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SR-250L0025

Imperial Structural Locking Inserts

Locking Type / A286 / Structural

Installed using the Crownserts Hand-Installation Tool:  CSTL420

SR-250L0025 repairs/reinforces 1/4-20 UNC imperial threads in Al/Mg or other non-ferrous materials; A286 alloy. Tap hole .281 9/32; install with CSTL420. This is an old Anemo part. Please use CSL420A286.

We can offer you the part SR-250L0025 with Certificate of Quality, Certificate of Conformity and Certificate of Origin on request.

Thread & Dimensions

A internal thread (Class 3B) 1/4-20 UNC
B external thread (Class 3A) 5/16-24 UNF
Ø max minor special .2785
Ø C (+.008/-.002) .252
D (+.015/-.000) .095
E .210
G (±.010) .380
J (±1) 24
Through-hole preparation Min. full THD depth .519; Min. full depth .415
Blind-hole preparation Min. full THD depth .519; Min. full depth .415
SR-250L0025 schematic

Material & Finish

Material A286 per AMS5731 or AMS 5734
Finish PASSIVATED per AMS 2700 & SFL coated per SAE AS5272, Type 1
Temperature range -400°/+650°F
Heat treat RC 32-40
Magnetic NO

Tooling & Preparation

Hand-Installation tool part number CSTL420
Step drill part number CSD0281
Tap through tool part number TTI0312
Blind tap tool part number TBI0312
Removal tool part number CSRT420