PS Magazine Issue 050 1956 Series [50 ed.]

Citation preview

Jllteh1tJiel'4"'" Cltri tmllH and und .. r Ihc h'ce were toys di_mbleel and pari. _('allc" cd W8M jamm...d "ith a hon.n-danglillg lank withoul Irad•• and a r.. r ... ·lirt was lamc.

lI·hour al'l'r""dli,,~. II ... I..... '" "('ad)' 10 ral'l ~~l'.tii.. r"... r'H"k~'r ,..t·r~t·ant l!ul Ih(" c'rt'" on th e ...., ..._,.......... t1"'l'arl. li'l ""d ""111",,1,'!~ '1'1,,' nnl.·r

rt"IUrnffl 10

llu--

IIU"", ...

un the fI

tOn Itt" "la.H..'cd al the h 'ee, nd .101'1,...1 It) Ihe d"OI' wilh aJla.!!l;I~~Ip,~;P;:9'JJd~N l'h.. n Ih.·,. Ilt'ard hi", exclaim ,

"j$lerrp

qEbri~tma~

to all--

And Luhe Them Toys Just Right"

The help gou need ;$-

AS NEAR AS YOIJR TELEPHONE Here's the way to get better maintenance on your unit's equipment: When you have some question or problem you can't answer or solve yourself, get help from Ordnance, Engineers, QM, Chemical or your other technical services -right there in your Division or on your Post. It's easy-iust pick up the phone and call the technical people concerned with the equipment you want help on . They 'll also help you clarify TM's, TB's, 5S's and AR 's. So-ring 'em up. They 're there to help you keep your equipment better maintained. A phone call ~-"",_... _ today may prevent a deadline "fomorrow.

The help gou need ;$-

AS NEAR AS YOIJR TELEPHONE 1956Se ri"

Here 's the way to get better maintenance on your unit 's equipment: When you have some question or problem you can'f answer or solve yourself, get help from Ordnance, Engineers, QM, Chemical or your other technical services -right there in your Division or on your Post. It's easy-iust pick up the phone and call the technical people concerned with the equipment you want help on. They 'll also help you clarify TM 's, TB's, S8 's and AR's . So-ring 'em up. They're there to help you keep your equipment better maintained. A ph o ne call I...."::::.,,......~ today may prevent a deadline tomorrow.

Publi$~ed

by tbe Department of the Army for ttle information of

organizational maintenance and supply personnel. f)istribution is made through normal publication channels. Wi~hi n limitations, of availability, older issues may be , obtcHned' direct from Preventive Maintenance,Agency, Raritan Arsenal l Metuchen, New Jersey.

IN THIS ISSUE ARTICLES Slave Starting Vehicles Battery Care in Cold Weather Low.Voltage Circuit Tester Replacing Light Switches Tank Engine fires Gas Mask Care Strekhing Solvent Supply Sniperscope

2 4 12 26 37 42 46

52

DEPARTMENTS Connie Rodd Small Arms Artillery Nike Notes Half·Most Chemical Ouartermaster Engineer Contributions Conn;e Rodd's Briefs

9 18 20 22 37 42 46

50 62 65

~S wants your ideas and contributions, and Is glad. to answer your questions. Jost write to: sat Half·Mast PS ; Raritan Arsellal Melutllen. New Jersey. Names ,and addresses are kept In confidence.

Published by the Department of the Army for the information of

organilational maintenance and supply personnel. Distribution is made through normal publication. ,channels" Within limitations of availability, older ' Issues may be obtained direct 'trom Preventive Maintenance AgencYf Raritan Arsenal, Metuchen, New Jersey.

IN THIS ISSUE Slave Startill9 Vehicles Battery Care in Cold Weather Tester Replacing Light Switches low~Voltage Circuit

Tank Engine Fires

Gas Mask Care Stretching SOlvent Supply Sniperscope

2 4 12 26 37 42 46 52

DEPARTMENTS Connie Rodd Small Arms Artillery Nike Notes Half-Mast Chemical Quartermaster

9 18 20 22 37 42 46 50 62 65

Engineer Contributions Connie Rodd's Briefs PS wants your id,eas and contributions, and is glad to answe~· your: QuestJons. Just write to~ S1I Half·Mast, PS. Raritan Arsena~ Met:lcbeo. New Jersey, Nam~,s,' and: addresses: are kept ineonHdence. The prfntflll 'of PS Magaline, the PREV£NTlVE MAINTENANCE MOIfTHLY, ii 3J1prllVed by

the Director, BUreao ,I tbe Budget {4 AI,,53), and is dlstribllted u flIlllws: DISTIl· BUTlIJK: ACTIVE AItMY; Gen Statt. DA run t DCSPER t2}; SS.'1lA t1}: Tee S.c, DA

EftJr Scb (10D), OrdStll(25~ USMA(25J; Mcept PMST Ord ROTC Ululs (25); Gn Oepot~(5); SII, «, Gn DepOf$:(5): Deptts (5}, AtlI5};RTt (1nt1); us Army Ttl, Cell (50): Trans Terminal Comd(3); Atmy TetlJlfn.ff3l; OS Sup AlentieS(2); PG(5l;4rsenals (25): &8(25): Cruit Main Sta(3); Div Engr (2); Dist [n,rI20~ NG: Sute AG Special List USAR~ Mil nlst Special I.i$t. For explanati," ., ahbnviatfoas used See' 51 328·50.1.

{

7. Remove coble plug from each tonk. And keep this in mind all along. Once you idle the engine (or engines) and have the master switches OFF, the sooner you can get that cable out and the master switches back on-the better. For at least two very good reasons: (1) It cuts down the chances of somebody gunning the engine while there's np load (batteries) in the drccit- and slaughtering those filaments; (2) It's JUSt no good for an engine [0 run at low idle any longer than necessary-fouls your plugs in a hurry. So ... shake a leg, hey? You'll save a lotta bulbs and bother. This procedure also applies to the light tank family, with one exception-the M42 Self·Propelled Twin 40. It has its master relay between the slave receptacle and the other circuits. So, unless the master switch is ON and the relay closed, you can't get outside currenr [0 the starter. Which means that you have to slave start an M42 with its master relay switch ON. BUI-you'll still want [0 Hip it OFF (and idle the engine) to prevent an arc when y'disconnecr the cable. ALSO NOTE-Some M46 tanks have a 3-position master relay switch. When starting one of those babies, first turn the switch to HGEN" and let it run until the batteries are charged to at least 18Y.z volts. (That's what it takes to hold the relay closed.) Then switch to "BATT."

7. Remove cable plug from each lonk. And keep this in mind all along. Once you idle the engine (or engines) and have the master switches OFF, the sooner you can get that cable our and the master switches back on-the better. For at least two very good reasons: (1) It cuts down the chances of somebody gunning the engine while there's np load (batteries) in the circcit- and slaughtering those filaments; (2) It's JUSt no good for an engine to run at low idle any longer than necessary-fouls your plugs in a hurry. So .. . shake a leg, hey? You'll save a 10tta bulbs and bother. This procedure also applies to the light tank family, with one exception-the M42 Self-Propelled Twin 40. It has its master relay between the slave receptacle and the other circuits. So, unless the master switch is ON and the relay closed, you can't get outside currenrto the starter. Which means that you have to slave start an M42 with its master relay switch ON. But-you'll still want to flip it OFF (and idle the engine) to prevent an arc when y'disconnect the cable. ALSO NOTE-Some M46 tanks have a 3-position master relay switch. starting one of those babies, first turn the switch to "GEN" and let it run until the batteries are charged to at least 18Y2 volts. (That'S what it takes to hold the relay closed.) Then switch to "BATI."

(Or-How to thumb your nose at your batteries behave on frosty days and what you've got to do to keep 'em healthy. First of all, be sure to correct your hydrometer readings for temperature. All standard hydrometer figures were established for a temperature of 80° F. To correct them for different temperatures you add 4 gravity points for each 10 degrees above 80°, and you subtract 4 gravity points for each 10 degrees below 80°, Your Ordnance hydrometer, Oed Stock No. lS-H-124120, has a thermometer and a temperature correction table built right into it, so you won't have any trouble getting the right answer. Let's see how this works with a battery reading 1.220 on a day that's 1 below 0° (Brrrrrrr!!) Ten below is 90 degrees below 80°, so you have to subtrace 36 points (9 times 4). Subtract 36 from 1.220 and you get only 1.184. Not only does this mean that your battery is less than 25 % charged. it also means that it's. getting mighty close to its freezing point. The first thing to do is check your hydrometer reading and be sure that it is at or above 1.250, corrected. If you find that the battery is below 1.250 corrected, charge it up, and also check your generator output, which should be 27 to 29 volts. If your generator's putting out OK, and your battery's corrected hydrometer reading is at least 1.250 you're in pretty good shape. Remember, you've got to watch that battery ~~v~WA~;;:,t,,[ like a hawk all during the cold weather. If . proves that your vehicle's not getting '':-'''''''~;;;;;~~ enough miles between starts to keep the battery up, you'll have to keep batteries and having 'em charged by the shop men. Or maybe you can get your truck rotated around onto some long hauls to keep the battery ~p 4

your batteries behave on frosty days and what you've got co do (0 keep 'em healchy. First of all, be sure to correct your hydrometer readings for temperature. All standard hydrometer figures were established for a temperature of 80° F. To correct them for different temperatures you add 4 gravity points for each 10 degrees above 80°, and you subtract 4 gravity points for each 10 degrees below 80°. Your Ordnance hydrometer, Ord Stock No. 18-H-124120, has a thermometer and a temperature correction table builc right into it, so you won't have any trouble getting the right answer. Let'S see how this works with a battery reading 1.220 on a that's below 0° (Brrrrrrr!!) Ten below is 90 degrees below 80°, so you have CO subtract 36 points (9 times 4). Subtract 36 from 1.220 and you get only 1.184. Not only does this mean that your battery is less than 25% charged, it also means that it's.getting mighty close to its freezing point. The first thing to do is check your hydrometer reading and be sure that it is at or above 1.250, corrected. If you find that the battery is below t .250 corrected, charge it up, and also check your generator output, which should be 27 to 29 volts. If your generator's putting out OK, and your battery's corrected hydrometer reading is at least 1.250 you're in pretty good shape. Remember, you've got to watch that battery like a hawk all during the cold weather. If proves that your vehicle's not getting enough miles between starts to keep the battery up, you'll have to keep batteries and having 'em charged the shop _men. Or maybe you can get your truck rotated around some long hauls to keep the battery up _ _ _Ioc, __ 4

one. ' time you fai l to get your engine started on a real p>ld "'d ay, or if you have to crank a long time and then go on only a short run, 'you're in danger of gening your battery frozen. This is because the chemical reaction in the battery which produces the electric current absorbs some of the