9. Points to be lubricated by ordnance maintenance personnel at time of ordnance inspection.— (37-mm, mount M24) sight and gun rotor bearings, elevating gear case; (75-mm, all models) rotor bearings, cradle trunnion bearings, traversing and elevating gear cases; (37-mm and 75-mm, some models) gun stabilizer and turret traversing mechanism.
[A. G. 062.11 (0-10-42).] (C 2, Oct. 10, 1S42.)
By order of the Secretary of War :
G. 0- MARSHALL,
Chief of Staff.
Official :
J. A. ULIO,
Major General,
The Adjutant General.
3
U. S. GOVERNMENT POINTING OFFICE. 1942
TM 9-1250
1—2
TECHNICAL MANUAL No. 9-1250
WAR DEPARTMENT, Washington, March 10, 1942.
ORDNANCE MAINTENANCE
37-MM GUN MATERIEL (TANK) M5 AND M6
Prepared under direction of the Chief of Ordnance
Paragraphs
Section I. Introduction__________________________________________ 1
II. Description_____________________________________ 2-3
III. Inspection________________________________________ 4-7
IV. Maintenance and repair_________________________ 8-10
V. Care and preservation___________________________ 11-13
VI. References______________________________________ 14-15
Pages
Index________________________________________________________ 25-27
Section I
INTRODUCTION
Paragraph
Scope------------------------------------------------- 1
1. Scope.—This manual is published for the information and guidance of ordnance maintenance personnel. It contains detailed instructions for inspection, disassembly, assembly, maintenance, and repair of the 37-mm gun materiel (tank) M5 and M6, supplementary to those in the Field and Technical Manuals prepared for the using arm. Additional descriptive matter and illustrations are included to aid in providing a complete working knowledge of the materiel. For disassembly and assembly of the guns and filling of the recoil cylinder, see FM 23-80 and FM 23-81.
Section II
DESCRIPTION
Paragraph
General____________1_____________________________________________ 2
Data_____________________________________________________________ 3
2. General.—a. Guns.—The 37-mm tank guns M5 and M6 are flat trajectory weapons of the field gun type, single shot, with drop type
1
TM 9-1250
2—5
ORDNANCE MAINTENANCE
breechblocks. They fire projectiles which weigh about two pounds. The M6 gun has an automatic breechblock and is provided with a breech operating mechanism.
b. Recoil mechanisms.—Two types of recoil mechanisms are used, long and short. The mechanisms are substantially the same except for the following differences:
(1) Long recoil mechanism, drawing number D37256 (M5, early manufacture) :
A163742: Recoil spring.
C66643: Piston and rod.
A163951: Separator.
(2) Short recoil mechanism, drawing number D37844 (M5) : A186410: Recoil spring.
C73865 : Piston and rod.
(3) Short recoil mechanism, drawing number D47424 (M6) : A186410: Recoil spring.
C73865: Piston and rod.
3. Data.
M5 M6
Length of tube, approx--------------------------inches— 73 78
Weight of tube, assembly, approx----------------pounds— 185 ---
Weight of tube, assembly and breech operating mechanism—do-- 196
Muzzle velocity, approx----------------------ft. per sec—--- ------
Shell, fixed, AP, M51 and practice_____________do--- 2550 2550
Shell, fixed, HE, Mk. II_______________________do--- 2700 2700
Shell, fixed, HE, M63_________________________ do-- 2650 2650
Section III
INSPECTION
Paragraph
General----------------------------------------------------------- 4
Tools for inspection______________:------------------------------- 5
Cleaning and oiling----------------------------------------------- 6
Inspection-------------------------------------------------------- ?
4. General.—a. The purpose of inspection is to determine the condition of the materiel and the repairs or adjustments necessary to maintain the materiel in serviceable condition.
b. The procedure to be followed relative to inspection and maintenance is covered in TM 9-1100, “Ordnance Maintenance Procedure— Materiel Inspection and Repair."
5. Tools for inspection.—Such tools as may be needed for disassembling the gun for inspection may be obtained from the small arms repair truck. See the list of special repair tools listed in SNL A-35 and the tools listed in SNL G-72.
2
TM 9-1250
3 7-MM GUN MATERIEL (TANK) M5 AND M6 6-7
6. Cleaning and oiling.—Before proceeding with the inspection, clean and oil the gun properly in accordance with instructions given in paragraphs 12 and 13. This is highly important because some malfunctions may be caused by improper lubrication and the presence of dirt, grit, or other extraneous matter on surfaces or in recesses of operating parts.
7. Inspection.—a. General.—Inspection of the various parts of the gun and recoil mechanism should be carried out in the order listed. Unless otherwise indicated, the instructions are applicable to both types of guns and recoil mechanisms.
b. Gun as a unit (figs. 1 and 2).—(1) Note general appearance and missing or broken parts on exterior of gun.
(2) Check if gun is properly secured to yoke by means of fixed collar and threaded nut. Note if keys engage mating keyways on sides of gun and prevent it from turning (fig. 3). Check tube for looseness, and check breech ring locking key and screw for wear or damage.
(3) Open and close breech several times and check for sluggish movement and incomplete opening or closing. In M6 gun note failure of breechblock to stay in open position.
(4) Load gun with an empty case, open breech smartly, and note any difficulty or failure to extract and eject.
c. Breechblock group (fig. 4).— (1) Remove breechblock and carefully examine all exterior surfaces for burs, scores, or excessive wear. Pay particular attention to the surfaces which cam the extractors. In M6 gun, check also for burs on shoulders which bear against the extractors when block is in open position. Note if firing spring retainer pin is flush with U-shaped top face of breechblock.
(2) Examine front face of breechblock bushing for erosion and wear and note condition of firing pin hole. Measure diameter of firing pin hole. Diameter of firing pin hole is 0.175 + 0.004 inch. Note protrusion, if any, of firing pin from front face of breechblock bushing. Check if bushing is flush with front face of breechblock. Test for looseness of threaded joint between breechblock and bushing.
(3) Rotate upper arm of cocking lever forward and check for any sluggish movement or binding. Next, check if round end of cocking lever plunger bears against lower arm of cocking lever and holds it in most forward position possible. Note burs on cocking lever pivot and its recess. Examine plunger for burs and for obstructions of air channel. Test tension of plunger spring. Check for dirt and other extraneous matter in plunger recess.
3
4
— BREECHBLOCK
BREECH RING T.
—I
SSI ' ” B?
WiHMK?'/ w 1------5—---SLEIGH
-----RECOIL CYLINDER _ A
1--BREECH OPERATING MECHANISM RA PD 9956
Figure 1.—37-mm gun (tank) M6—right side view with breech operating mechanism assembled.
^SSSSSo
■„ 4, y • ' ' / riiMiiifiFtwawiiiwIg
%fgf Tt, Ws^ <^^^*wKwgg>sw;।
CLOSING SPRING ASSEMBLY-!
RA PD 9957
Figure 2.—37-mm gun (tank) M6—left side view with breechlock to open position.
TM 9-1250
7 ORDNANCE MAINTENANCE
3 7-MM GUN MATERIEL
TM
(TANK) M5 AND M6
>-1250
7
5
RA RD 5911
Figure 3.—37-mm gun (tank) M6—sleigh.
TM 9-1250
7 ORDNANCE MAINTENANCE
x-J &--SEAR LOCK
i
COCK.NG LEVER / I1’ A^-WSSHER
COCKING LEVER ^A^flL if III /L:. ' J \^S~'7ill
PLUNGER SPRING [F' (\ ^^Sy I
COCKING /j/ / >8 FIRING PIN
LEVER 'Al S' f /f/7/S ~ "* j /
/ 1 III I y!i " x-^^- FIRING SPRING
y Ffj I •H & 1 % xny.r^ \[l|lr SPRING lx_^ FIRING SPRING RETAINER—J
Ijl RAPO 5668
Figure 4.—37-mm gun (tank) M6—breechblock assembly—parts.
6
TM 9-1250
(TANK) M5 AND M6
7
3 7-MM GUN MATERIEL
7
SPRING - FAAX1F TRIGGER - B8446 PLUNGER - A25205
/ ■ -.-"-I.-- I w
/ .L ■ M
mwi Ml Ji WTW Jal
I ’.I
PLUNGER ■ A25209 SPRING - A25206 SPRING • FAAX1F ■--SEAR 8,8,908
I X F’
LEVER ■ B171690-1 W
® LOCK - A217392
» I O-----WASHER - A217391
EXTRACTOR - B171698A
TRIPPER - B181909
, , < j — EXTRACTOR - B171698B
n
STOP ■ Al 96350
-.......................a ..................... 1 J L M fet
< ^iRIr r,^-r.,K,ro GUIDE ■ C77527—
— RETAINER - B8444 ‘0 |
SPRING - A25204 PIN • A25201 9^ RA RD 5908
Figure 5.—37-nim gun (tank) M6—breech mechanism—parts.
TM 9-1250
7
ORDNANCE MAINTENANCE
COCKING LEVER
.. .. ''
ring—a a a a MB Jflr / fr^^k Bilililll il fc£ 7®" -- 1-BREECH BLOCK
FIRING PIN-JflSfl|fl|MflMF i / 1
RETAINER
LEVER ARM SHAFT—xg| ••“ fl
11 PrfW:: RRr- tr,cger
LINK-\ f |s |
I I I / |L_
. ' /'
HOUSING-^ SPRING-xR0D’\ ’X Z^‘*%JHM|
ryMZ~Xgm£.<> V ’X I.......................................-...
-.'. ix-.L ' [
»• • • ~w iz... _ .
_ AMBm^...._
: ■ " | ............................
L BREECH OPERATING MECHANISM OPERATING CRANK”1 RA PD 5680
Figure 6.—37-mm sun (tank) M6—sectional view of breech mechanism.
8
TM 9-1250
37-MM GUN MATERIEL
(TANK) Mo AND M6 7
pin-' y\ -—-----
^LEVER ARM SHAFT^^8^^ ' I ' E;
..
----
TRIGGER PLUNGER SPRING --
TRIGGER PLUNGER - \ t | O I -«TO-^)
W'^ EXTRACTOR PLUNGER^ \
/^ w«mu SPRING \
%/S^ M EXTRACTOR PLUNGER-*
'^\ I —TRIPPER
wv ^IL/”operating crank W
Vjgw ■ y [[k
\'h h JjA-7--EXTRACTOR
\ ®^n I/'u
M (®/fi
Aj/y RAPD 5667
f '*55^'
Figure 7.—37-mm gun (tank) M6—breech mechanism—parts w/o breechblock assembly.
484568°—42---2
9
TM 9-1250
7 ORDNANCE MAINTENANCE
(4) Press firing spring retainer about % °f an inch into breechblock and rotate left or right, noting any sluggish movement or binding. Remove retainer and look for burs and scores on outside and inside surfaces. Pay particular attention to the seat for the retainer pin. Note any dents or deformation of front edges (fig. 5).
(5) Remove firing spring and examine for distortions and free length. Free length of spring is approximately 2% inches.
(6) Remove firing pin guide assembly, noting freedom of guide in guide chamber. Test freedom of stop in guide. See if firing pin guide pin is flush with sides of guide.
(7) Disassemble guide assembly. Examine guide for straightness and burs, particularly on surfaces of sear lug. Examine threads in guide for wear or damage. Check the stop for burs and deformations. Test tension of firing pin retracting spring. Free length is approximately 1% inches. Examine firing pin for worn or damaged threads and for burs, deformations, pitting, or indications of fracture on striker end.
(8) Remove the sear retaining pin (M5 gun) and sear retaining lock and washer (M6 gun) and examine for damage. Test tension of sear spring. Examine the sear carefully for burs and scores, particularly on flat'surfaces and edges which contact the sear lug and guide.
(9) Note any burs or irregularities in guide chamber in breechblock. Check the protrusion of retainer pin into guide chamber. Lower end of retainer pin should be about 0.002 to 0.004 inch above that of the interrupted shoulder in guide chamber.
d. Breech ring group (figs. 6 and 7).— (1) Actuate the trigger and note functioning of trigger plunger. Remove tripper, noting freedom in hub of trigger. Examine tripper for burs or rough surfaces and indications of fracture.
(2) Remove trigger, and trigger plunger and spring. Examine trigger for burs and signs of fracture. Test tension of trigger plunger spring. Check trigger plunger for burs and obstructions in vents.
(3) Remove extractors and examine for burs and wear on camming surfaces, lips of upper arms, and in pivoting holes. Look for signs of fracture. In M6 gun, look for burs on lower flat ends of extractors and at edges.
(4) Check for burs and rough surfaces on extractor pivots. Test if pivots are firmly pressed into ring.
(5) Test functioning of extractor plungers (M6 gun). See if air channels in plungers are clear.
10
TM 9-1250
37-MM GUN MATERIEL (TANK) M5 AND M6 7
11
z—CATCH-BI58577
^^^^^/z-SCREW-BCFX2FK
PIN-BFDX2CC
LATCH-B8437-------t---------
SPRING-A25207-----
HANDLE-070430----^rO------------A-AlC_-==^-----CRANK-B8439
® \Q=^
\ \
I J
--PIVOT-A2S2O0
4Wmr i, z J1' >' L_21m4tI-PIN-BFDXIBF
SPRING-FAAXIF-------/x^" U "----EXTRACT0R.R.H.-B844IB
SE AR-B8445--------■ ~- f ! ■ I -
PIN-BFDXIES------^—EXTRACTOR,L.H.- B844IA
BREECHBL0CK-D36225/^;"--, ;
/-RETAINER-68444
SPRING-A25206----—SPRING-A252O4
LEVER-68443-------I — PIN - A 25201
PLUNGER-A25205---—””---------------------------SPRING-FAAXIF
GUIDE-A25200-----------------------------------PLUNGER-A25209
SPRING-A25202-----— t=;r:+^J|L W —TRIGGER-88446
ST0P-A25203---------—TRIPPER-B8447
BUSHING-A25I99---C < ^^^DETENT-A252I3
-----NUT-BBSX4G
4k < ” JU—KEY-A252I5
Ifeap__________H--------z
RA FSD 508
Figure 8.—37-mm gun (tank) M5—breech mechanism assembly.
TM 9-1250
7
ORDNANCE MAINTENANCE
fj '
SPRING -' A196330 ■■■■■■■- 8^9^
PIN - Al 96333 ...^
1 CM' ^..» o EE,K^Z^==s® ©J
® ’»»“p®“Wi’ «=«»p ■"■ W
LINK - A196331 11 crin I.,.™. I
T ROD - B171691 NUT . A196326
PIN - A217385 BREECHBLOCK - D36198
fS®!!
nB^ggiB ' ' wW ®
f-CRANK ASSEMBLY - C77526 » !SbB
' !'■ t Bl
W a t Ue
i i .. ®| \ btSI I
■ I I-SHAFT - B171692 I B Ijr I
I *
WMHBB^' A 7 '
<4as>, RA pD 59O7
Figure 9.—37-mm gun (tank) M6—breech mechanism—parts.
12
TM 9-1250
AMd STATE CULLtUu tOk WUMEK
LIBRARY
3 7-MM GUN MATERIEL (TANK) M5 AND M6 7
(6) Examine breech recess for burs, scores, dirt, and other extraneous matter on bearing surfaces.
(7) Note if cocking pin is damaged and cocking pin screw is flush with rear face of breech ring (M6 gun).
e. Breechblock operating group (M5gun) (fig. 8).— (1) Rotate operating handle to most forward position and see if operating handle lever latches.
(2) Test tension of operating handle latch spring. Free height of spring is approximately 1% inches.
(3) Check if operating handle lever and shaft are firmly welded together. Examine splines of shaft for damage and test firmness of spot weld on left end of splined hub.
(4) Examine crank for burs on trunnions and damage to splines.
(5) Examine operating handle detent for deformations or signs of fracture.
f. Crank assembly (M6 gun).—Examine crank assembly for signs of fracture and defective welding between crank pin, handle web, and crank. Check for burs in pivoting hole and on crank lug and trunnions.
g. Closing spring and housing group (M6 gun) (fig. 9).— (1) Note if housing body is firmly attached to breech ring. Housing body screw should be tight, with the cut end alined with circumference of breech ring.
(2) Unscrew the housing, noting any binding between housing and closing spring rod nut. Examine housing for dents or irregularities inside.
(3) Note if closing spring retainer is positioned properly. Flanged end of retainer should bear against spring. Test tension of spring. Free length of spring is approximately 6.86 inches.
(4) Examine closing spring rod for straightness. Note any binding between rod and lever arm shaft link. Dirt may enter through slot in housing body and cause binding. Link pin should be staked. Note wear of locking slot in link.
(5) Remove housing body and see if housing body pin is in position.
(6) Check closing spring locking pin for excessive wear and signs of fracture.
(7) Examine lever arm shaft for rust or rough surfaces, particularly on lugs which fit into mating slots in hub of crank assembly.
h. Tube.—(1) Check for burs in extractor pockets, in chamber, and on bearing surfaces on exterior of tube.
(2) Examine the bore visually from both ends and note sharpness of lands, carbon deposits, powder fouling, rust, and coppering.
13
TM 9-1250
7
ORDNANCE MAINTENANCE
i. Breech operating mechanism (M6 gun) (fig. 10).— (1) Note general condition of mechanism. Examine for rust and scale on camming surfaces of the crank cam and guide. Examine mating guideway for breech ring guide for scale and irregularities.
(2) Test functioning of cam retaining plunger. With a tapered pin, depress the plunger as far as it will go and, at the same time, push the cam slightly forward. Release the pressure and push the cam forward until cam retaining screw is in the adjacent screw hole. Remove the cam and note if plunger bushing is staked. Remove the bushing and plunger. Examine plunger for straightness. Test tension of plunger spring.
j. Recoil mechanism (fig. 11).— (1) Examine recoil cylinder carefully for indications of oil leakage.
(2) Uncouple the gun. Drain the recoil cylinder. Disassemble the recoil mechanism as follows: remove the front head with buffer attached. Insert the spacer on the buffer between head and piston and reassemble the head. Remove the pin which secures the coupler to the piston rod, then remove the coupler, washer, and follower. Attach the puller and place a bar through the eye on the puller. With a man on each end of the bar, keep the springs under compression while the front head is removed. Gradually release the spring pressure. Unscrew the eye of the puller and remove the piston and rod and the springs. Remove end of puller from piston rod (fig. 12).
(3) Examine the recoil cylinder and piston and rod for corrosion (fig- 13).
(4) Test tension of valve and recoil springs. Free height of recoil spring in short cylinder is approximately 29.9 inches. Free height of each recoil spring in long cylinder is approximately 26.45 inches. Free height of valve spring is approximately 3.74 inches.
(5) Test valve nut for looseness and measure the valve lift. Valve lift is 0.022 inch. Measure thickness of valve collar. Normal thickness is 0.187 inch and is determined by trial.
(6) Examine leather packing for distortion, wear, and hardness. Packing is of chrome leather and paraffin dipped, but it should be inspected carefully and frequently.
(7) Remove the copper gaskets at each end of recoil cylinder and examine for hardness.
(8) Test for looseness of threaded joint between housing and gland follower. Gland follower should be staked to housing. Housing washer should be secured tightly to the coupler.
14
TM 9-1250
3 7-MM GUN MATERIEL (TANK) M5 AND M6 7
. /-SCREW - AI96338 _/-BOLT - A2I7393 J-( ' I { j I : 1
■MM,_______________ jil ;fn , , ij
। /| , p-------\ _ .jJ [ J [
p——-----------p———n
______________________ _____________ ' -. -1 /- .... ~t 1 ~ —_____________________J
4, / V ( y ( 1Y,( \ J \ r-BRACKET - C77508
iw ... —‘—x ——vfKxU X\/
xIt'- 1
I LLp|N . a 196349
“-BUSHING - A196348
-SPRING - AI96347 CAM - BI7I694“-GUIDE - AI96328 RA PD 5910
FIGURE vO.—37-mm gun (tank) M6—breech operating mechanism.
15
TM 9-1250
7 ORDNANCE MAINTENANCE
---PLUS - A168704
----LINK - A168702
■—GASKET - A168098
/ r— LINK - Al68703
/ / i—BUFFER - A163949 ---
/ / J GASKET - A168098
/ / — —DETERMINE BY TRIAL (NORMAL THICKNESS = .187) | PLUS • A168097
I / -I-.022 VALVE LIFT L------67s MIN. TO 8 MAX. RECOIL -------- FOLLOWER - Bl 5376^-
/ / W' 4 ’TZZZZZ^WZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ.'///////// /////////////.^ 'KKfa
" i E---------------------------------------
' y]T 7~r' z/7zzzz z'^7 >zz///zzz////ZZZ///Z2z/zzzzz//zzz.z^zz zZZ Z +
/ L VALVE . A163950 '-CYLINDER, RECOIL - D47422 HOUSING - 8153760-^/// /
\ L SPRING, HELICAL - A165976 PACKING - A163952 /
j —COLLAR - AI70084 Lp|STON AND ROD . C73g65 GLAND - AI63953 —'/ /
/ —NUT - Al63948 GASKET - AI63947_____{
--------SCREW, SET SAFETY ■ BCTXIBB —SPRING - AI864I0 FOLLOWER - AI63954 L_ GASKET. AI63956 (STAKE TO LOCK)
I— HEAD - Bl 56653 WASHER ■ A163955------
----THONG - A17950 SCREW, MACH. - BCKXIDF--------
PIN • BEDXIEU-----
COUPLER - BI53762 -----
RA PD 5914
Figure 11.—37-inm gun (tank) M6—recoil mechanism.
16
TM 9-1250
3 7-MM GUN MATERIEL (TANK) M5 AND M6 7
17
VALVE - A16395O—j BUFFER - A163949 . PLUG - A168704—.
fes 'i lAAAAi A - ■-V-JUBri
yr v Mo® _Mw
/ v i ja
COLLAR - A170084-> SPRING - Al65976 ' NUT - A163948 -I HEAD - B156653 / J?
r"-""
■fl | I H a
COUPLER ■ B153762-* L FOLLOWER - B153761 *- GLAND - A163953 HOUSING - B153760 ' PLUG - A168097 —
RA PD 5913
Figure 12.—37-mm gun (tank) M6—recoil mechanism—parts.
18
TM 9-1250
7 ORDNANCE MAINTENANCE
PISTON AND ROD - C73865 ®
SPRING - A186410 (
.■■■_.. GG. CYLINDER - D47422 1L, I
JMBMMh ®®W _ ______
. y
. -. - \ . -- i _ __ —MB
■BHHHmHI^^^BHHHIv sHIMHMHmMIv BBW ra pd 5912 Figure 13.—37-mm gun (tank) M6—recoil mechanism—parts.
<
TM 9-1250
37-MM GUN MATERIEL (TANK) M5 AND M6 8-10
Section IV
MAINTENANCE AND REPAIR
Paragraph
General_____________________________________________________ 8
Special tools_______________________________________________ 9
Maintenance and repair_______________________________________ 10
8. General.—The maintenance and repair of the 37-mm tank guns M5 and M6 as covered in this manual is primarily a replacement of worn or broken parts. General assembly and disassembly of the guns are covered in EM 23-80 and FM 23-81.
9. Special tools.—Items comprising a set of special repair tools for the 37-mm tank guns M5 and M6, are listed in Section X of SNL A-35. Common tools are listed in SNL G-72. It is essential that only oilstones or very fine files be used in removing burs or rough surfaces.
10. Maintenance and repair.—a. Gun as a unit.—(1) Failure to extract.—Remove all burs and irregularities in chamber and deformations at edge of chamber. Replace broken extractors.
(2) Weak ejection.—Proceed as above and also remove any burs on camming surfaces of extractors and on breechblock. If the extractors bind on the pivots, lift off the extractors, remove all burs and rough spots on pivots and in extractor hubs, and then refit. In the case of the M6 gun, remove any burs from the round and flat surfaces on lower ends of extractors. Burs should also be removed from the shoulders on the sides of the breechblock (M6 gun) which support the extractors when breech is open.
(3) Sluggish movement of block ar failure to open or close fully.—
(a ) Remove all burs and rough spots from breechblock and extractors and from bearing surfaces in breech recess.
(Z>) In the case of the M6 gun, remove any rust or scale from crank cam and guide. Remove any dents on housing and straighten it if bent. If closing spring is distorted and binds the housing, replace the spring. If the breechblock fails to stay in open position, remove all burs on lower ends of extractors and on shoulders on which the extractors bear when breech is open.
b. Breechblock group (fig. 4).—(1) If breechblock bushing is not flush with front face of block, if threads between bushing and block are loose, or if firing pin hole is enlarged, replace the bushing. Drill two holes about 0.2 inch deep and about 1 inch apart on a center line of
19
TM 9-1250
10
ORDNANCE MAINTENANCE
front face of bushing. Insert a spanner wrench into the holes and unscrew the bushing. Chase out the threads in the block, if necessary. The threads are l^-16N-3. Screw in a new bushing and machine it flush with front face of breechblock. An alternate method of removing the bushing is to drive a cross-cut chisel or heavy center punch into the bushing face so as to rotate it counterclockwise.
(2) If cocking lever is rotated with difficulty, withdraw; remove all burs from its hub and recess, and refit. If the cocking lever plunger binds, withdraw it; clean the air channel, remove all rough spots, and refit. If the plunger does not bind but fails to retain the lower arm of cocking lever in most forward position possible, replace the plunger spring.
(3) Malfunctions of the firing mechanism may be due to a number of causes, such as damaged firing pin, binding between parts, and weak or broken springs. Remove and disassemble the mechanism. If the firing pin point is deformed, broken, or pitted, replace the firing pin. Remove all burs from the walls of the guide chamber in the breechblock and clean the chamber, being careful not to leave any foreign matter in the grooves. Remove all burs and irregularities from the guide, stop, and retainer. Pay particular attention to the sear lug on the guide and the seats for the retainer pin on the retainer. Replace the firing and retracting springs if they are broken, weak, or short of free length. The firing pin should never protrude beyond the breechblock face. If it does, replace the retracting spring.
(4) The threads in the guide and on the firing pin may be chased out, if necessary. The threads are %-24NF-3. If the threaded joint is too lose, replace the firing pin and/or guide.
(5) If sear fails to engage sear lug of guide, replace the sear spring. Remove any burs on contacting surfaces of sear. If gun fails to fire and there is no percussion mark on primer, replace the sear spring, firing spring, or firing pin.
c. Breech ring group (fig. 6).—(1) Remove any irregularities on breech ring guide. Remove all burs and rough spots and any extraneous matter from bearing surfaces in breech recess. If the trigger plunger binds or functions sluggishly, withdraw it, clean the vents on the plunger, remove any burs, and refit. If plunger spring is weak or broken, replace it. If trigger and tripper show signs of fracture, replace them.
(2) Failure of extractor plungers to function properly may be due to weak springs or plugged air channels. Remove the plungers, clean
20
TM 9-1250
3 7-MM GUN MATERIEL (TANK) M5 AND M6 10
the air channels, and refit. If necessary, replace the plunger springs.
(3) If extractor pivots are loose, new pivots should be pressed into the breech ring. In the M5 gun, each pivot is 1.66 inches long. In the M6 gun, the left-hand pivot is 1.31 inches long and the right-hand pivot is 1.66 inches long.
(4) If the cocking pin is broken, it should be replaced. Drill the cocking pin screw to a depth of about 0.5 inch, using a 5/32 drill. Remove the cocking pin screw with a screw remover. Insert a new cocking pin, flat end to the rear and wider shoulder to the left. Screw in the cocking pin screw, cut it off, and file it flush.
(5) Replace breech ring locking key and screw if loose or damaged.
d. Closing spring and housing group (M6 gun) (fig. 6).— (1) This group will ordinarily require very little repair. If the closing spring is weak, broken, or sufficiently distorted to bind in the housing, it should be replaced. Any dents in the housing should be removed and the housing straightened. If necessary, chase out the threads in the housing and housing body. The threads are 1.35-20NS-3. If the housing body screw is loose and damaged, replace it. The screw should be cut at assembly to clear the 4.75 inch diameter in the breech ring.
(2) Clean the housing body of all extraneous matter which might enter through the slot in the body and cause binding. If the lug on the closing spring locking pin is excessively worn or sheared off. replace the pin.
e. Tube.—There are no available data on gaging the tube, and all corrective measures must therefore be based on visual inspection. The bore should be cleaned and oiled in accordance with instructions given in paragraphs 12 and 13. The tube should be replaced if there are large pits and torn lands or excessive erosion at origin of rifling.
f. Breech operating machanism (]yi6 gun) (fig. 10).—Remove all dirt and scale from the camming surfaces of the crank cam.and guide. If cam retaining plunger does not function properly, replace the plunger spring and stake the plunger bushing. Remove any scale or irregularities from the mating guideway for the breech ring guide.
g. Breechblock operating group (M5 gun) (fig. 8).—Clean the splines on the hub of the operating handle shaft and in the crank. If operating handle lever does not latch, replace the latch spring. If operating handle detent shows signs of fracture, replace it.
h. Recoil mechanism (fig. 11).— (1) If there is leakage of oil from cylinder, tighten all threaded parts and plugs. If leakage continues,
21
TM 9-1250
10-11
ORDNANCE MAINTENANCE
replace gaskets. In removing gaskets, great care should be exercised to avoid damage to the gasket seat. If the soft copper gaskets at each end of the cylinder become hardened, they should be replaced. In an emergency, the hardened gaskets may be softened sufficiently for reuse by heating them to red heat and cooling in air or quenching. If the leather packing becomes hardened, replace it.
(2) The ring of antifriction metal on the piston forms an integral part of the piston. It may require occasional dressing, but if it is excessively worn or damaged beyond repair, replace the piston and rod.
(3) Slow and short recoil accompanied by excessive shock on the entire mechanism may be remedied by any of the following measures. Adjust (reduce) the amount of oil in the recoil cylinder to create a “void” which will compensate for expansion of the oil during firing. This procedure is also applicable if the gun fails to return completely into battery. Clean the valve and increase the valve lift to 0.022 inch by replacing the valve spring. A less desirable method is to back off the valve nut sufficiently to give a valve lift of 0.022 inch. If it is necessary to replace the valve collar, determine its thickness by trial (normal thickness is 0.187 inch). If recoil spring is short of free length, replace it.
(4) Fast and long recoil and excessive shock on mechanism may usually be remedied by refilling the cylinder with proper amount of oil. If necessary, reduce the valve lift to 0.022 inch by adjusting the valve nut on the piston. Replace the piston and rod if the antifriction piston ring is damaged beyond repair.
Section V
CARE AND PRESERVATION
' Paragraph
General----------------------------------------------------- 11
Cleaning---------------------------------------------------- 12
Lubrication------------------------------------------------- 13
11. General.—a. This section contains instructions for care and preservation of the weapon by ordnance maintenance companies and all other personnel charged with the maintenance of this materiel. Detailed information pertaining to cleaning, preserving, and lubricating materials will be found in TM 9-850. The use of materials other than those authorized for the purpose mentioned is strictly forbidden.
b. Dirt and grit which accumulate on gun and in operating mechanism settle on bearing surfaces. This dirt and grit in combination with
22
TM 9-1250
3 7-MM GUN MATERIEL (TANK) M5 AND M6 11-13
lubricant form a grinding compound. Powder fouling attracts moisture and hastens formation of rust. Therefore, the gun should be cleaned and lubricated before and after inspection and repair in order to eliminate malfunctions due to improper cleaning and oiling.
12. Cleaning.—a. General cleaning.—Dirt on nonbearing surfaces can usually be removed by water. Lubricated or other greasy parts must be cleaned with SOLVENT, dry-cleaning, applied with a rag.
b. Detailed cleaning.— (1) Bore and breech recess.—Remove breechblock and firing mechanism in breech ring. Thoroughly sluice and sponge bore and chamber with a solution of ^2 pound of SODA ASH in 1 gallon of water, hot water and issue soap, or hot water alone. In the absence of these, use cold water. Then swab the bore and chamber with dry waste or rags until they are perfectly dry. Inspect the bore and chamber for any remaining residue. If they are not clean, repeat rinsing and drying. A small piece of burlap used as a patch over the end of brush on rammer is effective for cleaning the bore. When all powder fouling has been removed, dry the bore and chamber thoroughly and cover with a light coat of lubricating oil. Whenever soda ash solution is used for cleaning, all parts cleaned should be swabbed or rinsed with clear water, and dried, before oiling. All parts, surfaces, and recesses should be thoroughly dried before they are oiled. The parts of the firing mechanism removed from the breech ring should be cleaned with a dry rag and then wiped with an oily rag.
(2) Breechblock.—With a dry rag, clean dirt and oil from the breechblock and all its parts. Lubricate all recesses for moving parts with light oil. Wipe with an oily rag, leaving a thin coating of oil.
(3) Outer surfaces of gun.—Clean outer surfaces, using a damp rag or dry-cleaning solvent when necessary. Dry and wipe all exposed metal parts with an oily rag. Do not apply oil to painted surfaces.
13. Lubrication.—a. Excessive wear and resulting malfunctions can be prevented by keeping the materiel clean and well lubricated. Apply sufficient lubrication but avoid excessive and wasteful use of lubricants. Lubricate all recesses of moving parts with light oil and maneuver moving parts to cause even distribution of lubricant. For temperatures below 32° F. use SAE 10W oil; for temperatures above 32° F. use SAE 2'0 oil.
b. In temperatures below freezing, it is necessary that moving parts be kept absolutely free from moisture. It has also been found that excess oil on working parts will solidify to such an extent as to cause sluggish operation or complete failure.
23
TM 9-1250
14-15
ORDNANCE MAINTENANCE
Section VI
REFERENCES
Paragraph
Standard Nomenclature Lists__________________________________ 14
Explanatory publications_____________________________________ 15
14. Standard Nomenclature Lists.
a. Ammunition.
Ammunition, fixed, all types, for pack, light, and medium
field artillery_________________________________________ SNL R-l
b. Cleaning, preserving and lubricating materials,
recoil fluids, special oils, and similar items of issue_ SNL K-l
Soldering, brazing, and welding material, gases and re-
lated items_______________________c_____________________ SNL K-2
c. Gun materiel.
Gun, 37-mm, M5 and M6___________________________________ SNL A-45
d. Repair.
Tools, maintenance, for repair of automatic guns, etc_ _ SNL A-35
Truck, small arms, repair, Ml___________________________ SNL G-72
15. Explanatory publications.
a. Ammunition, general_______________________________ TM 9-1900
b. Cleaning, preserving, lubricating and welding ma-
terials and similar items_______________________________ TM 9-850
c. Gun materiel.
37-mm gun, tank, M5_____________________________________ FM 23-80
37-mm gun, tank, M6_____________________________________ FM 23-81
d. Maintenance.
Ordnance maintenance procedure, materiel inspection
and repair______________________________________________ TM 9-1100
24
INDEX
A Page
Assembly of gun------------------ 19
15
Bore: cleaning of_______________________ 23
inspection of___________________ 23
Breechblock: bushing, replacing______________19-20
cleaning of_____________________ 23
described_______________________1-2
illustrated (M6)_______________ 4
Breechblock group: inspection of______________________ 3
maintenance and repair of______19-20
parts illustrated________________ 6
Breechblock operating group: inspection of___________________ 13
maintenance and repair of______ 21
Breech mechanism, illustrated:
M5______________________________ 11
M6________________________ 7,8,9,12
Breech operating mechanism: described__________________________ 2
illustrated (M6)______________4.15
inspection of___________________ 14
maintenance and repair of_______ 21
Breech recess, cleaning___________ 23
Breech ring group: inspection of__________________ 10-13
maintenance and repair of______20-21
Bushing, breechblock, replacing__19-20
C
Cam retaining plunger, inspection
of------------------------------ 14
Care and preservation of gun______22-23
Cleanin gof gun____________________ 23
before inspection_________________ 3
Page
Closing spring and housing group: free length of spring_____________ 13
inspection of------------------- 13
maintenance and repair of______ 21
Cocking lever: inspection of---------------------- 3
maintenance and repair of______ 20
Cocking pin, replacing____________ 21
Collar, valve, thickness of_______ 14
Crank assembly, inspection of___ 13
Cylinder, recoil: inspection of_____________________ 14
oil leakage from________________ 14
D
Data on guns_______________________ 2
Description of guns________________ 1
Disassembly of gun________________ 19
E
Extractors_____________________ 2-3,10
maintenance and repair of_______ 19
replacing____________________ 20-21
F
Firing mechanism: malfunction of___________________ 20
Firing pin, protrusion of__________ 3
Firing pin guide assembly:
inspection of___________________ 10
disassembly of__________________ 10
Firing pin hole____________________ 3
Firing pin retracting pin_________ 10
Firing spring:
free length of__________________ 10
inspection of___________________ 10
replacing_______________________ 20
retainer, inspection of_________ 10
Freezing temperatures, care of gun in________________________________ 23
25
TM 9-1250
INDEX
G
Gaskets, recoil mechanism: Page
inspection of____________________ 14
replacing_______________________21-22
Gland follower, inspection of___ 14
Guide chamber, inspection of___ 10
Guide threads_____________________ 20
H
Housing. (See Closing spring group.)
I
Inspection of guns______________3-14
bore_____________________________ 23
breechblock group_______________3-10
breechblock operating group_____ 13
breech operating mechanism______ 14
breech ring group______________10-13
cam retaining plunger____________ 14
cleaning before___________________ 3
closing spring___________________ 13
cocking lever_____________________ 3
crank assembly___________________ 13
cylinder, recoil_________________ 14
extractors--------------------2-3,10
firing pin________________________ 3
gland follower___________________ 14
guide chamber____________________ 10
gun as unit_______________________ 3
housing group____________________ 13
operating handle_________________ 13
pistons__________________________ 14
plunger: cam retaining__________________ 14
trigfer, spring______________ 10
procedure for_____________________ 2
purpose of------------------------ 2
recoil mechanism_________________ 14
retainer pin________1___________ 10
sear_____________________________ 10
tools for________________________ 2
trigger------------------------10-13
tube____________________________ 3,13
valve collar_____________________ 14
valve spring_____________________ 14
valve lift, checking_____________ 14
yoke__________________________ 3
K Page
Keys, inspection of_______________ 3
L
Lift, valve________________________ 14
Lubrication________________________ 23
(See also Oiling.)
M
Maintenance and repair of gun__ 19-22 breechblock group________________19-20
breechblock operating group______ 21
breech operating mechanism_______ 21
breech ring group______________20-21
closing spring___________________ 21
cocking lever____________________ 20
definition of__________________ 19
extractors_______________________19, 20
firing mechanism_________________ 20
gun as unit______________________ 19
housing group____________________ 21
pistons__________________________ 22
recoil mechanism_______________21-22
tube__________________;__________ 21
Muzzle velocity, data on____________ 2
O
Oil:
kind to use______________________ 23
leakage of_____________________21-22
Oiling----------------------------- 23
before inspection_________________ 3
Operating handle, inspection of____ 13
latch spring, free height of_____ 13
P
Pistons: inspection of______________________ 14
maintenance and repair of________ 22
Pivots, extractor, length of_______ 21
Plunger:
cam retaining____________________ 14
extractor_______________________ 21
trigger------------------------ 21
Projectiles, weight of______________ 2
R
Recoil:
fast and long____________________ 22
slow and short___________________ 22
26
TM 9-1250
INDEX
Recoil mechanism: Page
disassembly of----------------- 14
inspection of------------------ 14
maintenance and repair of------ 22
parts illustrated (M6)-----16,17,18
types of________________________ 2
Retainer pin, protrusion of------ 10
Retracting spring, replacing----- 20
T
Page
Tools for inspection_______________ 2
Trigger, inspection of___________ 10
plunger spring__________________ 10
Tube:
data on__________________________ 2
inspection of______________:----3,13
maintenance and repair of_______ 21
S
Sear, inspection of------------------ 10
retaining pin---------------------- 10
spring:
inspection of------------------- 10
replacing----------------------- 20
Sleigh (M6) illustrated_______________ 5
Springs, free length of:
closing---------------------------- 10
firing____________________________ 10
operating handle latch------------- 13
recoil-------------------------— 14
valve______________________________ 14
[A. G. 062.11 (12-5-41) PC-C]
W
Weak ejection------------------------ 19
• V
Valve collar, thickness of___________ 14
Valve lift___________________________ 14
Valve spring, inspection of--------— 14
Y
Yoke, inspection of---------------- 3
By order of the Secretary of War :
G. C. MARSHALL,
Chief of Staff. Official :
J. A. ULIO,
Major General,
The Adjutant General.
Distribution : D17 (2) IBn 9(2) ; IC 9(4).
(For explanation of symbols see FM 21-6.)
U. S. GOVERNMENT PRINTING OFFICE: 1942
27
ntsu