MIL-DTL-18240F
Table IX Variables sampling for self-locking screw torque 1/ 2/.
LOT SIZE
SAMPLE
SAMPLE
TOTAL
FIRST
FIRST
COMBINED
SAMPLE
NUMBER
SIZE
SAMPLE
SAMPLES KT
KA
KR
UNDER
FIRST
4
4
2.42
1.35
1.72
151
SECOND
8
12
151 THRU
FIRST
5
5
2.21
.89
1.74
300
SECOND
10
15
301 THRU
FIRST
6
6
2.22
.94
1.70
500
SECOND
12
18
501 THRU
FIRST
7
7
2.32
1.10
1.78
1300
SECOND
14
21
1301
2.48
.99
1.81
FIRST
8
8
THRU
SECOND
16
24
3200
OVER
FIRST
10
10
2.34
1.31
1.80
3200
SECOND
20
30
1/
Evaluate each sample for on prevailing torque on the first cycle as follows:
First sample: Accept if X MAX1 + K ASMAX1 ≤ M . Reject if X MAX1 + K RS MAX1 > M .
Take second sample if lot is not accepted or rejected.
Second Sample: Accept if X MAXT + K TS MAXT ≤ M . Reject if
X MAXT + K TSMAXT > M .
2/
Evaluate each sample for off prevailing torque on the fifth cycle as follows:
First sample: Accept if X MIN1 - K AS MIN1 ≥ L . Reject if X MIN1 - K RSMIN1 < L .
Take second sample if lot is not accepted or rejected.
Second Sample: Accept if X MINT - K TSMINT ≥ L . Reject if X MINT - K TSMINT < L .
Definition of terms:
M
=
Maximum on prevailing torque specification limit per table II
L
=
Minimum off prevailing torque specification limit per table II
X MAX1
=
Individual on prevailing torque values on the 1st cycle
=
Average of X MAX1 values
X MAX1
=
Individual off prevailing torque values on the 5th cycle
X MIN1
x
= Average of X MIN1 values
MIN1
21
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