The Yato 173-piece Socket Set is a comprehensive mechanic's socket set, including tools with  1/4″, 3/8″, and 1/2″ drives. The sockets are manufactured by drop forging from durable CrV 50BV3 chrome vanadium steel and are calibrated with precision gauges before the hardening process. The design is optimized to withstand high stress and maintain tight tolerances over long-term use.

The sockets utilize an AS-Drive profile, which directs torque to the side surfaces of the fastener instead of the corners. This mechanical solution increases the maximum torque by 25% compared to standard profiles. Simultaneously, it prevents the rounding of nuts and bolts during demanding removals.

The bits and screwdriver bits included in the set are made from hard S2 tool steel, which has exceptionally high tensile strength and fracture resistance. The surfaces of the tools are finished with a two-tone coating that improves the corrosion resistance of the components in humid working environments.

The three ratchets supplied with the set are equipped with a 72-tooth (72T) mechanism. The fine tooth count provides a return angle of only 5 degrees. This specification is critical for usability in installations where working space is physically restricted.

Intended Use and Suitability:

The socket set is designed for technical environments requiring versatile fastener type management and standardized drive sizes.

• Vehicle Maintenance: Installation and disassembly of engine components, chassis parts, and brake systems, especially utilizing E-Torx and hex sockets.
• Industrial Maintenance: Mechanical maintenance of production machinery and conveyors, where the 72T ratchet mechanism enables efficient work in confined machinery spaces.
• Plumbing and Electrical Installations: Use of versatile bits and articulated extension bars for torquing fasteners in piping systems and equipment enclosures.

Package Contents:

The set includes a total of 173 pieces packed in a plastic case:

• 1/2″ parts: 6-point sockets 10-32 mm, deep 6-point sockets 16-22 mm, E-Torx E18-E24, spark plug sockets 16/21 mm, 72T ratchet, extension bars, universal joint, T-handle.
• 3/8″ parts: 6-point sockets 10-19 mm, deep 6-point sockets 10-15 mm, E-Torx E10-E16, spark plug socket 18 mm, 72T ratchet, extension bar, universal joint, adapter.
• 1/4″ parts: 6-point sockets 4-14 mm, deep 6-point sockets 4-10 mm, E-Torx E4-E8, 72T ratchet, T-handle, spinner handle, extension bars, universal joint.
• 1/4″ bits and sockets: Slotted, PH, PZ, Torx, Hex.
• 5/16″ bits: Torx (TX40-TX70), Hex (7-14 mm), XZN, Ribe, Slotted, PH, PZ.
• Other: L-shaped hex keys 1.25-5 mm.

Features:

The following structural features determine the performance of the tools:

• AS-Drive profile: Shifts the contact point from the corner of the nut to the side, increasing maximum torque by 25% and preventing fastener breakage.
• 72T Ratchet Mechanism: A 72-tooth gear provides a 5-degree working angle for tight mechanical installations.
• CrV 50BV3 material alloy: Chrome vanadium steel ensures thin yet unbreakable walls for the sockets even under high torque loads.
• Drop Forging: The manufacturing method maintains the fibrous structure of the metal, improving the fatigue strength and durability of the parts.

Technical Specifications:

• Total number of parts: 173 pcs.
• Drive sizes: 1/4″, 3/8″, 1/2″.
• Socket material: CrV 50BV3.
• Bit material: S2 tool steel.
• Ratchet gearing: 72 teeth (72T).
• Ratchet return angle: 5 degrees.
• Torque increase (AS-Drive): + 25 %.
• Surface treatment: Two-tone chrome plating.

Yato 173-piece Socket Set User Manual:

Ensure the longevity and safety of sockets by following correct mechanical principles during installation.

1. Select a socket that precisely matches the fastener to be installed. Ensure the correct unit system (metric vs. imperial).

2. Insert the socket onto the square drive of the ratchet handle so that the locking ball securely holds the socket in place.

3. Place the socket completely straight onto the bolt or nut to avoid the risk of breakage due to angled torque.

4. Apply torque smoothly without impacts. To ensure the durability of the ratchet mechanism, seized fasteners should be opened with a fixed T-handle instead of an articulated ratchet.

5. Clean tools from dirt and grease after use. The ratchet mechanism should be kept free of debris and occasionally lubricated with light machine oil.

Warnings:

Exceeding the mechanical limits of the tools can lead to equipment breakage.

• Hand tool status: Sockets and extension bars made of chrome vanadium steel must not under any circumstances be used with pneumatic or electric impact wrenches. Impact force poses a risk of shattering for CrV steel.
• Overtorquing: Do not extend the ratchet handle with a pipe or other tool to increase torque. The internal mechanism of the ratchet will break from overload.
• Electrical work: These tools do not have VDE electrical insulation. Tools must not be used for installing live parts.

Frequently Asked Questions, FAQ:

Can Yato YT-38931 set sockets be used with an impact wrench?
No. The sockets in this set are made of CrV 50BV3 steel, which is designed exclusively for continuous, steady torque. Using an impact wrench can break the socket and cause a hazardous situation. Impact wrenches require CrMo power sockets alloyed with molybdenum.

What is the technical advantage of the AS-Drive profile compared to a traditional 6-point socket?
In the AS-Drive profile, the inner corners of the socket are rounded. This shifts the torque application from the sharp corners of the nut to the flat sides, increasing torque capacity by 25% and allowing even slightly rounded bolts to be opened without further damage.

What material are the bits in the set made of, and how do they differ from the sockets?
The bits are made of S2 tool steel, while the sockets are CrV 50BV3 steel. S2 is a harder and more flexible material that better withstands the concentrated torsional stress encountered by small bits (such as Torx or hex) without fracturing.

Recycling Instructions:

All sockets, wrenches, bits, and extension bars in the set are fully recyclable steel and should be disposed of by taking them to a metal recycling point. The tool case should be sorted according to local guidelines for hard plastic collection or energy waste. Oil residues on metal parts do not prevent the recycling of steel by melting.