Kluje guide, different sizes of screws.
Screw sizes can be unfamiliar, confusing to anyone that is not familiar with them , but it really is pretty straightforward. Wood screws get their size from two different measurements. First, the diameter of the screw tells you the number of the screw, and the larger the number of the screw, the larger its diameter. That means a number 8 screw will be larger than a number six screw. The next measurement is the length of the screw. The length, it should be noted, is the length of the part of the screw that will be buried into the wood. For flat-headed screws, that pretty much is the length of the screw, but for raised or dome-headed screw, the length doesn't include the head of the screws. Typically, a screw will be named, for example, 10×3” screw. That means the diameter is the number ten, and the screw is three inches long.
There are different kinds of screws, and they each require differently shaped screwdrivers.
Slotted screws, which only have a single groove in the head, These are becoming less common as cross head screws are replacing them in almost every context. Cross head screws tend to be favoured because there are more points for screwdrivers to grip into, so the screwdrivers are less likely to slip out. Also, the points spread out the force of the screwdriver more, so the screw heads are less likely to get stripped. Cross head screws are mostly
Phillips screw, which looks like it has a plus sign with a wider space where the lines meet in the head.
Pozidriv screw. Like the Phillips screw, the Pozidriv screw has a ‘plus sign’ in the head, but it is slightly wider where the cross meets and has a second set of smaller crossed lines.
The table below allows you to convert screw sizes easily. It also tells you which kind of driver each screw will need.
Metric/Imperial Conversion Chart |
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Gauge mm | Length mm | Imperial Size | Gauge mm | Length mm | Imperial Size |
3 | 12 | 4 x 1/2 | 3.5 | 12 | 6 x 1/2 |
16 | 4 x 5/8 | 16 | 6 x 5/8 | ||
20 | 4 x 3/4 | 20 | 6 x 3/4 | ||
25 | 4 x 1 | 25 | 6 x 1 | ||
30 | 4 x 1 1/4 | 30 | 6 x 1 1/4 | ||
40 | 4 x 1 1/2 | 40 | 6 x 1 1/2 | ||
4 | 12 | 8 x 1/2 | 4.5 | 25 | 9 x 1 |
16 | 8 x 5/8 | 30 | 9 x 1 1/4 | ||
20 | 8 x 3/4 | 35 | 9 x 1 3/8 | ||
25 | 8 x 1 | 40 | 9 x 1 1/2 | ||
30 | 8 x 1 1/4 | 45 | 9 x 1 3/4 | ||
35 | 8 x 1 3/8 | 50 | 9 x 2 | ||
40 | 8 x 1 1/2 | 60 | 9 x 2 3/8 | ||
45 | 8 x 1 3/4 | 70 | 9 x 2 3/4 | ||
50 | 8 x 2 | 75 | 9 x 3 | ||
60 | 8 x 2 3/8 | ||||
5 | 25 | 10 x 1 | 6 | 30 | 12 x 1 1/4 |
30 | 10 x 1 1/4 | 40 | 12 x 1 1/2 | ||
35 | 10 x 1 3/8 | 50 | 12 x 2 | ||
40 | 10 x 1 1/2 | 60 | 12 x 2 3/8 | ||
45 | 10 x 1 3/4 | 70 | 12 x 2 3/4 | ||
50 | 10 x 2 | 75 | 12 x 3 | ||
60 | 10 x 2 3/8 | 80 | 12 x 3 1/4 | ||
70 | 10 x 2 3/4 | 90 | 12 x 3 1/2 | ||
75 | 10 x 3 | 100 | 12 x 4 | ||
80 | 10 x 3 1/4 | 110 | 12 x 4 3/8 | ||
90 | 10 x 3 1/2 | 130 | 12 x 5 1/8 | ||
100 | 10 x 4 | 150 | 12 x 6 |