2″ bolt dimensions and screw sizes are essential for heavy civil engineering, power plant infrastructure, and massive industrial hydraulic assemblies. This size is standardized with a 2.000″ nominal major diameter and is available in 2″-4.5 coarse (UNC) thread pitch, representing 4.5 threads per inch (TPI). This reference chart follows ANSI/ASME B18.6.3 and B18.3 standards for the head size and ANSI/ASME B1.1 standards for the thread dimensions to ensure compatibility across extra-large imperial fastening applications.
Disclaimer: Dimensions and tolerances may vary slightly depending on head style, manufacturer, or material — always verify with the official product datasheet before use.
2-4.5 UNC Screw & Bolt – ANSI/ASME B1.1
Dimension
Size (in)
Min
Max
Major Diameter
1.9641
1.9971
Pitch Diameter
1.8385
1.8528
Minor Diameter
Not specified
1.7325
Threads Per Inch (TPI)
4.5
Major Diameter
1.9751
1.9971
Pitch Diameter
1.8433
1.8528
Minor Diameter
Not specified
1.7325
Threads Per Inch (TPI)
4.5
Major Diameter
1.978
2
Pitch Diameter
1.8486
1.8557
Minor Diameter
Not specified
1.7354
Threads Per Inch (TPI)
4.5
2-6 UN Screw & Bolt – ANSI/ASME B1.1
Dimension
Size (in)
Min
Max
Major Diameter
1.9792
1.9974
Pitch Diameter
1.8805
1.8891
Minor Diameter
Not specified
1.7989
Threads Per Inch (TPI)
6
Major Diameter
1.9818
2
Pitch Diameter
1.8853
1.8917
Minor Diameter
Not specified
1.8015
Threads Per Inch (TPI)
6
2-8 UN Screw & Bolt – ANSI/ASME B1.1
Dimension
Size (in)
Min
Max
Major Diameter
1.9827
1.9977
Pitch Diameter
1.9087
1.9165
Minor Diameter
Not specified
1.8489
Threads Per Inch (TPI)
8
Major Diameter
1.985
2
Pitch Diameter
1.913
1.9188
Minor Diameter
Not specified
1.8512
Threads Per Inch (TPI)
8
2-12 UN Screw & Bolt – ANSI/ASME B1.1
Dimension
Size (in)
Min
Max
Major Diameter
1.9868
1.9982
Pitch Diameter
1.938
1.9441
Minor Diameter
Not specified
1.899
Threads Per Inch (TPI)
12
Major Diameter
1.9886
2
Pitch Diameter
1.9414
1.9459
Minor Diameter
Not specified
1.9008
Threads Per Inch (TPI)
12
2-16 UN Screw & Bolt – ANSI/ASME B1.1
Dimension
Size (in)
Min
Max
Major Diameter
1.989
1.9984
Pitch Diameter
1.9524
1.9578
Minor Diameter
Not specified
1.924
Threads Per Inch (TPI)
16
Major Diameter
1.9906
2
Pitch Diameter
1.9554
1.9594
Minor Diameter
Not specified
1.9256
Threads Per Inch (TPI)
16
2-20 UN Screw & Bolt – ANSI/ASME B1.1
Dimension
Size (in)
Min
Max
Major Diameter
1.9904
1.9985
Pitch Diameter
1.9611
1.966
Minor Diameter
Not specified
1.939
Threads Per Inch (TPI)
20
Major Diameter
1.9919
2
Pitch Diameter
1.9638
1.9675
Minor Diameter
Not specified
1.9405
Threads Per Inch (TPI)
20
Major Diameter –
The largest diameter of the external thread, measured crest to crest.
This defines the nominal size of the screw or bolt.
Pitch Diameter –
The diameter of an imaginary cylinder where the thread thickness equals
the space between threads. This dimension primarily controls thread fit
and tolerance class of 2A and 3A.
Minor Diameter –
The smallest diameter of the external thread, measured root to root.
This affects thread strength and clearance.
Threads Per Inch (TPI) –
The number of complete threads within one inch of thread length.
Higher TPI values indicate a finer thread pitch.
What is the difference between a bolt and a screw?
The difference is based on the intent of the fastener’s use; If the primary intent is for the fastener to pass through an unthreaded holes and be assembled with a nut, it is a Bolt. In this application, you usually hold the head and turn the nut to apply tension. But if the primary intent is for the fastener to be installed into a threaded (tapped) hole, it is a Screw. In this application, the connection is tightened by turning the head of the fastener itself.
