Metric Mismatch; Inch Thread Vs. Metric Thread Fastener Combinations Contributing To Thread Stripping - Mack E7 Service Manual

5-101.bk Page 20 Friday, March 17, 2006 11:05 AM

METRIC MISMATCH

Certain metric/English fastener thread
combinations are incompatible and may
result in mismatch conditions. These
conditions can cause thread stripping and/or
assembly weaknesses which may lead to
service failure, rendering a vehicle
inoperative or unsafe for operation.
Inch Thread vs. Metric Thread
Fastener Combinations
Contributing to Thread Stripping
The following inch/metric screw and nut (or
tapped hole) combinations can be finger started
(at least two full turns), but will strip if fully
assembled.
Inch Screws
4-40
5/16-18
*5/16-24
3/8-16
*3/8-24
7/16-14
*7/16-20
*1/2-20
*5/8-18
*7/8-14
*1-12
*Fine thread
Page 2-20
200 SPECIFICATIONS
5-40
1/4-20
*1/4-28
*5/16-24
7/16-14
7/16-14
7/16-14
1/2-13
*1/2-20
1/2-13
*1/2-20
1/2-13
9/16-12
*9/16-18
*5/18-18
1-8
Metric Nuts
*Fine thread
M3 x 0.5
M8 x 1.25
M8 x 1.25
*M10 x 1.25
*M10 x 1.25
M10 x 1.5
*M10 x 1.0
*M12 x 1.25
M12 x 1.75
*M10 x 1.25
M14 x 2
*M16 x 1.5
M24 x 3
M27 x 3
Inch Nuts Metric Screws
M3 x 0.5
M6 x 1.0
M6 x 1.0
*M8 x 1.0
M10 x 1.5
*M10 x 1.25
*M10 x 1.0
M12 x 1.75
M12 x 1.75
*M12 x 1.5
*M12 x 1.5
*M12 x 1.25
M14 x 2
*M14 x 1.5
*M16 x 1.5
*M24 x 2