What Is the M5 Screw? Read This First!

By Rachel Lee
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The versatility of screws makes them a favorite component for DIYers and professionals. You do not need to carry an additional element like a nut to use these joining components.

If you are active in fixing things, an M5 screw is a common-turned product you would have come across. This screw is a mechanical fastener with a 5 mm thread diameter and a full threaded body.

In the US, turned products or fasteners have a vital role in driving the economy. The fastener revenue is expected to reach a staggering amount of around $ 11 billion by 2024.

Metric screws have become an active item of usage in almost everyone’s life – from fixing bicycles to home appliances. Hence, it is crucial to understand its basics as such info proves helpful during manufacturing or repair work.

Screws and Bolts: The Difference

Before understanding the M5 screw terminology, it is vital to familiarize yourself with the basics.

If you do not belong to the engineering domain, it is easy to confuse these three fasteners.

  • Screws
  • Nuts
  • Bolts

In a nutshell, both screws and bolts have external threads. On the other hand, a nut has a threaded hole that mates with the bolt threads.

So, a nut and bolt are a fastening pair used to join two different parts. Screws do not need a nut. They have threads all over the shank, enabling them to create their threads during installation.  

If you are an avid biker, you must have observed M5 bolts or screws joining different parts together. Most bikes have allen bolts or the following types of screws.

  • M4
  • M5
  • M6

M5 Screw Terminology

Metric screws, like other fasteners, are used to secure multiple components. An M5 screw has threads that are primarily triangle-shaped.

However, you can buy metric screws of the following thread shapes.

  • Trapezoid
  • Square

Since metric fasteners like M5 join mating parts, they need a clearance hole. This hole diameter needs to be 10% greater than the screw.

Here is an example of a typical M5 screw or bolt.

M5 – 0.8 – 15

When you read such a description, the meaning of each terminology is well defined.

  • M: Metric thread
  • 5: Nominal diameter (in mm)
  • 0.8: Pitch (in mm)
  • 15: Length (in mm)

Metric screws or fasteners are defined with respect to the pitch. A pitch is a distance between two consecutive threads.

This distance is measured along the fastener length. In the case of M5 screws, you can even come across a 0.5 mm pitch variant. The head diameter of typical M5 screws is 8.5 mm.

M5 Clearance Hole

The nominal diameter of an M5 fastener does not change like its pitch. Hence, the clearance hole calculations are standard.

A clearance hole is precise enough to let the screw or bolt find its way for fastening the mating parts. The hole should not be too small for the screw to cease rotating.

Hence, the calculation takes 10% clearance into consideration.

M5 clearance hole = (10% of nominal thread diameter) + (nominal diameter)  

                                  = 0.5 + 5

                                  = 5.5 mm

As a general rule, you should always drill a clearance hole using fully-threaded screws. If you buy a partially threaded M5 screw, a pilot hole is sufficient for the guiding process.

How to Drill an M5 Clearance Hole

You can drill an M5 clearance hole in four simple steps.

  • Pilot hole: Drill a small pilot hole less than the diameter of the M5 thread.
  • Drive screw: Take the M5 screw and drive it all the way down through the top part.
  • Screw backing: Using a power drill, back the M5 screw out of the material.
  • Insert again: Drive the screw again in the hole, clamping the two parts.

So, you can join any desired materials with a simple pilot and clearance hole. If you need to join soft parts with an M5 screw, the threads can create their holes.

In such a case, you do not need to drill a hole. Hence, versatility is a big advantage of an M5 screw.

Common Screw Types

Screws are perfect for DIY projects. They also serve as crucial elements for wood, drywall, concrete, and metal applications.

Usually self-tapping, you can use these fasteners without needing a clearance hole in most cases. Still, you can simplify the need for such an arrangement depending on the type.

  • Wood screws: These screws have a small shank on the length
  • Sheet metal screws: They have tapered sharp points and threads on the entire length
  • Socket screws: These screws have an Allen drive and smooth shank for longer lengths
  • Machine screws: Also known as stove bolts, they are fully threaded and can be used in tapped holes

Hence, the end applications play a vital role in screw-type selection. Importantly, M5 screws are available in almost every type.

Most DIYers use screws for bicycle or home improvement applications. For this purpose, you need to select the suitable type.

For instance, bicycle screws are generally galvanized or zinc-plated. Also, it makes sense to purchase stainless steel screws in case your bike needs proper replacement.

M5 Screw Applications

An M5 screw finds common utility in the following applications.

  • Bicycles
  • Home Improvement
  • Appliances
  • Electronic devices
  • Vehicles
  • Tools
  • Industrial machinery

Bike Maintenance – A Routine Application

If you observe almost all bicycle models, the M5 x 0.8 screws find extensive utility in joining parts as follows.

  • Fenders
  • Water bottle cages
  • Racks
  • Handles

However, depending on the application, the base material of these screws or bolts can vary. You can thus replace existing ones with uniform screws made of stainless steel.

This material is rustproof and offers better stability to the bicycle.

Moreover, this screw is applicable for various uses, ranging from wood to metal and plastic.

Related Questions

How Do You Cut a Machine Screw?

Cutting screws is necessary to reduce the shaft length. The best way to go about this process is by using a crimp tool or electrical plier.

You can also use a hacksaw blade to cut a machine screw. However, you can end up damaging the external threads.

What Is Meant by Screw Clearance?

Screw clearance is the space fabricated to allow a screw to pass through the materials without damaging the threads.

Generally, this clearance is in the form of a hole and calculated by adding 10% of the thread diameter.

What Does UNC Stand For?

UNC is a standard abbreviation for Unified National Coarse Thread. On the other hand, UNF stands for Unified National Fine Thread.

The UNC is compared with the ISO metric thread. It symbolizes the thread classification for standard threads.

How Do You Calculate the Length of a Screw?

You can measure the length of a screw as the distance between the end tip to the flat part of the head.

Usually, screws are flat on the bottom portion of the head. However, you can reduce the length by cutting if required.

See Also:
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What Bike Gear to Use on Flat Road
Jagwire Vs. Shimano Cables – Which One Is Better For Your Bike?
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