Traditionally, chainsaws are believed to be used for wooden objects only. But there is a special class of chainsaws that can be used to cut concrete and all kinds of rocks and stones. People who work in the construction industry or mining would be familiar with this type. In this blog, I shall answer some of the most common queries most beginners and professionals have about concrete chainsaws.
Concrete chainsaws are a robust version of traditional saws that use a diamond-coated chain cooled with water. They can be used to cut different types of concrete, bricks, masonry items, rocks, and even steel pipes/bars. Ensure that you turn on the water supply. Draw an initial outline on the concrete and score the outline with an initial cut of a few inches’ depths. Then cut out the entire outline by plunging the guide bar through the opposite surface of the concrete.
The short answer gives you a surface-level understanding of these saws. In this blog post, I will explain in more detail how concrete chainsaws work and how they should be used.
- 1 What is a Concrete Chainsaw?
- 2 Can a Chainsaw Cut Concrete?
- 3 How Fast Does a Concrete Chainsaw cut?
- 4 How does a Concrete Chainsaw Work?
- 5 How deep can you cut concrete?
What is a Concrete Chainsaw?
A concrete chainsaw utilizes a powered chain for cutting concrete, bricks, tiles, and other masonry items. The chain’s cutting blades contain diamond grit which imparts extraordinary strength and endurance for action on tough surfaces.
Compared with regular wood-cutting chainsaws, concrete chainsaws use a much stronger and harder cutting chain to cut tough surfaces. The chain’s cutter teeth are laser welded with diamond segments which increase their hardness and endurance.
● How are they different from regular chainsaws?
There are two major differences between normal chainsaws and those that can cut concrete. The first is the chain material. Regular chainsaws use cutter blades made up of stainless steel, while concrete saws have diamond-coated blades. The second major difference is that concrete chainsaws have a pressurized water circulation instead of bar and chain oil in regular chainsaws.
The water helps to dissipate a large amount of heat produced due to the chain’s grinding action. Furthermore, it helps to wash away the dirt produced in the process. You should know that dust produced by grinding stone, marble, and rock is composed of crystalline silica particles. Exposure to these particles raises the risk of lung cancer and other breathing problems. To lower this dust formation, you should always turn on the water cooling.
Another very interesting feature of concrete chainsaws is that they are free of any kickbacks during operation. Regular chainsaws operate on wood which is a fibrous material due to which the chain often gets snagged in it. Whereas concrete is a non-fibrous, brittle structure, the chain doesn’t get caught in it, thereby reducing any kickback risk. Nevertheless, I still recommend wearing full protective gear while using concrete chainsaws.
● Where are these chainsaws used?
Concrete chainsaws find applications in the construction industry, demolition jobs, firefighting, and mining works. The thin guide bar coupled with the diamond-coated chain provides better precision and less material wastage. They are used to cut out sections in brick walls in firefighting emergencies. In addition, they can cut out certain small rocks while digging in mines or even while sculpting a statue. Compared to circular saws, their thin guide bars can make precise cuts with less over-cutting, which is accurate 90-degree edges.
Can a Chainsaw Cut Concrete?
A normal chainsaw can not cut concrete. But a specialized chainsaw with a diamond-coated chain material can cut through concrete. They can also be used to cut marble and all kinds of rocks and other stones.
Traditional chainsaws use a steel chain to cut through wood. The chain is lubricated with chain oil to ensure its longevity and performance. Concrete chainsaws use a pressurized water flow to achieve both cooling and dust control.
The harder the material that you want to cut, the harder the cutting tool needs to be. It needs to have a greater hardness than the material you are working on. The Mohs hardness scale makes a relative comparison between the hardness of various minerals. The scale ranges from 0-10, with 0 being the softest and 10 being the hardest material.
According to the Mohs scale, diamond stands at 10, thus having the maximum hardness amongst all the materials. In comparison to diamond, the Mohs hardness for ordinary steel falls between 4 and 4.5. While that of concrete stands between 6 and 7.
Looking at the hardness scale, it is clear that a regular steel chain would not suffice to cut concrete instead of the chain cutting the concrete. The concrete wears out the chain quickly, and it can be thrown away. A diamond-coated chain with the maximum hardness value is the solution for this. It can work on any type of concrete surface. Not only that, the diamond coating enables the chain to work on various other types of minerals such as coal, gypsum, quartz, etc.
How Fast Does a Concrete Chainsaw cut?
Generally, you can expect that a chainsaw can cut through concrete 1 foot x 6 inches deep in 2 to 3 minutes, without steel rebar. But the cutting speed of a concrete chainsaw depends on various factors. These include the concrete composition, amount of steel rebar, the chain’s overall quality, and the power of the chainsaw.
1. Aggregate type:
Aggregate is an essential concrete ingredient that imparts durability, hardness, and texture to the concrete surface. Typically, concrete is a mixture of three main components, i.e., cement, water, and aggregate. Examples of aggregate materials include sand, gravel, limestone.
When a hard aggregate material is used, it increases the time required to cut a unit length of concrete. The most usual example is quartz. Likewise, using a soft aggregate material like limestone makes it easier and faster for the chainsaw to cut concrete.
The size of the aggregate particle (also known as pitch) plays a vital role. It would be extremely difficult to cut a coarse specimen with over 1.5-inch gravel pitch. Whereas cutting more fine concrete with about 0.2-inch crushed gravel fragments is a much easier job.
Rebar consists of reinforced steel rods that provide tensile strength to the concrete structure. It becomes a bit tricky even for a professional to cut a concrete core with rebar. Not only does this affect the chain’s life, but it also adds to the additional working hours. It has been found that a 1% increase in steel content in a concrete core raises the cutting costs by about 2.5$/ft of concrete.
As a tip, always use low speed while cutting down steel. This may be time-consuming but would be easier for your cutting bits. Also, ensure that the water supply is kept a bit down too. Too much water coupled with high speed and heat could wear away the dry welds of the diamond segments.
How does a Concrete Chainsaw Work?
A concrete chainsaw works similarly to a regular chainsaw. It only uses a special diamond hardened chain, and instead of chain oil, water to cool the chain. It means you need a suitable water supply to use it.
Wielding a concrete chainsaw isn’t as straightforward as traditional wooden chainsaws. Let’s first look at the recommended steps that you should follow while using a concrete chainsaw:
● Step 1. Pre-Requisites:
Before starting with the job, there are some preparations you need to do:
- Check the fuel tank: Before using the chainsaw, ensure that the engine is in optimal working condition and the fuel tank is topped up.
- Examine the chain tension: Ensure that the chain tension is sufficient. The diamond chain must not sag unnecessarily down the guide bar. Nor should it be tightened to the extent that it is difficult to move it manually.
- Check the safety features: Check if all the chains saw safety features are in working well. This includes the chain brake, the mud flap, and the slurry baffle. These mechanisms are there to direct the muddy water away from the engine while cutting.
- Water supply: Water supply is critical to ensure the chain stays in working condition. Ensure the water delivered has a pressure of at least 20psi and a minimum flow rate of 4 liters/min.
- Remove obstructions: Clear away all the obstructions from the concrete to be sawed. These may include electrical connections, plumbing lines, or ducts.
- Wear safety gear: While using chainsaws, always wear PPE that should include a proper helmet with face-shield and earmuffs, gloves, steel-toed shoes, and chainsaw chaps for leg protection.
● Step 2. Plan the Cut:
- Outline: Before cutting, draw an online on the concrete block using a marker. This acts as a visual guide while cutting.
- Mark with the initial cut: Score the outline by plunging the guide bar about 1.5 inches deep into the concrete. Don’t cut through at this point. Rather make an initial cut (1.5 inches deep) along the outline. This helps in achieving a nice, straight finish. Always remember starting the cut from the bottom, then the top, and finally the sides.
● Step 3. Finish the Cut:
After scoring it initially, now use the plunge cutting method to cut out the marked section. This is done by plunging the guide bar through the cut-out at full throttle till it reaches the opposite surface. Plunge cut it throughout the outline until straight edges have been obtained and the cut-out has been removed.
It is important to apply a suitable feed force while plunge cutting. Make sure the feed force isn’t too high to drop the RPMs considerably. Once cut, handle the concrete block with caution. It is quite heavy and can injure a person if not dealt with carefully.
Will a concrete chainsaw cut rock?
A concrete chainsaw equipped with a diamond chain can cut all types of rocks, masonry items, bricks, and concrete.
Always consult the Mohs hardness scale to check if a concrete chainsaw would be useful against a specific material. The scale ranges from 0 to 10, with 10 being the hardness of diamond. This scale can help you compare the relative hardness of minerals and whether they can be conveniently cut with a diamond chain.
Will a concrete chainsaw cut rebar?
A concrete chainsaw can cut rebar, but it will shorten the diamond chain’s life. Rock the chainsaw up and down to cut rebar and concrete simultaneously. Use the wall walker as a pivot.
Cutting rebar with a diamond chainsaw isn’t as simple as cutting rock. Usually, straight plunge cutting isn’t an effective method in cutting down those steel rods as they are ductile. Make sure you always rock the chainsaw up and down to cut both the rebar and concrete simultaneously. A wall walker fulcrum is provided for this purpose. The fulcrum can be pressed against the wall and on rotating the handle up and down. This way, you can achieve a 4 to 1 mechanical advantage. This makes it a lot easier to cut the rebar.
How deep can you cut concrete?
The depth to cut concrete with a saw depends on the user’s expertise. Most beginners can cut through slabs that are less than 6-inches thick. If you are more experienced, you can cut through 12 to 14 inches of concrete. The maximum depth depends mainly on the bar length.
As the concrete becomes deeper than 6-inches, it becomes more challenging to handle the chainsaw as it tends to vibrate more. Most concrete walls are thick, so a beginner-level saw user can cut them if he uses the chainsaw properly and knows the correct technique. The typical length of a guide bar is 14-inches which defines the upper limit for the concrete that can be cut.