04 May

What Are the Different Types of Screw?

We all love a good screw, but did you know there are a whopping 19 different types? Each one has been meticulously engineered for use with different materials and surfaces. Using the wrong one for your project could be a disaster. In other words, you’ll be screwed.

Find out which screw is right for your project by learning about all the different types. From eye lags to sex bolts, discover every screw in this month’s article.

Wood Screws

Wood screws are perhaps the most commonly recognised type of screw. They have a smooth shank and tapered point that make them ideal for penetrating wood.

What they’re used for: all types of wood.

Machine Screws

Blunt ended screws with threads, typically made from brass or steel.

What they’re used for: fastening metal parts together

Thread Cutting Machine Screws

They look similar to standard machine screws, but thread cutting machine screws are self-tapping screws that produce threads in existing holes in metal.

What they’re used for: most often used with wood and metal.

Sheet Metal Screws


Sheet metal crews are fully threads and pointed.

What they’re used for: sheet metal

Self Drilling Screws

A pointed screw with sharp cutting threads that tap the hole during installation.

What they’re used for: quick drilling into metal or wood.

Hex Bolts

Hex bolts have a flat hexagonal head and threads to be used with a nut or tapped hole.

What they’re used for: fastening wood to wood or metal to wood.

Carriage Bolts

Recognisable by their smooth rounded head and square neck. 

What they’re used for: fastening metal to metal or metal to wood.

Lag Bolts

Lag bolts have a hexagonal head with a wood thread and pointed tip. They are particularly tough fasteners.

What they’re used for: connecting heavy lumber or other heavy materials that are bearing an intense load.

Socket Screws

Commonly referred to as Allen Heads due to the fact that they are fastened with a hex Allen wrench, socket screws have a hexagonal internal drive built into the head.

What they’re used for: fasting machine parts.

Set Screws

Set screws are notable for their lack of head. The entire screw can be screwed into a threaded hole so that the entire screw is out of sight.

What they’re used for: to secure an object within another object.

Eye Bolts

Eye bolts have machine threads and a circular ring on the head end.

What they’re used for: attaching a rope, chain or cable.

Eye Lags

Eye lags look similar to eye bolts but have wood threads instead of machine threads.

What they’re used for: light duty applications in wood or lag anchor.


J-Bolts have a ‘J’ hook on the head end.

What they’re used for: as a fastener for construction projects.


A fastener in the shape of the letter U. U-Bolts have two threaded arms extending from a curved base.

What they’re used for: fastening pipes and as anchors for foundations and roofs.

Shoulder Bolts

Also known as stripper bolts, shoulder bolts have a round head and machine tip.

What they’re used for: rotating items such as bearings and bushings.

Elevator Bolts

Elevator bolts are easily recognisable by their large, flat head and long body.

What they’re used for: in conveyor belts, elevators and similar mechanical systems that raise things up and down.

Sex Bolts

A female threaded nut used in combination with mating screws.

What they’re used for:  bolting applications where a head is desired on both sides of the joint.

Mating Screws

A companion for sex screws. They have a plan shaft and a threaded portion, which is received by the internal threaded part of the sex screw.

What they’re used for:  bolting applications where a head is desired on both sides of the joint.

Hanger bolts:

Hanger bolts have wood thread on one end and machine thread on the other.

What they’re used for: suspending objects from or attaching items to wood.

We’ve got every type of screw available in stock, ready to deliver throughout London. We pride ourselves on our stock availability and wide selection of products. No matter whether you’re undertaking a large commercial project or building a small garden shed, we’ve got everything you need to get the job done. 

Contact us today to place an order.