Skip to main content

CSL428A286

Imperial Structural Locking Crownserts

CSL Series / Locking Type / A286 / Structural

Installed using the Crownserts Hand-Installation Tool:  CSTL428

CSL428A286 is an imperial structural locking crownsert in A286 high-temperature alloy, designed to strengthen 1/4-28 UNF threads in lightweight parent materials. It uses 5/16-24 UNF external threads and CSTL428 installation tooling.

Crownserts can offer you the part CSL428A286 with Certificate of Quality, Certificate of Conformity and Certificate of Origin on request.

Thread & Dimensions

A internal thread (Class 3B) 1/4-28 UNF
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
CSL428A286 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 CSTL428
Step drill part number CSD0281
Tap through tool part number TTI0312
Blind tap tool part number TBI0312
Removal tool part number CSRT428

Crownserts is offering part CSL428A286 as factory new.