Use the first number to figure out the diameter of the threads.

1. For example, on a #4-40 UNC-3A x . 5 screw, #4 represents the diameter.
2. The diameter is sometimes listed as a fraction, such as ¼. It has a diameter of 1⁄4 in (0.64 cm).
3. To help decipher the number ratings, look up a conversion chart online.

## Is UNF the same as NPT?

UNF is Unified Fine thread, the successor to the obsolete National Fine (NF) thread. NPT National pipe thread is used (in the U.S.) for plumbing of water and gas pipes, and threaded electrical conduit. NPT is defined by ANSI/ASME standard B1. NPTF is National Pipe Thread Fuel according to ANSI/ASME B1.

What size is a 2 56 screw?

Screw Size Class Thread Major Diameter
2-56 2A 0.0860
2-56 3A 0.0860
2-64 2A 0.0860
2-64 3A 0.0860

### What is UNF fitting?

UNC: Is the symbol for Unified coarse pitch threads. UNF: Is the symbol for Unified fine pitch threads. UNEF: Is the symbol for United extra fine pitch threads. UNS: Is the symbol for Unified special threads.

### What does UNF mean in thread size?

Coarse Thread (UNC) Fine Thread (UNF) Pitch Size TPI Size TPI Size TPI Size TPI Size Coarse Fine #1 64 1 8 #0 80 7/8 14 M4 0.70 0.50.

What are the sizes of metric threads?

Metric Threads. Coarse Thread (UNC) Fine Thread (UNF) Pitch Size TPI Size TPI Size TPI Size TPI Size Coarse Fine #1 64 1 8 #0 80 7/8 14 M4 0.70 0.50. #2 56 1 1/8 7 #1 72 1 121 M5 0.80 0.50.

#### What is the tap chart UNC/UNF threads?

Tap Chart UNC/UNF Threads – provides tap sizes, drill sizes, pitch, (threads per inch) basic major diameter, basic effective diameter, basic minor diameter of external threads, and basic minor diameter of internal threads for UNC/UNF threads Tap Chart UNC/UNF Threads Tap Chart – UNC/UNF Threads

#### What is the TPI of a 3B internal thread?

External Thread /Internal Thread Nominal Size, TPI, Series Class Allowance Min Pitch Ext. 0-80 UNF 2A 0.0005 0.0496 Int. 2B 0.0519 Ext. 0-80 UNF 3A 0.0000 0.0506 Int. 3B 0.0519