Screws and Fixings
Different types of screws are used for doing several jobs. The job can be made easier by using the right type of screws and tools.
Screw Sizes:
A screw in basically specified by its type of head and slot, diameter and length. For example a wood screw is specified using two different numbers. The first number indicates its diameter. The larger number means a larger diameter. The next number gives its length. It does not include the head thickness.
Types of threads:
Screw are available with Metric, British Standard Whitworth and British Association types of threads.
Screw Materials:
Generally steel, brass and stainless steel are used for making screws. Often galvanizing is done on steel screws for corrosion resistance. Nickel or other decorative plating is also done. Selection of materials depends on the temperature, corrosion resistance, joint material, required strength and cost.
Common Types of Screw Heads:
The screws have different types of heads. Most commonly used types are:
Counter Sunk Slot Head: This type is generally used in woodworking. It can be easily tightened flush with the surface of the material.
Round head and Pan Head: These are used mostly for fixing different pieces of material together usually for decorative purposes.
Truss Head: They have a large head diameter and low height. They are used to cover bigger diameter clearance holes mostly in sheet metal.
Cheese head: They have a disc or cylindrical outer edges and height is approximately half of the head diameter.
Flange head: The flanged heads have different head styles as above with an additional flange at the head base. These can be used without a washer.
Screw Fixing:
There are several type screws used for of fixing different items. Drilling a pilot hole to insert the screw prevents it from binding.
Each variety of screws need a different driver design depending on the shape of the slot or the head. The most common types of screws need a starlight, Phillips,Robertson, hex or torx type of drive.
A hand screw driver is a common tool for fixing. You can use a power screwdriver or power drills with some driving bits for fixing the screws. It is critical that there is no excessive torque as that can damage the screw.
Types of Commonly Used Screws:
The screws have either a tapered or a straight shank. Tapered shank screws can be driven into a substrate directly or may need a pilot hole. Straight shank screws are generally machine screws. Most screws are tightened with a clockwise rotation and are known to have right-hand threads.
Screws with tapered shanks or self-threading screws:
Wood screw: It is a taper shanked metal screw used for fixing wood pieces together. Wood screws usually have countersunk heads. Screws with flat, oval or pan heads are also used.
Chipboard screw: These are like drywall screws with a thinner shaft and asymmetrical threads that provide a better grip.
Concrete screw/Masonry screws: These are made of carbon or stainless steel and are used for fastening metal, wood, or other materials into the concrete. A pilot hole is drilled into concrete to install them.
Deck Screws: These are like drywall screws with a larger diameter, auger threads and have corrosion resistance.
Hanger bolts: These are like wood screws and fixings, but both ends are pointed and threaded. These are used in hidden joints in woodworking.
Drywall Screw: They have a bugle head for attaching drywall to wood .
Coach/Lag Screw: It is like a wood screw with a larger length up to 15 in.
Mirror Screw: It is a flat-headed wood screw. There is a tapped hole on its top to fix a chrome-plated cover for decoration. It is used for installing mirrors.
Sheet Metal Screw: These have sharp threads to cut into the sheet metal, wood or plastic.
Machined Screws: They have straight shanks and are fitted into tapped holes or with nuts having mating threads.
Screw Sizes:
A screw in basically specified by its type of head and slot, diameter and length. For example a wood screw is specified using two different numbers. The first number indicates its diameter. The larger number means a larger diameter. The next number gives its length. It does not include the head thickness.
Types of threads:
Screw are available with Metric, British Standard Whitworth and British Association types of threads.
Screw Materials:
Generally steel, brass and stainless steel are used for making screws. Often galvanizing is done on steel screws for corrosion resistance. Nickel or other decorative plating is also done. Selection of materials depends on the temperature, corrosion resistance, joint material, required strength and cost.
Common Types of Screw Heads:
The screws have different types of heads. Most commonly used types are:
Counter Sunk Slot Head: This type is generally used in woodworking. It can be easily tightened flush with the surface of the material.
Round head and Pan Head: These are used mostly for fixing different pieces of material together usually for decorative purposes.
Truss Head: They have a large head diameter and low height. They are used to cover bigger diameter clearance holes mostly in sheet metal.
Cheese head: They have a disc or cylindrical outer edges and height is approximately half of the head diameter.
Flange head: The flanged heads have different head styles as above with an additional flange at the head base. These can be used without a washer.
Screw Fixing:
There are several type screws used for of fixing different items. Drilling a pilot hole to insert the screw prevents it from binding.
Each variety of screws need a different driver design depending on the shape of the slot or the head. The most common types of screws need a starlight, Phillips,Robertson, hex or torx type of drive.
A hand screw driver is a common tool for fixing. You can use a power screwdriver or power drills with some driving bits for fixing the screws. It is critical that there is no excessive torque as that can damage the screw.
Types of Commonly Used Screws:
The screws have either a tapered or a straight shank. Tapered shank screws can be driven into a substrate directly or may need a pilot hole. Straight shank screws are generally machine screws. Most screws are tightened with a clockwise rotation and are known to have right-hand threads.
Screws with tapered shanks or self-threading screws:
Wood screw: It is a taper shanked metal screw used for fixing wood pieces together. Wood screws usually have countersunk heads. Screws with flat, oval or pan heads are also used.
Chipboard screw: These are like drywall screws with a thinner shaft and asymmetrical threads that provide a better grip.
Concrete screw/Masonry screws: These are made of carbon or stainless steel and are used for fastening metal, wood, or other materials into the concrete. A pilot hole is drilled into concrete to install them.
Deck Screws: These are like drywall screws with a larger diameter, auger threads and have corrosion resistance.
Hanger bolts: These are like wood screws and fixings, but both ends are pointed and threaded. These are used in hidden joints in woodworking.
Drywall Screw: They have a bugle head for attaching drywall to wood .
Coach/Lag Screw: It is like a wood screw with a larger length up to 15 in.
Mirror Screw: It is a flat-headed wood screw. There is a tapped hole on its top to fix a chrome-plated cover for decoration. It is used for installing mirrors.
Sheet Metal Screw: These have sharp threads to cut into the sheet metal, wood or plastic.
Machined Screws: They have straight shanks and are fitted into tapped holes or with nuts having mating threads.
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