engineering fundamentals Constant Pitch Unified Screw Threads
Directory | Career | News | Standards | Industrial | SpecSearch®

Design Home
Screw Threads
Thread System
Unified Screw Threads
Constant Pitch Series
  4 UN and 4 UNR
  6 UN and 6 UNR
  8 UN and 8 UNR
  12 UN and 12 UNR
  16 UN and 16 UNR
  20 UN and 20 UNR
  28 UN and 28 UNR
  32 UN and 32 UNR
Metric Screw Threads
Torque in Bolts
Introduction
Torque Calculator
Resources
Bibliography


Login

Home Membership Store Forum Search Member Calculators

Materials

Design

Processes

Units

Formulas

Math
Constant Pitch Series
 
Constant Pitch Series, The constant pitch series, UN, have 4, 6, 8, 12, 16, 20, 28, and 32 threads per inch. These are available for use when the Coarse, Fine, Extra-Fine Series do not meet the design requirements. Within these series, preference should be given to the 8, 12, and 16 thread series.
 
The 8 Thread Series, 8-UN is used for large diameters(greater than 1 inch) with a coarse thread. It was originally developed for use in high pressure joint bolts and nuts.
 
The 12 Thread Series, 12-UN is used for large diameters with a medium pitch thread. It was originally intended for use pressure vessels, such as boilers. It is currently used as a fine pitch series extension for diameters larger than 1½ inches.
 
The 16 Thread Series, 16-UN is used for large diameters with fine pitch threads. It is used for adjusting collars and retaining nuts and can be considered as an extension of the extra fine thread series for diameters larger than 111/16 inches.
 
The 4-UN, 6-UN, 20-UN, 28-UN and 32-UN Thread Series are used for those applications where the Standard Coarse, Fine or Extra Fine Series are not not a good choice.
 
Home  Membership  About Us  Privacy  Disclaimer  Contact  Advertise

Copyright © 2009 eFunda, Inc.