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Westfield Fasteners Product Specification:

DIN 934 - Full Hex Nuts With Left Hand Thread

This specification covers metric threaded full hex nuts with a left hand thread. These items are a standard part available from Westfield Fasteners. The basis of this specification is the DIN standard DIN 934.

Product Description
Hexagon full nut with standard metric coarse pitch, but with a less common left handed Thread. Like the more usual right hand threaded versions, these nuts are manufactured to DIN 934, and can only be used in conjunction with left hand thread screws, bolts and studs.

Designed for fitment with a spanner or ratchet with socket, and can be used in conjunction with hexagon left handed thin nuts in a "locking" formation for a more secure fitment.

Left handed hex nuts are also known as reverse nuts and are used where rotational forces and vibration could encourage a right handed nut to loosen. An example of use would be to retain a lawn mower's blade.
Scope of the DIN Standard.
DIN 934 governs the dimensions, tolerances and general form of hexagon full nuts, for sizes from M1 up to and including M160. Figure 1 and table 1 below give this information for all sizes of left hand thread full nuts in general circulation. Although the DIN 934 standard has now been superceded by ISO 4032, off the shelf parts are generally still manufactured to the older specification.

This standard generally applies to the usual right hand metric thread versions with a standard metric coarse pitch, as well as various fine pitches. This standard is also used for left hand thread items, both standard metric coarse covered here, and any fine pitch left hand versions that might be available.


technical drawing of full hex nut with left hand thread, to DIN 934

Figure 1: Full Hex Nuts With Left Hand Thread

Variations from DIN 934
DIN 934 covers materials including carbon steel, and A2 & A4 stainless steel. The hex nuts we stock in other materials and grades are made with reference to this standard, but are not mentioned specifically.







Table 1: Dimensions & Tolerances according to DIN 934 (mm)

Thread, dM3M4M5M6M8M10M12M14M16M18M20M22M24M27M30
Standard Pitch, p0.50.70.81.001.251.51.75222.52.52.5333.5
damin3456810121416182022242730
max3.454.65.756.758.7510.81315.117.319.521.623.725.929.132.4
dwmin4.55.86.88.811.315.317.220.222.225.328.229.533.23842.7
emin6.017.668.7911.0514.3818.9021.1014.4926.7529.5632.9535.0339.5545.250.85
mnom=max2.43.2456.58101113151618192224
min2.152.93.74.76.147.649.6410.312.314.314.916.917.720.722.7
snom=max5.578101317192224273032364146
min5.326.787.789.7812.7316.7318.6721.6723.6726.1629.1631354045


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