1-1/2-12 UNF Thread Specs
Standard: ASME B1.1 (UNF)
Find the technical dimensions, threads per inch (TPI), and tapping guidelines for the 1-1/2-12 UNF unified thread.
Compliant with the ASME B1.1 standard, this size has a nominal major diameter of 1.5 inches (38.1 mm) with a pitch of 0.08333 inches (TPI of 12).
For general engineering or fastening, the standard recommended tap drill is 1.4167 inches (35.98 mm) to achieve adequate thread engagement.
Dimensional Specifications (Inches & mm)
Size Designation
1-1/2-12 UNF
Major Diameter (Nominal)
1.5 in(38.1 mm)
TPI (Threads per Inch)
12
Pitch
0.08333 in
Pitch Diameter
1.4459 in(36.73 mm)
Minor Diameter (Ext)
1.4098 in(35.81 mm)
Minor Diameter (Int)
1.4188 in(36.04 mm)
Thread Height
0.0722 in
Drilling & Strength Specs
Tap Drill Size
1.4167 in(35.98 mm)
Stress Area
1.581 in²(1020.01 mm²)
Quick Unit Converter
mm
⇄
inch
Frequently Asked Questions
What is the tap drill size for 1-1/2-12 UNF?
The recommended tap drill size for a 1-1/2-12 UNF thread is 1.4167 inches (approx. 35.98 mm) to achieve standard thread engagement.
How many threads per inch (TPI) does a 1-1/2-12 UNF bolt have?
A standard 1-1/2-12 UNF thread has exactly 12 threads per inch (TPI), with a corresponding linear pitch of 0.08333 inches.
What is the major diameter of a 1-1/2-12 UNF thread in millimeters?
The nominal major diameter of a 1-1/2-12 UNF thread is 1.5 inches, which converts to 38.1 mm.