Screw chart size
Screws are a commonly used fastener in a variety of applications and come in a wide range of sizes.
The size of a screw is determined by the diameter of its shank, which is the portion of the screw between the threads and the head.
In addition to the size of the screw, which is determined by the diameter of the shank, the thread size is another important consideration.
The thread size refers to the distance between the threads, measured in millimeters or inches.
This below table that presents the measurements of various screw sizes in both inches (decimals as well as fractions) & millimeters.
Additionally, another table on right side is provided that shows the number of threads per inch for different screw and bolt sizes, including both coarse (UNC) & fine (UNF) thread types.
A common thread size for small screws is M3, which has a distance of 0.5mm between threads.
As the screw size increases, so does the thread size. For example, a #6 screw may have a thread size of M4, while a #8 screw may have a thread size of M5.
When selecting a screw, it’s important to keep in mind the thread size, thread pitch, and shank size to ensure a proper fit.
Specialized screws may also have different thread sizes, such as wood screws which are tapered and have a different thread pattern.
How do you read a thread size chart?
A thread size chart typically lists the various thread types and their corresponding thread sizes.
To read a thread size chart, you need to understand the different elements of a thread size designation.
A thread size is typically composed of two parts: the thread diameter and the thread pitch.
The thread diameter is the nominal size of the thread, while the thread pitch is the distance between threads measured in millimeters (mm) or threads per inch (TPI).
For example, a thread size of M14 x 1.5 would have a diameter of 14mm and a pitch of 1.5mm.
Similarly, a thread size of 3/4-16 would have a diameter of 3/4 inch and a pitch of 16 TPI.
Thread size charts usually have the thread type, thread size, thread diameter, thread pitch and other information.
What are the sizes of screws?
Here is a table of some of the commonly used screw sizes and their corresponding diameter measurements:
| Screw Size | Diameter (inches) | Diameter (mm) |
|---|---|---|
| #4 | 0.112 | 2.8 |
| #6 | 0.13 | 3.3 |
| #8 | 0.164 | 4.2 |
| #10 | 0.190 | 4.8 |
| #12 | 0.216 | 5.5 |
| #14 | 0.250 | 6.4 |
| #16 | 0.276 | 7.0 |
| #18 | 0.311 | 7.9 |
What are standard thread sizes?
Standard thread sizes vary depending on the thread type. Following are the standard thread sizes for various thread types:
| Thread Type | Thread Size |
|---|---|
| UNF (Unified National Fine) | #0 – #10 |
| UNC (Unified National Coarse) | 1/4″ – 1″ |
| UNEF (Unified National Extra Fine) | #00 – #4 |
| UNS (Unified National Special) | 1/4″ – 1″ |
| BSW (British Standard Whitworth) | 1/16″ – 1″ |
| BSF (British Standard Fine) | 1/16″ – 1″ |
| BSP (British Standard Pipe) | 1/8″ – 4″ |
| NPT (National Pipe Taper) | 1/8″ – 4″ |
| M (Metric) | M1.6 – M150 |
