If you’re building fences or foundations, knocking posts into the ground by hand is an arduous and lengthy process. Thankfully, post knockers exist to take the strain out of this difficult task. In this guide, we will explain how to correctly use a post knocker. Keep reading to learn more…
What is a post knocker?
First, what do we mean when we talk about post knockers? As the name suggests, post knockers, sometimes referred to as fence post pounders, or post rammers, are tools designed to drive a fence post into the ground.
They are incredibly useful because they drive the post into the ground using impact or force with ease and precision, without causing damage to the post, or the operator. They also use a lot less energy, proving to be a more efficient way to complete this job.
There are three main types of post drivers, which are: manual post knockers, petrol-powered post knockers, and mounted post knockers.
Manual post knockers
Manual post knockers offer a straightforward, cost-effective solution for planting posts. They are made up of a rudimentary steel tube, open at one end, with handles on either side. To use them, the operator positions the knocker over the tube, then drives the tube down onto the pole. The force applied drives the post into the ground with each impact.
Manual post knockers are the cheapest option, and are easy to use – but require physical effort to repeatedly hammer posts into the earth. They are a great option for labourers working on small-scale projects, especially in areas where heavy machinery would not be appropriate or usable.
Petrol engine post knockers
With a petrol-powered engine to assist, this type of post knocker is a more powerful and efficient alternative to manual options. The engine powers a high-impact internal hammer mechanism that drives in the fence posts within a matter of seconds.
Petrol post knockers use a versatile 2-stroke engine, which allows the unit to be left idling while new posts are set up – meaning the hassle of restarting the engine is a thing of the past.
The ease of use and speed of which posts can be erected make petrol engine post knockers a highly-desired power tool, although they will come in at a higher cost than manual knockers.
Mounted post knockers
As the name suggests, a mounted post knocker is an attachment that can be mounted onto a machine. Commonly used with tractors and excavators, this attachment leverages the power of the machine to drive posts quickly into the ground.
This superior level of power makes it possible to drive posts into hard or rough terrain with ease, and is the ideal tool for use on large scale fencing projects, such as in agricultural applications like fencing off a field.
The only major hurdle is that a heavy-duty vehicle is required, and the user must be competent with operating the machine to ensure posts are laid correctly.
Preparing to use a post knocker
Before you use your post knocker, it is important to properly prepare for the operation. The process of knocking in posts can be dangerous, regardless of which type of post knocker you use. Here is some general guidance to follow:
Familiarise yourself before use
The type of post knocker you use can have a big impact on how you use it. Take time to familiarise yourself with your post knocker. Where possible, read the manufacturer’s instructions on safe handling.
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If you are using a manual post knocker: before using this post knocker on-site, test how it feels to hold, and practise the motion of lifting it up and bringing it down until you feel comfortable – and can use the machine safely.
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If you have a petrol engine post knocker: ensure that you know how to correctly engage and disengage the engine before putting the machine to work. You should also make sure you are well-versed in how the post knocker will function before using it.
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If you have a mounted post knocker: before use, make sure that you have correctly attached your post knocker to your machinery, and run a test to ensure that it works as intended.
Measure and mark
Lay out the posts along your intended route in a uniform manner. Where possible, space the posts out evenly to reduce the strain on each when subjected to the elements. You may need to use stakes and a string line to mark where each post needs to go, and use a laser measure to ensure each post is equidistant.
During this process, check the ground of each post site, and clear away any debris, rocks, or other obstructions. This will prevent tripping hazards when laying the posts, and will ensure a stable surface for driving them in.
Before driving the posts in, ensure that there are no underground obstructions, such as water pipes or gas lines, which may be damaged. If you are unsure, contact your local utility services to mark these lines before you start work.
Safety gear
When using a post knocker, safety is paramount. The equipment used can cause harm to the operator, and others in the vicinity. Proper safety gear can help to protect against these potential hazards. You should always make use of the following pieces of equipment to maximise your safety:
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Wear protective gloves to protect your hands from blisters, splinters, and potential pinching.
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Protective goggles will shield your eyes from any debris that comes loose when driving posts into the ground. This is especially important when working in rocky or wooded areas.
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Steel-toe cap boots will protect your feet in the event that a post falls over or comes loose, or if the post knocker slips from its intended target.
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Ear protection is ideal when using a petrol engine, or mounted post knockers, which can be noisy, and lead to ear damage.
How to use a post knocker
With the ground checked, posts in place, and safety gear on, it is time to use the post knocker. Here are the steps you need to follow:
Position the post
Align the post in an upright position at the desired location. Use a spirit level or plumb line to ensure it is vertical. This step is important, because a lopsided fence will be less secure.
You may also want to prepare the soil to make the process of driving in the post easier. Dig a small hole using a shovel, or a post hole borer, to create a gap to slide the post into position.
Position the post knocker
With the post upright, position the post knocker directly over the post. Guide the post into the hollow end of the tube to keep it in the correct position.
Drive the post into the ground
The time has come to start driving the post into the ground. Below we’ve included general use instructions for each type of post knocker.
For manual post knockers
To use a manual post knocker, you will need to:
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Lift the knocker over the post.
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Drop it onto the post.
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Repeat until the desired depth is reached.
For petrol engine post knockers
To use a petrol engine post knocker, you will need to:
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Start the engine.
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Carefully apply downward pressure on the post knocker handles.
This will allow the knocker to use its internal mechanism to drive the post into the ground at a steady pace. -
Lift off when the post is fully secured in position.
For mounted post knockers
To use a mounted post knocker, you will need to:
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Use the cab lever connected to the attachment to drive the post into the ground.
Be careful with the force you apply, as the power of a tractor or excavator may be too much for a post, and can force them to break. -
Apply gentle pressure to ensure a steady insertion.
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Remove from the post once it has reached the desired depth.
Check the post halfway through
As you drive the post into the ground, check the post is still vertically aligned. If it has turned or leaned during the process, adjust as necessary. It is easier to do this when it is half inserted rather than fully buried, so make sure to stop halfway through and check.
You should also check for any cracks, splits, or other damage to the post, as these can shorten the lifespan, and therefore the integrity, of the post.
Follow the one-third rule
The one-third rule is a simple, yet vital rule of fencing. At least one third of your post should be buried underground to ensure it remains securely buried.
Following this rule negates the concern of trying to measure out lengths for differently-sized posts. Simply mark a line where the bottom third of the post ends, and ensure that you keep driving the post in until it reaches that point.
Rest then test
Once the post has been correctly driven into the ground, there are two things you will want to check.
The first is that the finished product is still vertical. Use a spirit level or plumb line to ensure it is level. If it is not, you will want to amend it now while the soil is still softened up from the recent impact.
For the second check, you want to ensure that the post is stable. While a slight check is fine at this point, we would recommend leaving the post to settle for a short while before properly checking it is secure. This is because the soil surrounding the post may have weakened from the impact, and can be further disturbed if the post is wobbled vigorously.
If you move the post around immediately, you could lead to posts becoming less stable in the ground. Instead, waiting for a few days allows the ground to firm up, giving you a truer test of a post's stability.
Looking for the best place to buy a post knocker?
If you’re looking for a post knocker, you’ll find them here at Hughie Willett Machinery.
We are specialists in agricultural, arboricultural, and ground care equipment. We sell new, used, and ex-lease equipment, and offer servicing and repair work to support you through the lifetime of your machinery.
If you would like to learn more, our friendly team of experts are knowledgeable about our products, and can give you the best advice on your new purchase. You can call us on 0121 308 1262 or send us a message using our contact form.
Browse our post knockers at Hughie Willett Machinery
For more information about ground care machinery and equipment buying guides and advice, explore the Hughie Willett Machinery blog…
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