You make a cut, pull back the wood, and boom, there are burn marks all over it. I’ve been there.
The main reasons your saw burns the wood includes:
- The wood species is prone to burning.
- Cutting too slowly with the saw.
- The blade is dull.
- The blade is dirty.
- The tooth count on the blade is too high.
- The blade is installed backward.
If your saw is burning the wood as you cut, there are several possible causes for the problem. Some may indicate a problem with the blade, while others may be as simple as incorrect operation of the saw. Luckily, it’s a pretty easy problem to fix!
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6 Reasons Your Miter Saw Burns The Wood
There are several reasons that your miter saw burns the wood as it cuts. You will notice brown scorch marks on the ends of the wood where the blade has cut through.
In some extreme scorching cases, you may even see the wood begin to smoke as the blade cuts through the timber.
(I’ve actually set off the fire alarm a time or two cutting with a dull blade. True story.)
Other symptoms can include the saw struggling to cut the wood, as well as tear-out and other signs of a poor cut.
Regardless, lets get into why this happens.
1. A Dull Blade Is Burning the Wood
A saw blade that is well used and is starting to dull will take longer and work harder to make the cut, creating more friction and resulting in the burning of the wood.
Frankly, 99% of the time, this is the reason I have burnt wood after cuts.
However, if you’re still not sure, another symptom of a dull blade is that the cut is not as clean as you would expect, and you need to apply more pressure to get the blade to cut through the wood.
Consequently, if the wood is scorched, you have difficulty making the cut, and the cut is not clean, then the most likely cause is a dull blade.
Replacing the saw blade with a sharper version will obviously solve the problem. Make sure to unplug your saw first!
2. Cutting a Different Type Of Wood
If you are using a new wood species for the first time and you notice that your miter saw is burning the wood, the wood may be the cause.
Certain types of wood species are more prone to scorch marks, like cherry, maple, and purpleheart.
Using these wood species in your projects makes some level of wood scorching during the cut inevitable.
This could also be the case if you’re cutting hardwood for the first time.
When I was cutting oak for my countertops, the miter saw blade that had done a great job on pine stalled and burnt the wood on every cut. The species, combined with a dull blade is what caused the issue.
3. Cutting the Wood Too Slowly
Cutting wood too slowly allows the spinning blade to contact the wood for too long. The friction produced between the blade and the wood causes heat to build-up and create burn marks.
Fortunately, the solution to this particular scorching problem is easy. Simply make your cuts through the wood a little faster to minimize the time the blade stays in contact with the wood.
If you’re cutting as fast as you can, and you’re unable to increase the feed rate through the wood, chances are you’ve got a different problem (likely that the blade is dull or dirty.)
4. A Dirty Blade Is Burning The Wood
Cutting sticky wood like pine will leave sap and resin deposits on the saw blade. As these deposits build up, the friction between the blade and the wood being cut will increase.
Just like with a dull blade, the extra friction created will heat up the wood and cause burn marks.
If you’re confident that a dirty blade is the only problem, cleaning the blade can solve the problem.
Unplug the saw and remove the blade. Then dip it in a container of soapy water. I recommend using dish soap, since it’s intended for breaking down sugars and grease.
A toothbrush would also be helpful for scrubbing here.
To be completely honest, most of the time if I suspect a dirty blade is the problem, I just replace it altogether.
Usually at this point, I’ve used the blade enough that it’s pretty dull as well, so I don’t waste my time cleaning, and just move on.
5. A Saw Blade With Too Many Teeth Can Burn The Wood
A fine-toothed saw blade will have more densely packed teeth than lower-toothed blades. Therefore, sawdust can build up quickly, increasing friction between the blade and the wood.
Additionally, the higher tooth count increases the surface area of the saw blade that is in contact with the wood. This generates more heat between the blade and the wood.
Combining these issues results in the scorching of the wood in the cut. This problem is particularly prevalent when cutting hardwood with a fine-toothed blade.
The solution is to have a few different blade types on hand for cutting different types of wood. If you’re working with a harder wood, do a test cut first, and if you notice burning switch out your blade until you’re happy with the cut.
6. The Saw Blade Is Installed Backwards
While this issue may appear to be an obvious problem, you will be surprised how frequently this mistake is made, particularly by new saw users.
The direction of rotation is indicated in your saw’s user manual. However, if you are not paying attention when installing a new blade, installing the blade incorrectly is possible.
This will not only cause the wood to burn when you try to perform a cut, but it is incredibly dangerous. The reverse position of the blade can dislodge teeth from the blade, causing them to be ejected from the saw.
If this is the cause of your miter saw burning the wood, you need to immediately stop using the saw, unplug it from the electrical outlet and remove the blade. Inspect the blade for damage.
If the blade is damaged, do not use it, and instead replace it with a new blade. If the blade is undamaged, re-install the saw blade in the correct orientation for the type of saw you’re using.
Table saws, circular saws, and miter saws all work differently, so make sure you’re installing the blade correctly for the saw you’re working with.