Slotted Nut Sizes and Dimensions Chart according to ASME B18.2.2-1987 standard.
Hex slotted nut is a hexagonal shape nut with slots on the top. These slots make
it possible to insert a split pin (or cotter pin) and secure the nut in place.
Heavy hex slotted nuts are slightly thicker and larger than
Hex slotted nuts. They are generally used for large diameter bolts.
Hex thick slotted nuts are higher than
Hex slotted nuts. They are generally used where longer engagement length is needed.
Some important notes from the ASME B18.2.2:
- The diameter range of hex slotted and hex thick slotted nuts is from ¼ to 1 1/2
inches according to standard. For heavy hex slotted nuts, the range is the range
is from ¼ to 4 inches.
- Threads shall be Unified inch coarse, fine or 8 thread series with tolerance class of 2B (UNC, UNF, or UN-8).
- Unless otherwise specified, chemical and mechanical properties of steel nuts shall conform
with ASTM A563 Grade A, Carbon and Alloy Steel Nuts; or
Grade 2 of SAE J995, Mechanical and Material Requirements for Steel Nuts. Nuts of
other materials such as stainless steel, brass, bronze, and aluminum
alloys shall have properties as agreed upon between the manufacturer and purchaser.
The properties for nuts of several grades of stainless steel alloys are
covered in ASTM F 594, and of several nonferrous materials in the ASTM F 467.
- Nuts in sizes 5/8 in. (for heavy ones, this size is 7/16 in.) nominal size and smaller shall
be double chamfered. Larger size nuts shall be double chamfered or have washer
faced bearing surface and chamfered top.
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.中国大黄页114在线
UNEF (Unified National Extra Fine):
Used when finer
pitches than UNF are needed (Ex: Short engagement length).
UNS (Unified National Special):
UNS are special series. Bolt / screw selection shall be done from standard series unless there is a special requirement to use a special series.
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.
Thread Gages and Gauging : Specifications and dimensions for the gages used on Unified inch screw thread is defined in the ANSI/ASME B1.2-1983 standard.
Types of gages including thread plug gages, snap gages, thread ring gages and
plain diameter gages for internal and external threads are covered in same
standard. Screw thread gauging systems for acceptability is covered in the ASME