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Unit of Measure

Insert Type

N/A Standard

Series

N/A RJ100

Material

N/A 4340 Steel (Alternate 4140 Steel)

Finish

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

Material Specification

N/A AMS-S-5000 or AMS-S-5625

Military Part Number

N/A MS51991-105

Lockring Part Number

N/A RLRR24SA7

Lockring Military Part Number

N/A MS51990-105P

Internal Thread Lock

N/A Yes

A - Internal Thread, Class 3B

N/A 0.1900-24 UNJC

B - External Thread

N/A 0.3125-18

B - External Thread - Pitch Diameter

N/A 0.2769-0.2789 in

B - External Thread - Minor Diameter

N/A 0.2373-0.2468 in

C ± .015

N/A 0.440 in

D ± .015

N/A 0.290 in

Heat Treat

N/A 160-180 KSI UTS

E ± .015

N/A 0.150 in

F - Diameter

N/A 0.248 in

G - Diameter

N/A 0.237 in

H - Diameter

N/A 0.198-0.208 in

J - Number of Teeth

N/A 17.000

K +2º -1º

N/A 86.000 º

L - Diameter +.007 -.002

N/A 0.284 in

M - Diameter +.005 -.004

N/A 0.255 in

N ± .015

N/A 0.090 in
Aluminum Step Drill Part Number1 N/A RCDC24-257
Magnesium Step Drill Part Number2 N/A RCDAC24-257

Basic Tap Size

N/A 0.3125-18UNC

Wrench Part Number

N/A R1105W

Locking Drive Tool

N/A R105D
Removal Drill Size3 N/A F

N/A

  • The external thread has a special pitch diameter and minor diameter which installs into a AS8879 class 3B, MIL-S-7742 class 3B, or National class 3 tapped hole.
  • Inserts are installed and removed in accordance with MS51995.
  • Insert lengths shown are based on installation in 2024-T4 Aluminum and in such materials will accommodate tension loads up to the strength of a mating bolt heat treated to 145,000 PSI UTS. If this design criteria is required in parent materials of lower mechanical properties, longer insert lengths should be specified. Mating bolts should have a thread engagement of 1.5 diameters or if insert has a thread lock, the bolt should extend through the insert 2 pitches including chamfer.
  • Mating lockring is not included with insert. It must be ordered separately.

  • 1 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.
  • 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 Removal Drills are not supplied by Howmet.