The most common cuts you can make on a miter saw is 90° and 45° angular cuts. But an obtuse angle cut or a 135° cut can be quite tricky and confusing for most carpenters and DIY enthusiasts.
To do this, you will need to have some special tools or tricks to make an obtuse. In this article, I am going to talk about how to make a 135° or an obtuse angle on a miter saw.
What is an obtuse angle?
An obtuse angle is an angle that is greater than 90° but smaller than 180°. An example of a popular obtuse angle is a 135° cut. Unlike other angle cuts, an obtuse or 135° angle is a bit harder to cut.
It’s because the setting for this type of angle cannot be found by default in your miter saw. You need to manually adjust your miter saw to get this 135° cut. You need to have a distinct mathematical calculation to derive the exact setting which will help you cut the obtuse angle.
The benefits of using a miter saw other than other tools to cut obtuse angles?
The main advantage the miter saw has over another saw to obtuse angles is that its blade can be locked into a fixed position which allows you to get accurate cuts every single time.
So, suppose a straight cut can be achieved by locking the blade at a 90° angle, and all need to do is to get the blade down straight and you will get a straight cut. The same thing applies to other angles as well. You must move the blade at a marked setting on your miter saw and then lock it in place.
Then all you need to do is bring the blade down through the board. Due to the locking mechanism, the blade will always be stable, and you will get accurate angled cuts every time. Achieving this result consistent with other tools is almost impossible. (You may like this this article: best Miter saw stands review & guide.)
The math behind the 135° obtuse cut?
It is not just the tool that makes the cut, for an angle as complex as an obtuse angle, one needs to hit the mathematical accuracy as well to find the right measurements which will culminate into the desired final cut.
We must use the solution of the mathematical formula for the inside cuts and when we will join those inside cuts together, we will achieve the 135° angle. To derive the right measurement, we can use either of the following two formulas.
For a 135 ° cut the calculation will look something like this;
180 – angle = X
X/2 = the cut angle for the saw
The second formula:
Angle/2 = X
90-X = the cut angle for the saw
You can use either one of these formulas to derive the cut angle for your miter saw. Both will give you the same answer. Which formula you will use will totally depend on your preference. (Without using miter saw there are lost of way to make a 45 Degree Angle cut).
A step-by-step guide to cut 135° obtuse angle cut using a miter saw.
If you follow these steps step-by-step, then you will get a 135° obtuse cut. ( Before you start, change the miter saw blade for your desire right size.)
Step 1: Prepare the miter saw
When you are done with the calculations to find the perfect angle settings, you need to unlock the angle selection knob and set it to 22.5° which is the result found from the calculations performed earlier to achieve the 135° obtuse angle.
After setting the miter saw in that angle you need to lock it in place to make sure it doesn’t move away. After that, you need to set the tilt angle to 0°. The tilt angle of 0° means that cut will be straight and not a bevel cut.
Step 2: Setting up the wooden board
Smaller boards can be held in place with a clamp to hold it tightly against the fence and it stays there locked while making the cuts. In case of a longer board, you will need to use a clam to make sure it is held in place firmly.
Step 3: Time to make the cut
After securing the first piece of wood to the saw or the fence, its time cut inside the wood at a 22.5° angle. After making this cut you have to shift the saw blade on your right side. After making the cut on the first board we will take another piece of wood and make a cut across 22.5° on the right side.
Once both of the boards are cut according to the calculations, you will see that the boats will join perfectly.
Step 4: Measuring alignment
After cutting and joining the two boards, you need to measure using an appropriate a tool to see whether you have achieved the desired angle of 135° or not. It’s quite normal to have missed the perfect angle cut by a negligibly small margin. This small difference should not matter until the difference is quite big to ignore. (Check this article about: Best Miter Saw for Homeowner.)
What are the things that you should keep in mind while using the miter saw to get your desired obtuse angle?
- When working with a motor-powered tool as a miter saw, you must always wear protective clothing and goggles. This will protect you from serious injuries while working. It’s also recommended to wear a mask while using the miter saw. This will prevent you from inhaling the sawdust produced by the miter saw. Earmuffs will protect your ears from any potential damage.
- Always remember to keep your arms safe and at a safe distance while using the miter saw. If you keep your arms crossed while working increases the chance of an injury substantially.
- Remember to lock the blade and the knob after selecting the angle on the miter saw. Locking of the blade will ensure that the blade will not move during the process and ensure accurate cuts. Locking the blade will also reduce the chance of an unpredictable injury.
- Do not forget to clamp your blade tightly with a working fence, especially if you are using a longer board. If you clamp the tightly at the proper angle, it will ensure an accurate and clean cut every time. Not clamping the board tightly will reduce the chances of damage to the board.
The following task can be easily done by using a bisecting angle scale. If you don’t have the bisecting angle scale, we will show you a simple trick. First, take two similarly sized wooden blocks of the same width and length.
Then place a block tightly in opposition to the left wall and the other one on the right wall in the same way. After that, mark both untied parts with a sharp pencil. After that, create a straight line between those marks, and this will make your bisect angles. At last, cut them accordingly and use them in your work.
In order to make ideal miter cuts, use the marks tool to calculate the angles. For example, place the tool against the preferred wood block. Then identify the selected angle marked near the red indicator. After that, set the perfect measurement in your miter saw by looking at the marks tool. Cut your wood blocks following the size. Then join it perfectly in the desired angles.
Actually, you will find many reasons behind this problem. The most common problem of miter saw not cutting straight might be it gets bent, hurt, or sometimes the insecure installation occurs. In some cases, the miter bevel gauge might not be appropriately aligned in the saw. Even the unstable surface hinders making straight cuts
A miter saw is a fantastic tool to cut different types of angles for constructions and DIY projects. It’s really a lifesaver when it involves cutting complex angles, such as the bevel cut, acute angles, and obtuse angles.
With a little bit of mathematical wizardry and the features of a miter saw you will not only save time and effort but also help create perfectly smooth and accurate cuts every single time. For better results, try not to use a cheaper blade.