4mm or 6mm Diameter Borescope: Which is Better?

by | Jan 15, 2021 | News

Before the advent of modern technology, mechanics and technicians would conduct inspections using a torch and mirror. This process was incredibly tedious and often produced poor results. However, there was no other way to look for defects inside confined spaces at the time.

Such inspections have been made much easier thanks to the invention of borescopes. These specialized devices are used to perform inspections within confined spaces that mechanics and technicians would have difficulty accessing.

Types of Borescopes

Borescopes come in many different varieties. There are borescopes that are made specifically for hazardous environments. Other borescopes may offer features such as waterproofing or water resistance. However, many of these borescopes are sub-categorized based on their size.

Borescopes come in 3mm, 4mm, 6mm, and 8mm sizes. These sizes refer to the diameter of the probe itself. Each of these varieties are used for different purposes. However the 4mm and 6mm varieties are the most popular.

What Is Better: A 4mm or a 6mm Borescope?

If you are interested in purchasing or renting a borescope for the first time, you should determine which size you need. Both 4mm and 6mm varieties offer their own advantages. Let’s take a closer look at each one and determine which is right for you.

4mm Borescopes

As their name implies, 4mm borescopes feature probes with a 4mm diameter. However, these probe sizes may vary between 3.7mm and 4.5mm. This means you can use a 4mm borescope to inspect confined spaces such as pipes that are wider than 4.5mm.

Most 4mm borescopes feature probes that are 1.5 meters in length. Some of these models may feature articulation, while others may not. They often have a working length up to 3 meters.

4mm borescopes are used in numerous different applications. Their small size means they can be used to inspect incredibly tight spaces such as diesel engines. They are also used for inspections in the casting and manufacturing industries.

The addition of articulation capabilities also enables them to easily maneuver around bends and corners.

6mm Borescope

6mm borescopes feature probes that are 6mm in diameter. They may vary between 5.1mm and 6.7mm in actual diameter, but are still useful for many purposes.

As with 4mm borescopes, 6mm varieties are used to perform borescope inspections in confined spaces. However, they may not be able to fit within the tight spaces that a 4mm probe can. 6mm probes may also include articulation features to get around bends and corners.

One special feature that 6mm probes possess more frequently than 4mm probes is a flexible metal braid along the probe length. This metal braid offers additional protection against any surfaces the probe comes into contact with.

Which Is Better?

It’s difficult to say whether a 4mm borescope is better than a 6mm borescope, or the other way around. This is because each one may be useful for a different purpose.

For example, you won’t be able to perform inspections for a 5mm pipe while using a 6mm borescope. However, you may be able to use a 4mm borescope to perform inspections of wider spaces that a 6mm borescope could also fit into.

So why not use a 4mm borescope for everything? The one potential drawback of using a 4mm probe is their fragility. All borescope probes tend to be fragile and should be handled with care. However, a probe may come into contact with the surfaces of the part it is inspecting.

A 4mm borescope may be more prone to damage due to the narrow size of its probe. By contrast, a 6mm probe may hold up better to wear and tear. The flexible metal braid found on some 6mm probes may also help protect them during inspections through winding paths.

Which Probe Is More Expensive?

Comparing the prices of 4mm probes against 6mm probes can be tricky as different manufacturers may have different price points for each of their models. However, we may be able to compare near-identical models from the same manufacturer.

The MCVS-2-4.5-1500 is a 4.5mm articulating videoscope that retails for $2495. A slightly different model MCVS-2-6-1000 is a 6mm articulating videoscope that retails for $1499. Both models have identical features and only differ in terms of probe diameter.

The 4.5mm variety costs around 40% more than the 6mm variety. For this reason, you should consider purchasing a 4mm probe only if you intend to perform inspections in spaces that are between 4mm and 6mm in size.

If you will be performing inspections for spaces that are larger than 6mm, you should go with the 6mm probe.

Things to Check Before Purchasing or Renting a Borescope

Choosing between a 4mm and 6mm borescope can be tricky. However, once you do make your choice, you should ensure you have purchased the right type of borescope. If you intend to use the borescope in hazardous or potentially explosive environments, you should go with one that is specially designed for these purposes.

Similarly, some borescopes are rated as waterproof. These are better suited for use in submerged applications than non-waterproof ones. Such characteristics may be more important than probe diameter for certain applications.

Where Can I Purchase 4mm or 6mm Borescopes

Borescopes should always be purchased from a reliable seller such as USA Borescopes. They offer a wide selection of 4mm borescopes as well as 6mm borescopes. If you are still unsure about the size of the borescope you require, you can reach out to their experts for more guidance on this matter.

Purchasing a borescope can be a large investment, so you should ensure that you are making the right decision. With the right applications and maintenance, your borescope should last for many years.