A split nut is a
nut that is split lengthwise into two pieces (opposed halves) so that its
female
An organism's sex is female ( symbol: ♀) if it produces the ovum (egg cell), the type of gamete (sex cell) that fuses with the male gamete (sperm cell) during sexual reproduction.
A female has larger gametes than a male. Females and ...
thread may be opened and closed over the
male
Male (Planet symbols, symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or Egg cell, ovum, in the process of fertilisation. A male organism cannot sexual repro ...
thread of a
bolt or
leadscrew. This allows the nut, when open, to move along the screw without the screw turning (or, vice versa, to allow the screw to pass through the nut without turning). Then, when the nut is closed, it resumes the normal movement of a nut on a screw (in which axial travel is linked to
rotational travel)
A split nut assembly is often used in positioning systems, for example in the
leadscrew of a
lathe. It is one of the
machine element
Machine element or hardware refers to an elementary component of a machine. These elements consist of three basic types:
# ''Structural element, structural components'' such as frame members, Bearing (mechanical), bearings, axles, Spline (mechan ...
s that makes
single-point threading practical on manual (non-
CNC) lathes. The very earliest
screw-cutting lathes (in the late 18th and early 19th centuries) did not have them, but within a few decades, split nuts were common on lathes.
The two halves of the nut have
chamfered ends (60° to the axis), which helps the threads to find engagement during the closing action. Usually, the screw and nut are also
oiled for lubrication. Such provisions prolong the service life of the threads by minimizing
wear
Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical (e.g., erosion) or chemical (e.g., corrosion). The study of wear and related processes is referred to as tribology.
Wear in ...
.
Split nuts work best with
trapezoidal threads.
Split nuts may not engage and disengage with
multi start threads due to the overlapping leads.
References
Nuts (hardware)
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