SOCKET PRODUCTS
Socket Products is a general term used to describe fasteners that have an internal recess drive. The most common type of internal drive recess is the hex socket (commonly called an Allen Screw). A second style of internal recess drive is the “Torx” socket (also called a six-lobe socket). The Torx socket provides a higher resistant to rounding out than a hex socket. This permits higher torques to be applied to the fastener than can be achieved with a hex key. Earnest provides the “Torx Plus” design that provides even greater resistance to rounding out over the original “Torx” design. Any customer currently using hex sockets will benefit by going to a Torx Plus socket.
Earnest also provides “Locking Elements” on its line of socket screws. Nylon applied to the threads provides added resistance to loosening when the screws are subjected to high vibration.
The five most common styles of fasteners that are classified as socket products are:
1. Socket Head Cap Screws:
Inch sizes of Socket Head Cap Screws do not have different strength levels like Hex Head Cap Screws. There is only one strength level when you are dealing with an alloy steel product(stainless steel socket screws are available, these are much lower in strength than alloy steelsocket screws).
The style of socket that Earnest carries is also called a 1960 series. This refers to the dimensionsof the head. The ANSI standard for sockets screws (B18.3) was changed in 1960. Sockets madeto the old standard are called 1936 series. The thread length for socket heads = 2 x Dia. + 1/2”.
The physical properties of the inch series socket head screws carried by Earnest are made to the requirements of ASTM A574.
Tensile Strength :Sizes 1/2” and smaller – 180,000 psi
Sizes larger than 1/2” – 170,000 psi
Hardness: Sizes 1/2” and smaller – Rc 39/45
Sizes larger than 1/2” – Rc 37/45
Earnest’s line of Metric Socket Head Cap Screws are made to the dimensional requirements ofANSI B18.3.3M and the physical properties meet the requirements of ASTM A574M for a Property Class 12.9. Thread length = 2 x Dia. + 12mm
Tensile Strength :All Sizes – 1220 MPa (176,900 psi)
Hardness:All Sizes – Rc 38/44
Note: Earnest line of 12 Point Flange Screws are designed to be used in any application that uses socket head cap screws. The 12 Point Head will fit into the same size counter bored hole as a socket head and the design permits the screws to be tightened using a 12 point socket which permits tighter assemblies to be achieved.
The next three styles of socket screws are intended for applications where a low profile head is required. The low profile head designs are intended for high shear applications and should not be used in applications that will subject them to high tensile forces or fatigue loads.
2. Low Profile Socket Head Cap Screws:
Earnest’s line of low head socket head cap screws have head heights that are less than half the height of a standard socket head. The physical properties are made to the requirements of ASTM F835. The hardness requirements of low profile socket screws are similar to a standard socket head screw (#1 above) but the low profile head is not as strong in tension (shear properties are equivalent).
Tensile Strength :Sizes 1/2” and smaller – 145,000 psi
Sizes larger than 1/2” – 135,000 psi
Hardness: All Sizes – Rc 38/44
3. Flat Head Socket Cap Screws:
Earnest’s line of Inch Series Flat Head Countersunk Socket Screws are made to the dimensional requirements of ANSI B18.3. The angle of the countersink under the head is82”. The physical properties are to ASTM F835. Flat head socket screws have similar hardness requirements as regular socket head screws (#1 above), but because the head design of a flat head is not as strong as that of a socket screw their minimum tensile strength is lower. Flat head screws also have thread lengths of 2 x Dia. + 1/2”.
Tensile Strength:Sizes 1/2” and smaller – 145,000 psi
Sizes larger than 1/2” – 135,000 psi
Hardness: All Sizes - Rc 38/44
Earnest’s line of Metric Flat Head Socket Head Cap Screws are made to the dimensional requirements of ANSI B18.3.5M. The angle of the countersink under the head is 90”.The physical requirements are to ASTM F835M.
Tensile Strength: All Sizes – 980 MPa (142,100 psi)Hardness: All Sizes – Rc 38/44Note: “Slotted Flat Head Screws are not made to the same standards as Socket Flat HeadScrews. Earnest provides a line of slotted screws that are manufactured to thedimensional requirements of ANSI B18.5 with physical properties that meet SAEJ429 Grade 5 requirements.
4. Button Head Cap Screws
Earnest’s line of Inch Series Button Head Socket Screws are made to the dimensional requirements of ANSI B18.3. The physical properties are to ASTM F835. Button head socket screws have similar hardness requirements as regular socket heads, but because the head design of a button head is not as strong as the socket screw their minimum tensile strength is lower. Button head screws also have a thread length of 2 x Dia + 1/2”
Tensile Strength: Sizes 1/2” and smaller – 145,000 psi
Sizes larger than 1/2” – 135,000 psi
Hardness: All Sizes – Rc 38/44
Earnest’s line of Metric Button Head Socket Head Cap Screws are made to the dimensional requirements of ANSI B18.3.5M. The physical requirements are to ASTMF835M.
Tensile Strength :All Sizes – 980 MPa (142,100 psi)
Hardness: All Sizes – Rc 38/44
5. Shoulder Screws
Earnest’s line of Socket Shoulder Screws are made to the dimensional requirements of ANSI B18.3. These screws are made from an alloy steel to the following physical properties.
Tensile Strength: All Sizes – 140,000 psi
Shear Strength: All Sizes - 84,000 psi
Hardness: All Sizes – Rc 32/43
Socket Shoulder screws are identified by the diameter and the length of the shoulder.
6. Socket Set Screws
Socket Set Screws are designed to lock collars, sprockets, gears and pulleys to shafts. Setscrews are designed to be loaded in compression. The compression loading developed by the set screw creates the locking action.
Set Screws are available with different point configurations. The different point styles are intended for different applications. Earnest provides a complete line of point styles.
The “cup point design is the most common design for set screws. The “knurled cup point” is an improvement over the standard cup point because it digs into the shaft better and provides better locking action. Any one using a “cup” point can improve its performance by going to a “knurled cup” point.
The “flat” and “oval points are for applications where you do not want the set screws to dig into the shaft.
The “cone and “half dog point is intended for applications where a slot or recess is located in the shaft and the set screws can be used for locating and locking.
Earnest provides products that solve the biggest problems with set screws. Either the socket rounds out or the set screws loosen in the application. All Earnest set screws are made from alloy steel and are through hardened. The combination of material and heat treat helps prevent socket round out. Earnest also offers set screws with the “Torx Plus”socket (six lobes). This socket design provides increased resistance to rounding out and also permits the set screw to be assembled to higher torques which greatly reduce their chance of loosening. Also available are set screws with locking patches that minimize the potential of loosening.
The material and physical properties of the set screws provided by Earnest are made to the requirements of ASTM F912.
Hardness: Rc 45/53
Because the shape of set screws make them impractical to be tested in a tensile tester,there is no specified minimum tensile strength for socket set screws. The minimum hardness that they are heat treated to corresponds to a minimum material strength of over 215,000 psi.