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Unit of Measure

Insert Type

 N/A Blind

Series

 N/A RJ1200

Material Type

 N/A 4130 Steel

Material Specification

 N/A AMS-S-6758, COND F

Heat Treat

 N/A 125 KSI UTS min

Finish

 N/A Cadmium Plate per AMS-QQ-P-416, Type II, Class 3

Lockring Rosan Part Number

 N/A RLRR28SA8

Lockring Military Part Number

 N/A MS51990-106P

Internal Thread Lock

 N/A No
A - Internal Thread, Class 3B1 N/A 0.2500-28 UNJF

B - External Thread

 N/A 0.3750-16

B - External Thread - Pitch Diameter

 N/A 0.3347-0.3372 in

B - External Thread - Minor Diameter

 N/A 0.2906-0.3011 in

C - Length ±.015

 N/A 0.620 in

D ±.015

 N/A 0.450 in

E - Min. Full Thread Depth

 N/A 0.380 in
Aluminum Step Drill Part Number2 N/A RCDC28-312S
Magnesium Step Drill Part Number3 N/A RCADC28-312S
Basic Tap Size4 N/A 0.3750-16 UNC

Wrench Part Number

 N/A R1106W

Lockring Drive Tool Part Number

 N/A R206D
Removal Drill Size5 N/A 5/16

N/A

  • The external thread has a special pitch diameter and minor diameter which installs into an AS8879 Class 3B, MIL-S-7742 Class 3B, or National Class 3 tapped hole.
  • Mating lockring is not included with insert, it must be ordered separately.
  • Unless otherwise specified dimensions are in inches & ASME Y14.5M.
  • 1 AS8879 Internal Thread
  • 2 Step drills are designed for thru hole drilling. When used to drill a blind hole, it may be necessary to grind the drill to suit the depth required.
  • 3 Step drills are designed for thru hole drilling. When used to drill a blind hole, it may be necessary to grind the drill to suit the depth required.
  • 4 Taps are not supplied by Howmet.
  • 5 Removal drills are not supplied by Howmet.