How to Manufacture an Angle Iron Fence Structure for 358 Prison Mesh Fencing

How to Manufacture an Angle Iron Fence Structure for 358 Prison Mesh Fencing

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When it comes to high-security fencing, 358 prison mesh fence or 358 welded mesh panels, as they are also known, is one of the top choices. It’s hard to climb, hard to cut, rigid and a great barrier and deterrent.

If you’re planning to install a 358 prison mesh fence system at your site, you might want to consider a fence structure comprising of angle iron posts and flat cover strips. This system allows you to “sandwich” and clamp adjacent fence panels securely, lends itself to stepping panels where necessary, and offers many other benefits.

What Kind of Welded Mesh Panels Can You Use This Type of Structure With?

Like every fence structure design, an angle iron and flat bar cover strip system is not a one size fits all solution. However, if you are installing 358 welded mesh panels that are flat and do not have horizontal bends, or another type of welded mesh panels that might have bends but has larger apertures, this system will work well.

Why Does Angle Iron Work Well for Fence Structures?

If angle iron posts seem like a strange choice, you might be more used to tubular fence posts or even I-beam-style fence posts. However, there are several reasons why angle iron fence structures work well, including:

  • Angle iron is a structural steel profile, so it’s very strong relative to the weight per foot or meter of the steel; this is ideal for high-security welded mesh panels, which are very heavy
  • Angle iron is available in a wide variety of sizes, so you can design a fence structure that is suited to the specific panel size and type you’re using
  • When you’re punching or drilling holes in the steel, you only have to go through one side of the angle
  • Angle iron does not trap water, so it won’t be subjected to the freezing problems faced by tubular posts in cold climates

When installed with one face of the angle facing forward, your fence will look no different to a fence with square posts. However, you get all of these benefits at the same time.

What Goes Into an Angle Iron Structure for 358 Welded Mesh Fencing?

Now that you know what you can use an angle iron fence structure for and why it’s a good idea, the next thing we need to cover is how to design and manufacture this type of fence. So let’s look at some of the more important components of this type of high-security fence structure.

Angle Iron Posts

The first component you will need for an angle iron 358 welded mesh fencing structure is the posts, which in this case, are manufactured from angle iron.

Usually, these are made from a heavier-duty angle iron with dimensions in the region of about 70 x 70 x 6mm, although you can also choose an unequal angle if that works better for your design.

Since you will need to have holes drilled and punched in the angle iron post to attach top and bottom rails and the flat bar cover strip, you will need to choose something that is wide enough to accommodate those.

Generally, it’s a better idea, when designing your angle iron posts, to choose punched, slotted holes that are longer than they are wide so that there is some play available when installing the fence system. This will usually give you around 20mm of lateral or vertical movement, depending on which way the slotted holes are oriented.

Usually, holes for top and bottom rails will be horizontal slots and holes for panel attachment will be vertical slots.

Top and Bottom Angle Iron Rails

358 welded mesh panels are very heavy, which is one of the reasons why you might want to consider angle iron top and bottom rails. The other is that using these rails allows you to construct the fence in post and rail sequence, so you are always sure that your posts are correctly positioned. Essentially, this allows you to use the top and bottom rails as a permanent spacing jig for your fence.

Top and bottom rails are drilled so that panels can be bolted in place, and top rails sometimes feature an optional serrated comb for added security.

Typically, top and bottom angle iron rails for 358 welded wire mesh fencing are smaller, usually 40 x 40 x 5mm angle or similar.

In order to facilitate bolting of top and bottom rails to angle iron posts, they are usually notched on one side to allow a flush and tight fit.

Flat Bar Cover Strips

Angle iron post sandwitch diagram
The final part of your angle iron 358 prison mesh fence structure is the flat bar cover strip. These strips are designed to sandwich panels in place.

As you can see in the diagram on the right, one flat bar cover strip will hold two adjacent panels in place by sandwiching them together before bolting.

Holes on flat bar cover strips should line up with the slotted holes on your angle iron post and can be a single line or a double line for a little more lateral movement allowance if necessary.

General Design Tips and Ideas for 358 Prison Mesh Fencing Angle Iron Structures

As you can see, there is a fair amount of design flexibility available for angle iron fence structures for 358 prison mesh and welded mesh panel fence structures. There are a few other design considerations you will want to make before designing your fence.

Angle Iron Fence Structure Finishes

Ideally, when you are using an angle iron post and flat cover strip fence structure design for your welded mesh fence, you will have your posts hot dip galvanized after manufacturing. This will ensure that the structure is as corrosion-resistant as possible.

Unlike some other metal fence components, angle iron and flat bars tend to hold up well to the hot dip galvanizing process, and they rarely twist or warp because, as structural steel components, they are designed to be stronger profiles.

Angle iron fence structures for 358 prison mesh or high security welded mesh panels can also be painted or powder coated to match your panels if you are installing a coated panel. This helps to create an esthetically pleasing fence system.

Holes and Hardware

Like any fence, the hardware you choose for your angle iron structure welded mesh fence system is probably going to be the weakest part of the fence – and the one most likely to be targeted by anyone hoping to get through the fence.

As we’ve already mentioned, slotted holes in posts allow for some lateral or vertical movement if necessary, but it’s advisable to use ordinary round holes in flat cover strips. One good way to increase the security of this type of fence is to countersink the holes in the flat bar cover strip and then use a corresponding bolt. Choosing security bolts or screws for this purpose is another great idea so that the bolts can’t be removed with a simple screwdriver.

Shear-off nuts, also known as breakaway nuts, are another good choice to beef up the security of your fence hardware for this type of 358 mesh prison fence. These nuts have a hex head that breaks away when torqued, leaving only a smooth, hard-to-remove metal cone on the fence.


One way to beef up the security of any fence is to include fence top security like barbed wire, razor wire or electric fence.

As you can see in the main image in this article, this is easy to do with an angle iron fence structure, simply by extending the posts so that they project the desired length above the top of the fence. Then you can simply tie your wire, coils and other fence top security measures to the structure.

Design Sketch for Angle Iron 358 mesh Fence Structure

Now that we’ve described how an angle iron structure for a 358 mesh prison fence and other high-security welded mesh fence systems can be manufactured be sure to download our free design sketch below so that you can use this as the basis for your own design.

Download Angle Iron Structure for 358 Welded Mesh Design Sketch

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