Acorn Nut Sizes and Dimensions Chart for
SAE recommended low and high crown acorn nuts. The charts of acorn nuts are
given in the SAE J483a standard.
Acorn nut is a type of nut used with bolts to clamp the parts together. The
difference between hex nuts and acorn nut is that acorn nuts are closed nuts and
they protect male threads. Acorn nuts are also used for decorative purposes.
There are two types of acorn nuts which are low crown and high crown.
Some important notes from the SAE J483a:
- The diameter range of acorn nuts is from 0.1380 to 1.2500 inches according
- Threads are Unified Standard Class 2B, UNC or UNF Series.
Unified Screw Thread: A thread
form used by the United Kingdom, Canada, and the United States to obtain screw
thread interchangeability among these three nations. It has 60° thread angle and
dimensions are stated in inch units.
UN form screw threads: The UN
thread is intended for general purpose fastening operations.
UNC (Unified National Coarse):
Most commonly used type for general engineering applications. This thread form
is used in materials with low tensile strength which makes threads more
resistance against stripping (internal threads) .UNC give possibility for quick assembly.
UNF (Unified National Fine): External
threads of this Fine Series have greater tensile stress area than comparable sizes of the
coarse series. The Fine series is suitable when the resistance to stripping of both external
and mating internal threads equals or exceeds the tensile load carrying capacity of the
externally threaded member. It is also used where the length of engagement
is short, where a smaller lead angle is desired, where the wall thickness demands a fine
pitch, or where finer adjustment is needed.
Thread class: A classification system to classify the threads for
interchangeability and manufacturability. Class 1 threads are loosely fitting
thread and used for ease of assembly. Most commonly used class is 2 and this
class is designed for general use. Class 3 is used for closer tolerances.