PS Magazine September - October 1952 Number 9 [9 ed.]

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Citation preview

PS Magazine has had quizzical letters from lots of new readers as to who we are and how we do what we do. To all such, attention is respectfully invited to page 2 of issue Number One. It tells all, and in the proverbial nutshell. Sweets for the sweet, so to speak. Except one thing that seems to bother you e very so often and makes PS quite sad. You poke your loaded pencil in our general direction and you say to us, " . .. and just how official is PS????" Well si r, PS fires right back- PS is official as they come. With a capital "Oh ." It's not what you'd call a directive, but everything it says to you is as checked and double-checked as technical facts should be. Everything in PS is approved by the technical authorities who approve those same facts for the directives that come later-and publication in PS constitutes

official approval. Beside s, friend, the men who know the IG best can tell you that nobody ever got a gig for ado pting PS information to local conditions. If it's good facts and it works to practical advantage, then by all means let your common sense be your guide and more powe r to you .

S_EPTEMBER-OCTOBER 1952

IN THIS ISS U E TANK.AUTOMOTIVE M46 Turret Drift M38 ·'tems Track Jack Modification Icy Driving Up-dating the M135 Reversed Polarity

PS Magazine has had quizzical letters from lots of new readers as to who we are and how we do what we do. To all such, attention is respectfully invited to page 2 of issue Number One. It tells all, and in the proverbial nutshell. Sweets for the sweet, so to speak. Except one thing that seems to bother you every so often and makes PS quite sad. You poke your loaded pencil in our general direction and you say to us, " ... and just how official is PS????" Well sir, PS fires right back-PS is official as they come. With a capitol "Oh." It's not what .you'd call a directive, but everything it says to you is as checked and double-checked as technical facts should be. Everything in PS is approved by the technical authorities who approve those some facts for the directives that come later- and publication in PS constitutes official approval. Besides, friend, the men who know the IG best can tell you that nobody ever got a gig for adopting PS information to local conditions. If it's good facts and it works to practical advantage, then by all means let your common sense be your guide and more power to you.

365

366 369

370 376 377

ARMAMENT & AMMUNITION High-Angle Cant

Preventive Maintenance ... A Command Responsibility

3B6

FIRE CONTROL High-Angle Cant

386

ARMY AIRCRAFT

"Preventive Maintenance is not a modern invention. Commanders have always been charged with insuring that all elements of their commands, human and material, be ready and able to accomplish an assigned task. This can be done in only one way-by everlasting interest of every member of the chain of command-in short, by recognizing that maintenance is not the job of the technician, important as he may be, but the job of the commander. PM is a command responsibility."

Windy's Windstorms

400

SUPPLY The New UER

402

DEPARTMENTS Editorial PM-Command Responsibility Combat Maintenance Connie Rodd Cartoon Continuity Joe-Dope Limerick Half-Mast Windy Windsock Contributions Connie Rodd's Briefs

2C 361 362 372 378 384 394 398 405 3C

PS MAGAZINE, the Preventive Maintenance monthly, welcomes your ideas and questions. Write to: Editor, PS Magazine, Aberdeen Proving Ground, Maryland.

Maior General I. D. White Commanding 10th Corps

The printing of I'S Moga~ine, the PREVENTIVE MAINTENANCE MONTlllY, is approved by th e Director, Bureau of the ludget (14 Feb 1952), and is distributed as follows: ACTIVE UMY: Ted. SV( (~) , mept 9 (250); Admin & Teth 5v( Bd (10); AfF (10); OS Maj Comel (100); Base Cornd (5); MOW (5); A (lOO); CNQ (5); Div (50), except 17 (IOO),Tng Div (SO); Brig (5); Regt (IO); 5bn (10); Bn (5); (0 (12), except 9 (20), 17 (20). 55 (20); FT (5); Sth (25), except 9 (SO) ; USMA (25); ~Ms&T IS), empt 9 (25), Dap (10); lIosp (lS); ffiE (3); 050 (2); Ar1 (25); Dspln Ik (25); Ret 5to (3); Div Engr (5); Rct Dist (3); Mil Dist (100); ~RGR (5), exclpt 9 (25); RTC (100). MG. SpKial. OR(: Nonl. F1lr explanation of distribution formulo I" SR 310·90·1.

361

5_EPTEMBER-OCTOBER 1952

IN THIS ISS U E TANK-AUTOMOTIVE M46 Turret Drift M38 Items Track Jack Modification

365

366 369

Icy Driving Up-dating the M 135

370 376

Reversed Polarity

377

ARMAMENT & AMMUNITION High-Angle Cant

Preventive Maintenance ••• A Cammand Responsibility

386

FIRE CONTROL High-Angle Cant

386

ARMY AIRCRAn

" Preventive Maintenance is not a modern invention. Commanders hove always been charged with insuring that all elements of their commands, human and materia l, be ready and able to accomplish on assigned task. This can be done in only one way-by everlasting interest of every member of the chain of command-in short, by recognizing that maintenance is not the job of the technician, important as he may be, but the job of the commander. PM is a command responsibility,lI

Windy's Windstorms

400

SUPPLY The New UER

402

DEPARTMENTS Editorial PM-Command Rttsponsibility Combat Maintenance Connie Rodd Cartoon Continuity Joe-Dope Limerick

2C ' 361 362 372 378 384

Half-Mast

394

Windy Windsock Contributions Connie Rodd's Briefs

398 405 3C

PS MAGAZINE, the Preve ntive Maintenance monthly, welcomes your ideas and questions. Write to: Editor, PS Magazine, Aberdeen Proving Ground,

Major General I. D. White Commanding 1 Dth Corps

Maryland.

The prJatill9 of PS Magazine, th e 'REfEMTlYE MAINTENANCE MONTHLY, is approved by the Dlre(\or, Bureau of the Budg.t P4 Feb 19S21, lind is distributed as follo'/l'5: AalYE ARMY: Tuh 5v( exupl , (250); Admin & THh Sn Bd (10); AFF (10); OS Maj Comd (100); ~H (omd (5,; MOW (5); A (100); (HQ (5); Diy (SO), U(lpt 17 (100); Tng Diy (50); Brig (5); Regl (10); Sbn (10); Bn (5); Co (121. mepl 9 (20),17 (20), 55 (20); fT (5); xh (25), uupl9 (SO); USMA (25); PMS&T (5), except 9 (25); Oep (10); Hosp (15); POE (3); 050 (2); Als (25); Dspln lie (25); Rei Sia (3); Div Engr (5); Rei Di51 (3); Mil Disl (100); PIG. (5), except 9 (25); RTC POOl. MG. speda!.

m,

OK: Hone. for explonotion of distribution formula

5ee

sR 310.90-1.

361

FAR EAST ENEMY NO.2-MUD AND ICE

Dear Editor, So far as artillery is concerned, we've found only one way to combat mud and ice, Enemy No. 2 in the Far East. With grease. Elbow grease and lubrication. Much of the time traveling in Korea means sloshing through mud or water-detouring around blown-out bridges. Most of the bridges have been blown out. Doesn't take long for the mud and water to freeze. When you try to set up your artillery you're up against all kinds of difficulties. Chances are the slots in the trail spades have gotten clogged with mud and ice. Which means that they have to be cleaned and lu-

bricated before the spades can be put in place. t;~~~~~~~~t'~~ Then there's the firing jack. Ease of opera- • tion is important. When the plunger freezes it slows you down five or ten minutes in getting your gun into firing position. You've got to keep your firing jack free of dirt and ice, and well lubricated. We've found that on the lOS-Howitzer the equalizing support pintle must be lubricated immediately after going thru water, and given a thorough grease job at the same time. This procedure applies also to equalizing support locks. Some outfits let their ball and socket on the rear of the trails get wet, causing them to rust. They should have grease on them just about every move that's made. Out in the field it's hard to hang onto gun covers, so most of the guns are out in the weather unprotected during the rainy season.

FAR EAST ENEMY NO.2-MUD AND ICE

Dear Editor, So far as artillery is concerned, we've found only one way to combat mud and ice, Enemy No.2 in the Far East. With grease. Elbow grease and lubrication. Much of the time traveling in Korea means sloshing through mud or water-detouring around blown-out bridges. Most of the bridges have been blown out. Doesn't take long for the mud and water to freeze. When you try to set up your artillery you're up against all kinds of difficulties. Chances are the slots in the trail spades have gotten clogged with mud and ice. Which means that they have to be cleaned and lubricated before the spades can be put in place. Then there's the firing jack. Ease of operation is important. When the plunger freezes it slows you down five or ten minutes in getting your gun into firing position. You've got to keep your firing jack free of dirt and ice, and well lubricated. We've found that on the lOS-Howitzer the equalizing support pintle must be lubricated immediately after going thru water, and given a thorough grease job at the same time. This procedure applies also to equalizing support locks. Some outfits let their ball and socket on the rear of the trails get wet, causing them to rust. They should have grease on them just about every move that's made. Out in the field it's hard to hang onto gun covers, so most of the guns are out in the weather unprotected during the rainy season.

The cradle slides rust and won't give the proper recoil. The whole gun should be lubricated two or three times a week. Sgt Ray J. Godsey Korea TRUTH IS STRANGER THAN FICTION -CHANGE YOUR FLATS

........."""'..... Dear Editor, Hate to tell this one on myself but in the interest of some other fellow who may find himself in such a spot-here goes: I'm a driver for a TC outfit in Korea and was pushing a load of ammo to a forward area, grousing about the terrain I had to cover and the equipment I had to do it with, when one of my tires (an inside dual) blew out. I wasn't too far from home so I decided to keep going. When I pulled in to the motor pool the place was pretty well deserted. It was late and I was beat so I hit the sack. I didn't think anybody'd notice the flat, it being an inside tire, and I could take care of it in the morning. I sure wasn't expecting the fireworks that woke me up a few minutes later. Seems that when I parked that truck on the lot the flat tire was smouldering inside the casing and it soon got the good tire to smouldering. Then the good tire blew out and the air from it fanned the smoulder into flames. Soon the wooden body of the trailer was aflame- and then the ammo-and then ... Cpl L. W. Budd Korea

The cradle slides rust and won't give the proper recoil. The whole gun should be lubricated two or three times a week. Sst Ray J. Godsey Korea TRUTH 15 STRANGER THAN FICTION -CHANGE YOUR FLATS

Dear Editor, Hate to tell this one on myself but in the interest of some other fellow who may find himself in such a spot- here goes: I'm a driver for a TC outfit in Korea and was pushing a load of ammo to a forward area, grousing about the terrain I had to cover and the equipment I had to do it with, when one of my tires (an inside dual) blew out. I wasn't too far from home so I decided to keep going. When I pulled in to the motor pool the place was pretty well deserted. It was late and I was beat so I hit the sack. I didn't think anybody'd notice the flat, it being an inside tire, and I could take care of it in the morning. I sure wasn't expecting the fireworks that woke me up a few minutes later. Seems that when I parked that truck on the lot the flat tire was smouldering inside the casing and it soon got the good tire to smouldering. Then the good tire blew out and the air from it fanned the smoulder into flames. Soon the

Cpl L. W. Budd Korea

363

GIVE IT TO 'EM STRAIGHT

Dear Editor, I'm writing a message I hope you'll publish to all drivers and mechanics. Let's bear down on those guys. They aren't driving taxis or commercial trucks for a civilian concern. They are driving combat vehicles (in this theater) and 1st echelon or Driver's maintenance is the life of those vehicles. Instead of getting in a truck, turning on the switch, jerking the transmission in 1st gear and burning up the clutch and tires-let's look them over, feel of a few of the bolts and nuts for looseness, pet those buggies as you would your baby. Those vehicles can and will save your life in combat if you do your part. Your part as a driver is also taking care of, them- not just cowboying the vehicle around. In 14 months of combat in the E:T.O. the last time around-'Of 26 vehicles in Hq Btry 928 FA Bn there was orie 1/4-ton out of commission for one day. A brake job. And credit goes to 26 drivers and their section chief$. They did the job there in combat, we can do it now-20 or 30 minutes a day. Keep them tight, keep them lubricated and clean, and the vehicle will do the job for you. TS9t E. J. Smith APO 929, San Franci$co HOT TIP ON WP SHELLS Dear Editor, One thing I learned in Korea which is worth passing on is the importance of keeping your WP (white phosphorus) shells nose-up in hot weather. If you don't, the phosphorus will melt and run down to the low side of the casing, off-setting the shells' cj3nter of gravity. When fired they'll come out of the gun like a cat with fits, and hit anywhere from here to barn.

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........

1/16"' thick, 5/32"' wide and 2-1/2" long. Bend and shape it with a pair of round-nosed pliers (Fig. 2). To give the home-made spring the proper elasticity, heat it to a cherry-red color (1400-16000 F) and drop it in oil. This'll make it hard. To temper the spring: attach it to a wire and dip it back into ankers blame sudden anti-recoil the oil, pull it out, and ignite the failures on the spring breaking in oil on the spring with a torch. As the traversing mechanism's "No- soon as the oil burns off, immerse Back" unit (Fig. 1). it in the oil again, .immediately To replace this spring, have pull it out, and ignite the oil. Refield maintenance remove the unit peat this dipping and burning proand take out its innards. Page 475, cedure six times. When all's done, ORD 9 SNL G-244, April 1951, you'll have a spring that'll keep gives an idea how the assembly your turret from drifting when comes "apart- the part that's break- parked on a slope until the requiing is labeled "AA". The spring sitioned spring comes through. could look like "AA" in the SNL, or '( more likely) it looks like the later-type spring in Fig. 2. To depress new spring into the unit, get a piece of 114" steel about 6" long and ,1-3/4" wide and press spring into place by gripping steel in your fist and using a flat end. Avoid pliers or screwdriver because they'll damage the spring. The spring (G244-8329017) isn't in stock- but it can be requisitioned on the basis of MWO G244W28, soon to come. In the meanwhile, to keep from sitting around in a turret-drifting tank waiting for a spring to come through - your best bet is to have field maintenance make one. SHAPE OF SPiING USED Get a small piece of"spring IN THE NO-UC! ASSEMILY metal, preheat, cut and file it till it's

M46Al lilies

T

~

365

The more ottention she gels, The less trouble she gives.

your M38 feelin' great? This idea can also be used to M38 Cuno type oil filters give keep fuel pump sediment-cups in little trouble but they need some trim if they go astray. attention to keep them working right. Besides the usual cleaning, t /~;~_C~j*1 after two or three thousand miles There's been some complaint of of operation they sometimes start M38 throttle wires breaking off leaking and require extra care. where they're stackeq inside the The reason for this leak may be ratchet tube of the hand throttle. that in manufacture the cup flange This tube should be lubricated reg(the sealing surface) is left unma- ularly but it's often forgotten. Needing a little oil, the ratchet chi ned and rough. As a remedy. smooth down the flange on a piece tube gets stuck. Next thing you of abrasive cloth resting on a flat know, you pull extra hard-the hansurface. If you can replace the gas- dle comes out with a jerk, and the ket (Stock No. G740-737S0S9) wire is broken. This can be uncomwith a new one, swell. Otherwise fortable if it happens while fordtake the old gasket Qut, tUrn it ing. If preferred, graphite can be over, and reassemble. A good gas- used in place of oil. In any eventket means a lot if you want a leak- it's a part you should be able to proof filter (Fig. I ). move, so why not keep it movable?

~------~~-------

o

Fig. l-Not only do you need a good gas\r.et for a leak-proof (uno filter, you also need a smooth sealing-surface on the cup flange. And remember to tighten the bolts evenly, all the way around, when you reassemble the filter-uneven tightening makes for leaks, as you know. 366

Removing and replacing the front or rear differential cover a few times can give it a permanent buckle. The stuff the cover's made of isn't tough enough to keep its shape when there's been uneven pressure against it. And that means GO leaks down-under. ! Using a thin cork gasket and a soft sealer, like aviation Permatex #3, can help at this point. Or, try cutting a ring from some mild steel to fit the circumference of the cover, drill holes for the cap screws, and weld it to the outside of the cover. Add a softer and thicker gasket to this and you're set. But most important, it's best if you make the cover tight without buckling. To get an even tightness on the housing, put all the screws on finger-tight first. Then working clockwise, give each screw a quarter tUrn at a time until they all have a prop·e r and equal snugness. Incidentally, if you're raising an M38 with a roll-away floor jack, be careful. A light smack from the jack can crack the differential cover.

The bottom of your clutch pedal may be nibbling at your fuel line every time your left foot lams down on top of it. In fact on some vehicles the brass tee-fitting at the fuel-line shut-off-valve has been cracked by the pedal being too close and slamming it too hard. If the situation

there looks threatening, you can move the line safely away from the bottom pedal clevis, according to a coupl'a users who've written PS about the change. Their idea is to put a hole in the front body-mounting bracket directly in line with the fuel line and run it through this hole. (Fig. 2 and Fig. 3) . That way, the bracket acts as a bundling-board and keeps the line and pedal clevis away from each other's nudging.

Fig. 2 If fuel line in this position gets banged by dutch-pedal devis, grommet the line and run it thru the mounting bracket.

Fig. 3-After you've drilled a hole in the bracket and run the line thru, dip the line on the other side using the same bolt hole.

367

weaker and returned to normal after the vacuum line was disconnected. That figures, since air When an M38 started to miss becomes a better conductor of elecand backfire, Ed Hinsdale, OCT 1't tricity as pressure is reduced. The Camp Stewart, Georgia, found partial vacuum accidentally set-up that disconnecting the tube be- in the distributor made an easy air tween the vacuum booster and path for ignition current to reach windshield wiper made the little ground inside the distributor case, giant purr like a kitten. Recon- short circuiting the spark plugs. necting the hose and tracing the While it won't happen in all vent line through the distributor vehicles, a job with a booster (like and into the carburetor-air-intake that on the M38) creates enough pipe, he discovered that the elbow, of a vacuum to make the difference. terminating the vent line in the And from the positive side, this is carburetor-air-intake pipe, got a good way to test the sealing, ventplugged with brass somewhere ing, and waterproofing of the disalong the production line. By clear- tributor. When everything else is ing the brass-clogged passage he fit and snug, and all the vent conmade everything OK. nections tight, disconnect the top While scratching around, MSgt vent-line, cap it with your finger, Hill noticed that the spark had been and the engine should start to miss.

TRAILER-CABLE SOCKET-COVER · FIXES Two ways to keep trailer_cable socket-covers from scratching or breaking reflectors

An unlocked socket-cover does the damage. If you grind 3/16" from the lock's upper corner, it will be free for good locking action.

Or if the lock's broken, turn the M38's receptacle so it opens from the side,and plug the socket in sideways, too---reflector clear.

368

TRACK-JACK MODIFICATION track-pins. Then weld this wedgeDear Editor, If anyofyourreaders are plagued shape lug 'onto the overall surface by the -soft-headed end-connector- of the track's puller-pin mount. puller pin snapping off their M 4, Mount the lug so its pulling surface M26, M46, M46Al and M47 track- is a perfect 90' from the jack's body, jacks (oh, my aching knuckles), as shown below. they'll want to hear how we went When ';sing this modified jackabout reclassifying our jacks from pin, reverse it from the usual blasted to blessed. We modified . position, insert the lug into the endthe jack's pin (41-F-299S-200) so conneCtor's wedge-recess and pull it would stand up and do the rugged away- it won't slip or break and the job of pulling off the end-connec- connector comes off neat 'n easy. tors from most center-guide chev- Requisitioning new fixtures beron-type tracks. cause of a broken or buggered pulOUf fix: cut off the _puller-pin, ler-pin is a thing of the past in our and in its place weld a wedge- outfit. SFC A. H. Steele shaped lug that's the general size APG, Maryland and shape of a drive-sprocket tooth. (Ed Note-Sounds OK, but get a The lug (cut from a piece of armor plate) is 2" long, 1-3/8" wide, and good weld on that lug. Your fix can 1" high. Cut and shape both ends so also be used on the M24 track-jacks the lug will fit into the connector's (Fixture 41-F-2997-86) by makwedge-bolt recess and clear the ing the lug a little smaller,)

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The head behind the feet Keeps a truck safe on ice.

r center the ang le-of-site level· bubble by turning the angle-of-site micrometer

knob. Set the panoramic telescope azimuth sca les to 1600 mils (pointing 90 0 away from the tube). Hang a plumb line and aline it with the vertica l hair in the telescope reticle. · Sight through the telescope and rotate the telescope elevation micrometer knob through the extent of travel. The vertical hair should , remain in coincidence with the plumb line. If rhe vertical hair and the plumb line do not remain in coincidence, the telescope socket and the mount are not correctly alined and must be adjusted or repaired. (Incidentally, all major adjustments to the Fire Control equipment should be made by Ordnance.) When these checks a.nd adjustmems are run through, the bore-sight vertical line should track the plumb line and (he sight should stay on your aiming point. If the sight doesn't stay on, or return to the aiming point, there's residual cant in your artillery piece. When an artillery piece of this type is found and immediate anemion cannot be given to locating the cant, temporary adjustments can be applied co the gun by pre.determining the cant at various elevations and making corrections for it before firing.

!be ~ methocI ~ _~~~ in all y... boo!