Identification of NASM81177 & NASM8975 Blind Bolts
MB Blind Bolts carry the following identification head markings.

The special "H" as manufacturer's identification symbol.
Material code letters:
  • Alloy Steel fasteners: =no code letter
  • CRES fasteners: = letter "C"
Grip identification number:
grip range is nominal ±.031"
Example: -04 grip range is .219" to .282"
Illustration of head markings on MS21140U0604

 Grip Thickness Measurements using Huck Grip Gage


Inspection of installed MS Blind Bolts
The position of the spindle break and the lock collar position provide important information about the quality of the installation. Spindle and collar flushness are shown in the table below

Nominal
Diameter

MS90353/90354

MS21140/21141

Pin Position
"A"

Collar Position
"B"

Pin Position
"A"

Collar Position
"B"
-05
 +.020/-.000
 ±.017
 ±.010
 +.000/-.017
-06
 +.024/-.000
 ±.022
 ±.010
 +.000/-.022
-08
 +.030/-.000
 ±.029
 ±.015
 +.000/-.029

-10

+.038/-.000

±.037

+.020/-.015

+.000/-.037
-12
 +.046/-.000
 ±.045
 +.025/-.020
 +.000/-.045

-14

+.054/-.000

±.050

N/A

N/A
-16
 +.062/-.000
 ±.056
 N/A
 N/A