Drive Sockets and Adapters Information

Drive SocketDrive sockets and adapters include individual products and packaged sets of removable wrench and interchangeable bit screwdriver attachments. They are designed to accommodate a variety of nut, bolt, and screw sizes, as well as tool-access restrictions.

In addition to product type, bit and socket style, the material finish, product specifications, features, and application are important to consider.


Drive sockets and adapters include:


Removable sockets are designed for use with a T-handle that allows operators to apply more torque and access hard-to-reach areas. They are usually made of steel and may be treated to prevent wear and corrosion.




Wrench extenders are made of metals with a high tensile strength and are used to remove rusted, frozen, or over-tightened nuts. They provide mechanics with an alternative to hammering on a wrench, using a pipe, or hooking two wrenches together. Force applied to the handle applies torque to the nut or bolt, allowing these fasteners to be driven even in difficult positions.

Wrench Extension. Image



To calculate the length extension needed, the following formula can be used:



wrench setting = τdesired x Lwrench / (Lwrench + Lextension)



            τdesired - torque needed to complete job

            Lwrench - length of original wrench

            Lextension - length added to the wrench.


The wrench setting is the torque needed to apply the desired torque.

For example, if the length of the torque wrench is 15 inches, the length of the extension is 9 inches, and the desired torque is 160 ft-lbs:


Wrench setting  = 160 x 15 / (15 +9)

                         = 160 x 15 / (24)

                         = 100 ft-lbs


If the torque wrench is set to 100 ft-lbs, the actual torque applied to the bolt will be 160 ft-lb.



Screwdriver bit-adapters include attachments for a variety of applications.


Universal joint adapters allow a handle or extension to be placed at an angle so work to be done around obstacles and by a socket wrench.


Socket adapters are used to adapt the drive size of a socket for use with a wrench with a different drive size. For example, a socket adapter can be used to adapt a socket with a 1/4" square drive for use with a wrench with a 3/8" square drive.


Socket extensions are used to extend the reach of a socket.


Socket Extender. Image Credit:



Flexible extensions extend the reach of a socket. They are flexible to access sockets in hard to reach locations.



Flex/hinge handle contains a clevis style joint at the end which the socket is assembled to.




Hinge Handle. Image Credit: nkbaxter

Bit and Socket Styles

Bits and sockets are selected based on their size, shape and the intended application. There are several styles of bits and sockets which include:


Phillips Bit


Socket used for driving a screw with a Phillips drive. Standard Phillips sizes are 0, 1, 2, 3, and 4. The bit prevents assemblers from tightening screws so tightly that the threads strip. 




Pozidriv® Bit


Socket used for driving a screw with a Pozidriv® drive. Pozidriv is an improvement to the Phillips drive and is jointly patented by the Phillips Screw Company and American Screw Company. Pozidriv bits have a second cross-like structure at 45 degrees to the primary cross. 




Slotted Bit


Socket contains a slotted bit, used for driving a screw with a slotted drive. They are easy to adapt to in the work room because matching driver tips can be created using files and a new slot can be cut with a hacksaw. Camming out1 is easy to do, and the screwdriver does not automatically line up with the slot.





Torx® Bit



Socket used for driving a screw with a Torx drive.  A Torx drive has a six-point star-shaped pattern.  Sizes for a screw head with a Torx drive start with the letter "T", followed by a number. 




Standard / Shallow Length Socket 


Socket has a standard length, also referred to as a shallow length. Standard length sockets have a fairly low profile and are used to access nuts in narrow spaces. 


Deep Length Socket


Socket has a deep length, which is longer than that found in a standard socket.  Deep sockets are commonly used for turning a nut onto a bolt when the bolt extends beyond the nut. 


Impact Socket


Impact sockets are used with high strength fasteners when a higher tightening torque is required.  Standard sockets are made from a strong, brittle steel and would break if used with an impact wrench.  Impact sockets are made from thicker and weaker malleable steel. 




Product contains a swivel between the socket opening and the socket drive that allows for angular movement of the wrench.  Swivel sockets are used in difficult to reach applications and are found on sockets, socket extensions and socket adapters. 




Insulated sockets are used to protect the operator from electrical shock.


Spark Plug Socket


Spark plug sockets are specially designed for the installation and removal of spark plugs.

Material Finish

The finish of a drive socket and adapter plays an important role in the functionality and life expectancy of the product. Material finish processes include:


Galvanized steel is the result of a chemical process that protects the material from corrosion by coating the steel in zinc, and oxidation resistant material.


Magnetic materials produce magnetic field which attract other metals. Drive sockets and adapters with magnetic properties are used to assist in holding fasteners in place during assembly and removal.


Heat-treated metals undergo a controlled heating and cooling process which alters their physical and mechanical properties without changing the product shape. The process is often used to increase the strength of the material.


Anti-corrosion finishes are done by metal or thermal spraying technologies. They protect and extend the life of products by coating them with aluminum, zinc or a zinc/aluminum alloy.


Product Specifications


The number of points in a socket determines the shape and number of starting points available. The twisting action of the socket applies most of the torque at or near the corners of the head; greater torque can be achieved with more points

  • 4: The socket has four points. Four point sockets are used for square shaped bolt heads and nuts.
  • 6: The socket has ahexagon shape and containssix points. Six point sockets provide better grip than 12 point sockets and therefore have less slippage and rounding off of the fastener points. Six point sockets are used for hex shaped bolt heads and nuts and can be used on a thicker, stronger socket.
  • 8: The socket has an eight points. Eight point socketsare used for squareshaped bolt heads and nuts but have become less popular.
  • 12: The sockethas twelve points. Twelve point socketsare used for hex shaped bolt heads and nuts and are faster and more versatile.


Many drive sockets and adapters come with a lifetime guarantee from the manufacturer.

Drive sockets and adapters can be purchased as individual sockets or as socket sets that come with a variety of sizes and fittings.

Socket sets can come in a variety of combinations


  • Sockets only
  • Bits only
  • Sockets and bits



Socket Set. Image Credit: Digi-key


Duffy, James E., Robert Scharff, and Robert Scharff. Auto Body Repair Technology. Clifton Park, NY: Thomson/Delmar Learning, 2004. Print.

What is Galvanized Steel?

Objectives of Heat Treatments

Anti-Corrosive Finishing

Screw drive systems

Socket wrench

Image Credit: All-Spec


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