So you’ve got your Miter saw all set and ready to go, or so you thought! But, disappointingly, the first cut is not straight. First you may be confused and then you may ask why is my miter saw not cutting straight? To help you trouble shoot, we explore 5 reasons as to why this may be happening and how to fix it. So that you can get back to your project as quickly as possible.
5 Likely Reasons For a Miter Saw Not Cutting Straight
1. The Blade of the Miter Saw is Not Aligned with the Fence
The fence needs to be set at a 90º angle to the blade or the cuts will be inaccurate. This is easy to test with a T-square and a clean 90º angle must be perfect or the cuts will be bad. The full instructions for fence adjustments can be found in the owner’s manual for your saw.
But, in most cases, this is a simple unscrew, adjust and screw the fence back in place operation.
2. The Blade of the Miter Saw is in Bad Shape
This is probably the most common cause of poor miter saw cutting accuracy. It’s important to understand that blades have a finite lifespan and old blades can be very dull. They will struggle to cut through the material and the cuts are more likely to be crooked due to excessive friction.
Over time, older miter saw blades can become cracked, bent, and warped entirely out of shape and this increases the risk of a kickback. This is especially true if the saw blade is being used to cut a material that it isn’t designed to cut. If you’re using a blade that is designed for wood cutting and you use it to cut metal you can easily break off some teeth.
Regular blade inspections are highly recommended to ensure that the blade is in good condition. If you notice warping, cracks, and missing teeth it’s time to replace the blade. Using a proper blade in good condition is important when you want to maintain accuracy during cutting.
3. A Misaligned Bevel Gauge on Your Miter Saw
When you’re making bevel cuts, you need to use the bevel gauge. This will show you the precise angle to the left or right of the blade to make the bevel cuts. If the miter saw has been impacted or it’s been used excessively, the bevel gauge may be out of alignment. This can even happen out-of-the-box with new miter saws and it’s not an easy problem to offer a one-size-fits-all solution. Why?
Well, every miter saw is different, the bevel gauges will require calibration in a very specific manner and this is detailed in the owner’s manual for your saw. Take some time to read the manual and follow the calibration steps carefully. If this doesn’t fix the problem, contact customer support because you may have a faulty bevel gauge that needs to be replaced.
4. The piece of wood Your Working with is Not Clamped
When you’re sawing bevels with a miter saw, it’s important to clamp both pieces of wood. During a bevel cut the saw angle is facing toward the bevel angle and the spinning blade can draw the work piece back into the blade. This may result in cuts that are not straight and the easiest solution is to clamp the work-piece down.
This approach can be equally applied to other cuts too because any work piece that moves is less likely to be cut straight.
5. A Misaligned Miter Gauge on Your Saw
This is a similar problem to a misaligned bevel gauge that we discussed above. In fact, if you have a misaligned miter and bevel gauge, it can be difficult to determine which problem you need to resolve first. These problems are more common when saws are in constant use for an extended period of time or they have suffered some kind of significant impact.
Another common cause is a miter saw that’s been used by an inexperienced operator that’s fiddled with the miter or bevel gauge. Although it is true that new saws may have this problem out-of-the-box, this is less common unless you’ve purchased a poor-quality saw.
A cheaper miter saw is less capable of accurate cutting because the miter gauge is poor and it tends to go out of alignment easily. But, if you have a good saw and it cuts accurately the solution is to realign the gauge.
Again, we cannot offer too much advice on this topic because the instructions will differ depending on the specific saw that you’re using. When in doubt it’s always a good idea to consult the owner’s manual and if you’ve misplaced it you can usually find free pdf copies online.
Tips For Making Your Cuts With A Miter Saw Better
To finish let’s take a look at three general tips that will improve the accuracy of your miter saw cuts and to help prevent your Miter Saw Not Cutting Straight:
1. Full Speed Saw Blades when Using Your Miter Saw
It’s important to have a blade spinning at full speed if you want to improve and maintain the accuracy of your miter saw cuts. When you start the saw, resist the urge to start cutting immediately and give the blade time to reach full speed. This only takes a few seconds, but the saw blade can get through the material easily and the cut will be far more accurate.
2. Use a Clamp to Hold the Pieces of Wood in Place
Making bevel cuts is less accurate if you don’t use a clamp on the work-piece. The saw positioning will pull the material into the saw as you’re cutting which promotes inaccuracy. Always use clamps and you will notice that your cuts are more accurate this is especially true if you’re making a bevel cut.
3. Don’t Rush the Blade When Cutting Wood
The blade is designed to cut firmly, but you should avoid rushing the blade or you may produce an inaccurate cut. Make sure that the blade is spinning at the optimal cutting speed and make gentle and steady progress through the material. If you rush the blade, you will cause the saw blade to wear out earlier than expected too.
Conclusion: Reasons Miter Saw Not Cutting Straight
As you can see, there are a number of reasons why a miter saw not cutting straight can become a problem. All woodworkers understand the importance of accurate cuts to complete their projects. Repeating cuts reduces productivity and efficiency which may be less of a problem for hobbyists but it can have a huge impact on a new business. If you want to master woodworking, producing accurate cuts must be a top priority.
I’m Thomas Steven with more than 12 years of experience in woodworking. It has always been my passion to become a successful woodworker. I have completed hundreds of successful projects. This blog is a way of sharing my woodworking experiences and what tools get the best results. I write about woodworking while being an associate with Amazon and I earn a little commission from every qualifying purchase.