A screw thread , often shortened to thread , is a helical structure used to convert between rotational and linear movement or force. A screw thread is an inclined plane wrapped around a cylinder or cone in the form of a helix, with the former being called a straight thread and the latter called a tapered thread. More screw threads are produced each year than any other machine element .[ 1]
Threads are generally produced according to one of the many standards of thread systems. Standards Development Organizations such as the American National Standards Institute , American Society of Mechanical Engineers , SAE International , International Organization for Standardization , Deutsches Institut für Normung (German Institute for Standardization), British Association and others produce these standards for manufacturers to follow when producing threaded components.
Currently used thread standards
Standard
Name
Type
Example
ASME B1.1-2003 (R2018)
Unified Inch Screw Threads (UN and UNR Thread Form) V Thread Form
1 ⁄4
ASME B1.5-1997 (R2014)
Acme Screw Threads
Trapezoidal Thread Form Tr 60×9
ANSI/ASME B1.9-1973 (R2017)
Buttress Inch Screw Threads
Breech-Lock Thread Form
ASME B1.10M-2004 (R2014)
Unified Miniature Screw Threads
V Thread Form
0.60 UNM
ANSI/ASME B1.11-1958 (R2016)
Microscope Objective Thread
V Thread Form
ASME B1.13M-2005 (R2015)
Metric Screw Threads: M Profile
V Thread Form
ASME B1.15-1995 (R2003)
Unified Inch Screw Threads (UNJ Thread Form)
V Thread Form
ASME B1.20.1-2013
Pipe Threads, General Purpose (Inch)
Pipe Thread Form
ANSI B1.20.3-1976 (R2013)
Dryseal Pipe Threads (Inch)
Pipe Thread Form
ASME B1.20.7-1991 (R2013)
Hose Coupling Screw Threads - Inch
Pipe Thread Form
ASME B1.21M-1997 (R2013)
Metric Screw Threads - MJ Profile
V Thread Form
BS 84
Tables of BS Whitworth , BS Fine and BS Pipe Threads
V Thread Form (55°)
1 ⁄4
ISO 68-1:1998
ISO general purpose screw threads—Basic profile—Part 1: Metric screw threads
V Thread Form
ISO 68-2:1998
ISO general-purpose screw threads—Basic profile—Part 2: Inch screw threads
V Thread Form
ISO 261:1998
ISO general purpose metric screw threads —General planV Thread Form
M6x1
ISO 262:1998
ISO general purpose metric screw threads—Selected sizes for screws, bolts and nuts
V Thread Form
ISO 724:1993
ISO general-purpose metric screw threads—Basic dimensions
V Thread Form
ISO 725:2009
ISO inch screw threads—Basic dimensions
V Thread Form 51386
DIN 40400
Edison Thread Round V Thread Form
Obsolete thread standards
See also
Notes
References
Degarmo, E. Paul; Black, J T.; Kohser, Ronald A. (2003), Materials and Processes in Manufacturing (9th ed.), Wiley, ISBN 0-471-65653-4 
