Long before wood screws were a thing, carpenters were using adhesives, nails, and wood joints to fuse to or more segments. Each technique had its disadvantages and advantages. However, the inception of this new wood fastener introduced a new way of fastening and mounting.
Wood screws work with hardwood, chipboard, MDF, and softwood. Several types are available in the market, which have different features. Most have safety features, such as the following:
- Avoid wood splitting through shanks
- Effective driving through twin threads
- Sharp tips will no longer need you to pre-drill
You can purchase these items in different head shapes and drive types. Each one is best for a specific application. Manufacturers initially use steel or bras to produce these items. The shaft has an increasing thickness from the tip to the head.
These fasteners have several thicknesses and lengths. We are covering everything you need about wood screw size charts, types, and some practical applications.
Wood screw size charts
The tables below shows the typical measurements. Slight variations are possible depending on the type.
Here are the wood screw size charts you need
| “A” Flat Head | “A” Flat Head | “A” Pan Head | “A” Pan Head | “A” Pan Head | “A” Round Washer Head | “A” Round Washer Head | “A” Round Washer Head | “B” Body Dia | “B” Body Dia | “C” Thread Dia | “C” Thread Dia | |
| Size | Min | Max | Min | Max | T max | Min | Max | T max | Min | Max | Min | Max |
| 4 | 0.195 | 0.225 | 0.205 | 0.219 | 0.086 | N/A | N/A | N/A | 0.084 | 0.095 | 0.105 | 0.116 |
| 6 | 0.244 | 0.279 | 0.256 | 0.27 | 0.103 | N/A | N/A | N/A | 0.107 | 0.118 | 0.131 | 0.142 |
| 8 | 0.292 | 0.332 | 0.306 | 0.322 | 0.12 | 0.352 | 0.376 | 0.11 | 0.125 | 0.136 | 0.157 | 0.168 |
| 10 | 0.34 | 0.385 | 0.357 | 0.373 | 0.137 | 0.411 | 0.443 | 0.125 | 0.146 | 0.157 | 0.183 | 0.194 |
| 12 | 0.389 | 0.438 | 0.407 | 0.425 | 0.153 | N/A | N/A | N/A | 0.165 | 0.176 | 0.209 | 0.22 |
| 14 | 0.452 | 0.507 | 0.473 | 0.492 | 0.175 | N/A | N/A | N/A | 0.19 | 0.201 | 0.235 | 0.246 |
Gauge
| Screw Gauge | Head diameter (mm) | Shank diameter (mm) |
| 0000 | 2.74 | 1.37 |
| 000 | 2.89 | 1.44 |
| 00 | 3.04 | 1.52 |
| 0 | 3.20 | 1.60 |
| 1 | 3.35 | 1.67 |
| 2 | 4.06 | 2.03 |
| 3 | 4.77 | 2.38 |
| 4 | 5.48 | 2.74 |
| 5 | 6.19 | 3.09 |
| 6 | 6.60 | 3.30 |
| 7 | 7.62 | 3.81 |
| 8 | 8.33 | 4.16 |
| 9 | 9.04 | 4.52 |
| 10 | 9.75 | 4.87 |
| 11 | 10.46 | 5.23 |
| 12 | 11.16 | 5.58 |
| 13 | 11.88 | 5.94 |
| 14 | 12.58 | 6.29 |
| 15 | 13.30 | 6.65 |
| 16 | 14.02 | 7.01 |
| 17 | 14.73 | 7.36 |
| 18 | 15.44 | 7.72 |
| 19 | 16.14 | 8.07 |
| 20 | 16.86 | 8.43 |
| 21 | 17.56 | 8.78 |
| 22 | 18.28 | 9.14 |
| 23 | 18.98 | 9.49 |
| 24 | 19.71 | 9.85 |
| 26 | 21.33 | 10.56 |
| 28 | 22.55 | 11.27 |
| 30 | 23.97 | 11.98 |
| 32 | 25.40 | 12.70 |
Length
| Length (Inches) | Length (mm) |
| ¼” | 6.4mm |
| ⅜” | 9.5mm |
| ½” | 12.8mm |
| ⅝” | 15.9mm |
| ¾” | 19.1mm |
| ⅞” | 22.2mm |
| 1″ | 25.4mm |
| 1 ¼” | 31.8mm |
| 1 ½” | 38.1mm |
| 1 ¾” | 44.5mm |
| 2″ | 50.8mm |
| 2 ¼” | 57.2mm |
| 2 ½” | 63.5mm |
| 2 ¾” | 69.9mm |
| 3″ | 76.2mm |
| 3 ¼” | 82.6mm |
| 3 ½” | 88.9mm |
| 4″ | 101.6mm |
| 4 ½” | 114.3mm |
| 5″ | 127.0mm |
| 6″ | 152.4mm |
Sizing explained
If you search for sizing, you will see different lengths, gauges, and threads, confusing several people. Take extra care while choosing because one wrong choice may ruin the entire application. Here are three parts worth keeping in mind.
The main measurements fall under three categories – threads per inch (TPI), length, and gauge. These are the measurements you will often encounter when shopping for these items.
Gauge
The gauge is the first number, referring to the thread diameter. Others also refer to it as major diameter. The size labels #0 to #14 have a major diameter of less than 0.25 inches, while greater than #14 are in fractions of an inch.
Each gauge size has an equivalent decimal value. For example, a #1 gauge is 0.073 inches. The size has an incremental value of 0.013 inches per gauge.
Aside from the major diameter, we also have the minor. It refers to the width measurement below the threaded part. We call the unthreaded portion the shank diameter.
Length
The length of the shaft is the next important measurement. The part of it that drives through a surface is the shaft length. You measure from the tip to the top of the head for types that can drive beneath the surface. These countersinking types include the bugle-head, trim-head, and flat-head.
You measure from the head’s bottom to the tip for types you cannot drive beneath the surface. Some examples of this non-countersinking are round, hex, button, pan, and truss. One exception to it is the oval head, which classifies as partial-countersinking.
Threads per Inch (TPI)
The TPI refers to the thread count within a one-inch section. It occasionally follows the gauge with a hyphen. A label that says #8-10 means a #8 gauge and ten threads per inch.
Length
Several lengths are available in the market. The largest size most manufacturers produce is size 32. It has a shank diameter of 0.5 inches and a head diameter of one inch. On the other hand, the small size most manufacturers have is size 0000, with a shank diameter of 0.054 inches and a head diameter of 0.108 inches.
Generally, a head reduction of 0.0028 inches and a shank reduction of 0.0014 inches happens until it reaches size one. The diameter reduction is 0.006 inches and 0.003 inches after it passes this point, respectively.
By Head Drive Type
The main head types are as follows.
- Slot-head – This is the most common variety among all the head types. You can use a flat-head screwdriver to turn the head through the material.
- Robertson or Square Drive – The Robertson has a few advantages over the Phillips. The square drive features a square head, reducing the chances of slippage. You will usually find it in pocket screws.
- Phillips – The Phillips is more functional than the slot-head variety. It works well on different wooden materials, allowing you to insert it with minimal risks. You may encounter slipping when driving it through the final section.
- Starhead – There has been an increase in popularity for star-head over the last few years. It is popular among woodworking applications because of its reliability. It can also accommodate more torque.
