PS Magazine - SEPTEMBER 1972
PS, The Preventative Maintenance Monthly
1972 SERIES, ISSUE 238
SEPTEMBER 1972
FOR MECHANIcS
1
chanic like a housewife?
\I
-
Why is an Army gRound vehicLe me-
\ ±²
Ans: They both need to know about
th±eads.
This is often pretty easy because tHe
UNF
actualLy looks fine anD the
UNC
reaLLy looks coarse²
But sometimes it's h³rder to teLL 'em
t
The
2
KInds of threa´s the mecHanic apartµ ¶iKe, maybe you'Ve got a stud with
unc-±²ifIed AmerI³a² Sta²daRD ´oarse
uµ ¶·¸ ²I¹IeD Ameri³a² STa²daRD ºi²e
UNC
thReads on one end and
UNF
on ·he
ot¸er, and you haVe to ma·e the coNec·
end with the threads in the hoLe¹
ºn this case it pays to Know a LittLe
More about ·he diffeRences
between
UNC
and
UN»
t¸Reads so you Can figUre
w»a· size t»Reads the hoLe is t¸Readed
forµ
6¼
UNC
thread¼QuicKeR to assembLe½ bet¾
·er Fr use wit¸ aLL ·ypes of cast iron and
¿
steeL, aLuminum, copper, pLas·ic, e·cµÀ use´
to secuRe componen·s ·o a major item,
_
such as oiL pan Áo cyLindeR bLocK, gRiLL
±
dooRs BoLts wiLL usuaLLy bReaK befoRe the
UNC
end is sLightLy oVeRsiZed
so it wiLLÃoR shouLd¼hoLd in the cas·ing
against the ·Urning foRce inVoLVed in ReÄ
moVing t¸e nUt fRom ·¸e
UNF
endµ)
Say you're no· suRe w¸e·heR a boLt is
UNC
oR
UNF.
Jus· coun· the numbeR of
·hReads in an inc¸ and checK it ou· on
this chaRtÅ
BOl½
size
(²n³he´)
1/4
5¾¿À
3/8
7/¿À
1/Á
9/¿À
5/8
3Â4
Ã/8
¿
ÄÅÄ/4
1Æ1/Á
ÇÈMbEÉ OÊ
Threadµ
Per ²n³h
ËÌÍ
ËÌÎ
Á0
Á8
¿8
Á4
1À
Á4
¿4
Á0
13
Á0
¿Á
18
¿¿
18
1Ï
1À
9
¿4
8
¿4
7
¿Á
À
¿Á
doubt, see w¸a· Æype ¸aRdÄ
waRe yoUR paR·s manUaL caLLs forµ Ot»eR
,._
goo´ pLaces ·o checK foR t»e RiG¸t info on
6Ð
•
±
Ñ
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