What does a #8 screw mean?

Asked By: Loree Aldehoff | Last Updated: 10th March, 2020
Category: hobbies and interests woodworking
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Their size is described as diameter, number of threads per inch (if used with a nut or in a threaded hole), and length in inches. In all cases, the larger the number, the larger the size. Consequently a #8 screw is larger than a #4 screw, just as a 3 inch bolt is larger than a 2 inch bolt.

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Also asked, what size is a #8 screw?

A #8 screw size is . 164 fraction of an inch. The diameters listed in the chart below are in fractions of an inch, so the #12 is just shy of 1/4 inch.

Additionally, how can you tell screw size? How to Determine Screw Size & Thread Count

  1. Lay the screw down on a flat surface.
  2. Place a steel rule down the axis of the screw.
  3. Count the number of thread gaps within 1 inch of the screw.
  4. Divide the count of thread gaps into the length.
  5. Place the screw on a flat surface.
  6. Lay a steel rule between two screw threads and measure across the diameter.

In this regard, what does the screw number mean?

What do the numbers - such as 8-32 mean on a machine screw? The first number is the diameter. The bigger the number the bigger the screw. The second number is the number of threads per inch.

Is a #8 or #10 screw bigger?

Machine screws are often found in sizes of: 0, 1, 2, 3, 4, 5, 6, 8, 10, 12, 14—the larger the number, the larger the screw.

28 Related Question Answers Found

What size hole do you drill for a #8 screw?

Wood Screw Pilot Hole Sizes
Screw Size Hard Wood
Tapered Bit Straight Bit
#7 5/32" 7/64"
#8 11/64" 1/8"
#9 3/16" 9/64"

How many MM is a #8 screw?

Diameter/Decimal/Metric Chart for Small Diameter Fasteners
Gauge or Diameter Decimal (in) mm
No.4 0.112 2.845
No.5 0.125 3.175
No.6 0.138 3.505
No.8 0.164 4.166

Should I use #6 or #8 drywall screws?

Gauge refers to the diameter of the drywall screw. In most cases, you will be using either #6 or #8 drywall screws. Keep in mind that as gauge numbers increase, the screw becomes larger in diameter. So, a #6 drywall screw would be thinner than a #8 drywall screw.

What is a size 10 screw?

the way the head diameter was worked out was to half the number, in this case 8=4 and add 1=5 and then call the result as sixteenths of an inch,so a 8 screw head was 5/16 in diameter and a number 10 screw head was 3/8" diameter ( 10 divided by 2 = 5 and add 1 =6 and call it sixteenths which = 3/8".

What size is an 8 32 screw?


Tap and Clearance Drill Sizes
Screw O.D. Free Fit
6-32 0.1380 25
8-32 0.1640 16
10-24 0.190 7 (13/64)
10-32 0.1900 7 (13/64)

What size is a number 8 drill bit?

Drill sizes to 1" diameter
Drill sizes to 1" diameter Legend Fractional Inch Letter Drill Millimeters Number Drill
Millimeters Inches Designation
5.0546mm .199" # 8
5.1054mm .201" # 7
5.1594mm .203125" 13/64"

What is 8 gauge screw in MM?

Metric Imperial Screw Conversion Chart
Diameter (mm) Length (mm) Closest Imperial Size Gauge x Length
4mm 12 8 x 1/2
16 8 x 5/8
20 8 x 3/4
25 8 x 1

What is a #6 screw?

Screws have three basic measurements: gauge, threads per inch, and shaft length in inches. This means it's a #6 diameter, with 32 threads per inch (almost double the normal thread count as a standard wood screw) and an inch and a half long.

How do you measure a drill bit for a screw?

Wood Screw Diameter:
Hold the shaft of the drill bit up in front of the screw. You should only be able to see the threads of the screw (and maybe a bit of the screw). If you can't see the threads the drill bit is too big. If you can see too much of the screw, the bit is too small.

What do numbers on a drill mean?


When the drill is used as a screwdriver, the numbers indicate the torque breaking point. Higher numbers mean more torque. This feature is useful because you can limit the amount of torque that is applied to prevent screws, or the materials they are inserted in, from being stripped.

What size drill bit to pre drill for a #10 screw?

Drill bit sizes for pre-drilling (most commonly used sizes in bold)
Screw Size Pilot hole size for hardwoods* Pilot hole size for softwood**
#9 1/8 3/32
#10 1/8 7/64
#11 5/32 9/64
#12 9/64 1/8

What is a 10 24 screw?

When referring to screws, 10-24 is one description of the type of screw you are dealing with. More formally, 10-24 tells us the size and also the pitch diameter of the screw. Taken together, these numbers give us the definition of the screw.

What are standard screw sizes?

U.S. standard numbering systems list diameter sizes 0, 1, 2 ,3, 4, 5, 6, 7, 8, 9, 10, 12, 14 and 16, and fractional sizes from 1/4" to 2" in 1/16" increments, followed by a dash and the threads per inch (from about 6 to 80), and the length.

What Is A 2 56 screw?

The second number (80, 72, 64, 56, 32, 20, etc.) specifies the number of threads over a distance of 1" (25.4mm). So using the above information, a standard thread size of 2-56 has a major diameter of: 0.086" (2 x 0.013 + 0.060)

How do I choose the right size drill bit for a screw?


Use a bit 1/64” smaller than the target hole size for softwoods. Use a bit exactly the same size as the hole when working on other materials. If you're not sure which to select, choose a drill bit 1/64” larger than the hole you wish to create. This will account for variables such a wood density and screw type.

How big is a #4 screw?

US Machine Screw Diameters
Size Thread Diameter
Decimal Nearest Fractional
#4 0.11" 7/64"
#5 0.12" 1/8"
#6 0.13" 9/64"

How do you know what size drill bit to use?

Hold the shaft of the drill bit up in front of the screw. You should only be able to see the threads of the screw (and maybe a bit of the screw). If you can't see the threads the drill bit is too big. If you can see too much of the screw, the bit is too small.