5/16-32 UNEF Thread Specs
Standard: ASME B1.1 (UNEF)
Find the technical dimensions, threads per inch (TPI), and tapping guidelines for the 5/16-32 UNEF unified thread.
Compliant with the ASME B1.1 standard, this size has a nominal major diameter of 0.3125 inches (7.94 mm) with a pitch of 0.03125 inches (TPI of 32).
For general engineering or fastening, the standard recommended tap drill is 0.2813 inches (7.14 mm) to achieve adequate thread engagement.
Dimensional Specifications (Inches & mm)
Size Designation
5/16-32 UNEF
Major Diameter (Nominal)
0.3125 in(7.94 mm)
TPI (Threads per Inch)
32
Pitch
0.03125 in
Pitch Diameter
0.2922 in(7.42 mm)
Minor Diameter (Ext)
0.2787 in(7.08 mm)
Minor Diameter (Int)
0.2821 in(7.16 mm)
Thread Height
0.0271 in
Drilling & Strength Specs
Tap Drill Size
0.2813 in(7.14 mm)
Stress Area
0.0625 in²(40.31 mm²)
Quick Unit Converter
mm
⇄
inch
Frequently Asked Questions
What is the tap drill size for 5/16-32 UNEF?
The recommended tap drill size for a 5/16-32 UNEF thread is 0.2813 inches (approx. 7.14 mm) to achieve standard thread engagement.
How many threads per inch (TPI) does a 5/16-32 UNEF bolt have?
A standard 5/16-32 UNEF thread has exactly 32 threads per inch (TPI), with a corresponding linear pitch of 0.03125 inches.
What is the major diameter of a 5/16-32 UNEF thread in millimeters?
The nominal major diameter of a 5/16-32 UNEF thread is 0.3125 inches, which converts to 7.94 mm.