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Westfield Fasteners Product Specification:

Hexagon Socket Head Cap Screws with Low Head, to DIN 7984

This product guide contains the specification for metric threaded socket low head cap screws as available from Westfield Fasteners. The basis of this specification is the DIN standard DIN 7984.

Product Description
Similar to the DIN 912 socket cap screw but with a lower head height and smaller hex drive, the DIN 7984 is used where space is limited. Please note that thread lengths on partial threaded shanks are a minimum, and consequently a full thread may be supplied where a partial thread is indicated by the data.

Scope of the DIN standard.
DIN standard 7984 specifies the tolerances and the permissable variation in form of hexagon socket cap low head screws, and covers metric thread diameters from M3 up to and including M24. Mechanical properties for these items are defined in ISO 898 and ISO 3506. Table 1 below defines the overall dimensions and tolerances of this screw type. Table 2 defines the tolerances on the shank length, whilst tables 3 and 4 show the reduced minimum ultimate tensile loads for class 8.8 and stainless steel variants respectively of this product. The information in tables 3 and 4 is presented here because due to their head design socket low head cap screws are considered to have reduced loadability over other screw types, as defined in ISO 898 and ISO 3506.



















technical drawing of Hexagon Socket Head Cap Screws with Low Head, to DIN 7984

Figure 1: Socket Head Low Cap Screw

Figure 1: Socket Head Low Cap Screw

Notes to figure 1:



Variations from DIN 7984
Socket low cap head screws are available in class 10.9 high tensile steel, but this class/grade is not mentioned in the DIN 7984 standard. Again, due to the reduced size of the head, these screws are considered to have reduced loadability over other screw types of this material class, and will typically be 80%.

Manufacturer and/or material markings may be present on the top face of the head.

DIN 7984 | Socket Cap Screws Low Head


Table 1: Dimensions & Tolerances according to DIN 7984

Thread, dM3M4M5M6M8M10M12M14M16M18M20M22M24
thread pitch (standard metric coarse)0.50.70.811.251.51.75222.52.52.53
minimum thread lengthb for shank length ≤ 12512141618222630343842465054
b for shank length > 125 and ≤ 200----283236404448525660
b for shank length > 200--------5761656973
bearing face inner diameterda max.3.64.75.76.89.211.213.715.717.720.222.424.426.4
head diameterdk max.=nominal size5.578.510131618212427303336
dk min.5.326.788.289.7812.7315.7317.7320.6723.6726.6729.6732.6135.61
unthreaded shank diameterds max.=nominal size345681012141618202224
ds min.2.863.824.825.827.789.7811.7313.7315.7317.7319.6721.6723.67
bearing face outer diameterdw min.4.846.207.709.2012.0315.0317.0319.8322.8325.8328.8331.6123.67
socket width across cornerse min.2.302.873.444.585.728.019.1511.4313.7213.72161619.44
transition lengthlf max.0.510.600.600.681.021.021.871.871.871.872.042.042.04
head heightk max. =nominal size2.02.83.54.05.06.078910111213
k min.1.862.663.323.824.825.826.787.788.789.7810.7311.7312.73
underhead radiusr min.0.10.20.20.250.40.40.60.60.60.60.80.80.8
socket width across flatss, nominal size22.534578101212141417
s min.2.022.523.024.025.027.0258.02510.02512.03212.03214.03214.03217.050
s max.2.102.603.104.125.147.1758.17510.17512.21212.21214.21214.21217.230
socket deptht, nominal size1.52.32.733.84.555.35.56.57.588
t min.1.382.182.582.883.654.354.855.155.356.327.327.827.82
t max.1.622.422.823.123.954.655.155.455.656.687.688.188.18
head edge radius / chamferv max.0.30.40.50.60.811.21.41.61.822.22.4

DIN 7984 | Socket Cap Screws Low Head

Table 2: Shank Length Tolerance according to DIN 7984

Shank Length (mm)+/- (mm)
5-60.24
8-100.29
12-180.35
20-300.42
35-500.5
55-800.6
90-1000.7


Table 3: Minimum Ultimate Tensile Loads for Steel Screws of Property Class 8.8

Thread, dMinimum ultimate tensile load in N
M33220
M45620
M59080
M612900
M823400
M1037100
M1253900
M1473600
M16100000
M18127000
M20162000
M22202000
M24234000


Table 4: Minimum Ultimate Tensile Loads for Stainless Steel Screws

Thread, dFm, min kN
M32.82
M44.92
M57.95
M611.28
M820.48
M1032.48
M1247.20
M1464.40
M1688.00
M18107.20
M20137.60
M22169.60
M24197.60


For further details, please refer to the ISO/DIN standard document for this item.