Thread Pitch Chart
Measuring Threads by Pitch
Measuring Threads Per Inch (TPI)
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METRIC THREADS Pitch (mm) Size Coarse Fine Extra Fine M1.6 0.35 M2 0.40 M2.5 0.45 M3 0.50 M3.5 0.60 M4 0.70 M5 0.80 M6 1.00 M7 1.00 M8 1.25 1.00 M10 1.50 1.25 1.00 M12 1.75 1.50 1.25 M14 2.00 1.50 M16 2.00 1.50 M18 2.50 1.50 M20 2.50 1.50 M22 2.50 1.50 M24 3.00 2.00 1.50 M27 3.00 2.00 M30 3.50 2.00 M33 3.50 2.00 M36 4.00 3.00 M39 4.00 3.00 M42 4.50 M45 4.50 M48 5.00 M52 5.00 M56 5.50 M60 5.50 M64 6.00 M72 6.00 M80 6.00 M90 6.00 M100 6.00 -
AMERICAN INCH THREADS Threads per Inch (TPI) Size UNC UNF UN8 #0 80 #1 64 72 #2 56 64 #3 48 56 #4 40 48 #5 40 44 #6 32 40 #8 32 36 #10 24 32 #12 24 28 #1/4” 20 28 5/16” 18 24 3/8” 16 24 7/16” 14 20 1/2” 13 20 9/16” 12 18 5/8” 11 18 3/4” 10 16 7/8” 9 14 1” 8 14/12 8 1-1/8” 7 12 8 1-1/4” 7 12 8 1-3/8” 6 12 8 1-1/2” 6 12 8 1-5/8” 8 1-3/4” 5 8 1-7/8” 5 8 2” 4.5 8 2-1/4” 4.5 8 2-1/2” 4 8 2-3/4” 4 8 3” 4 8 3-1/4” 4 8 3-1/2” 4 8 3-3/4” 4 8 4” 4 8 -
BRITISH INCH THREADS Threads per Inch (TPI) Size BSW BSF BA 8BA 59.1 6BA 47.9 1/8” 40 5BA 43 4BA 38.5 3BA 34.8 2BA 31.4 3/16” 24 32 32 1BA 28.2 0BA 25.4 1/4” 20 26 9/32” 26 5/16” 18 22 3/8” 16 20 7/16” 14 18 1/2” 12 16 9/16” 12 16 5/8” 11 14 11/16” 14 3/4” 10 12 7/8” 9 11 1” 8 10 1-1/8” 7 9 1-1/4” 7 9 1-3/8” 7 8 1-1/2” 6 8 1-5/8” 5 8 1-3/4” 5 7 2” 4.5 7 2-1/4” 4 6 2-1/2” 4 6 2-3/4” 3.5 6 3” 3.5 5 3-1/4” 3.25 5 3-1/2” 3.25 4.5 3-3/4” 3 4.5 4” 3 4.5
