Metric Sockets, Wrenches, Hand Twelve Point, High Strength, Thin Wall
AS955
This SAE Aerospace Standard (AS) covers high strength thin wall (commercial) metric sockets, universal metric sockets, metric box wrenches and metric torque adaptors which possess the strength, clearances, and internal wrenching design so configured that, when mated with 12 point fasteners conforming to the requirement of ISO 4095, they shall transmit torque to the fastener without bearing on the outer 5% of the fastener's wrenching points. This standard provides additional requirements beyond ASME B107.100 and B107.5M appropriate for aerospace use.
Inclusion of dimensional data in this document is not intended to imply that all of the products described herein are stock production sizes. Consumers are requested to consult with manufacturers concerning lists of stock production sizes. The dimensional limits of box and combination wrench lengths have been established to provide configuration control for tool storage applications.
Rationale: The SAE AS955 standard was issued in July 2012. It covers thin wall, high strength, twelve point metric hand sockets and wrenches; and was intended as the companion standard for SAE AS954. The metric tools were incorporated into SAE AS954H (2023), eliminating the need for the AS955 standard.
Normally, AS955 would be stabilized. The standard contains errors; however, and thus needs to be cancelled. The socket portion of AS955 incorporated SAE MA5434 Socket Wrenches, Hand (Metric). The problem with this is that the sockets specified in MA5434 were intended for use with hex fasteners, while the scope of AS955 and AS954H are sockets and wrenches for use with high strength twelve point aerospace fasteners. This resulted in AS955 containing socket specifications which did not accommodate the minimum opening depth and minimum bolt clearance diameter required for twelve point fasteners. This was corrected with the incorporation of the data into AS954H.
The scope for SAE MA5434 is as follows. It documents that the standard was intended for use with hexagon fasteners.
“This SAE Aerospace Standard covers high strength commercial sockets and universal sockets which possess the strength, clearances, and internal wrenching design so configured that, when mated with hexagon (6 point) fasteners, they shall transmit torque to the fastener without bearing on the outer 5% of the fastener's wrenching points. This document provides additional requirements beyond ANSI B107.5 appropriate for aerospace use.”
Furthermore, note 5.2 from SAE MA5434 clarifies that this standard is not for use with 12 point fasteners.
“These sockets are intended for use with hexagon (6 point) fasteners. No changes to ANSI B 107.5 requirements for depth of opening at the nut end have been addressed to verify adequate wrench engagement with 12 point nuts with locking collars nor has the diameter of the bolt clearance hole been adjusted to insure adequate clearance. MA1547 [sic] posesses the necessary clearances and wrenching design for use with both twelve spline and 12 point fasteners.”
The scope for SAE AS955 clearly shows the intention was for the sockets specified within to be used with 12 point fasteners, going so far as to reference ISO 4095 Aerospace - Bihexagonal drives - Wrenching configuration - Metric series.