June 22, 2022
The other day, my friend called in asking me to look into his bandsaw because it was not cutting straight. I told him that there are several reasons why a bandsaw would not cut straight. It might be a case of a dull saw blade, loose blade tension, improper feeding, or non-usage of workpiece guides like miter gauge or rip fence. So, you should figure out among these reasons the cause of the inability of your bandsaw to cut straight.
Bandsaws, however, come in a wide variety of models and brands. You will find metal bandsaw, meat bandsaw, wood bandsaw, benchtop bandsaw, horizontal and vertical, and many other bandsaw types. Yet, the usual culprits when it comes to a bandsaw not cutting straight are the abovementioned factors.
Table of Contents
- Primary Causes of a Bandsaw that Is Not Cutting Straight
- Tips on Adjusting Your Bandsaw
- Should You Replace a New Bandsaw If the Old One Is Not cutting Straight?
- How to Adjust the Bandsaw Blade’s Tension?
Primary Causes of a Bandsaw that Is Not Cutting Straight
As mentioned above, some factors cause the blade drift and its inability to cut straight. As an owner of a bandsaw, it will help if you are familiar with the following major causes of the bandsaw blade’s inability to cut straight:
Too Much Force Applied When You Cutting
When cutting materials using a bandsaw, you need to balance the cutting speed and the force you apply. If you force the material into the saw blade, chances are the saw blade might twist while cutting. This twisting produces a crooked cut. Hence, you only need to apply enough pressure when feeding the material you want to cut. In this way, you let the saw blade do its job with not much effort on your part.
If the saw blade is dull, you will sometimes get impatient and push the workpiece harder onto the saw blade. The saw blade will likely twist, producing a crooked cut likewise. In such a case, you must replace the saw blade or have it sharpened.
Crooked cuts are sore to look at. Moreover, if the cut is not straight, you need to redo the cut, causing you downtime. But if the saw blade is not dull, you can patiently feed the workpiece without forcing the issue. Practice getting the hang of the feeding process. Remember that the less tension you apply on the saw blade, the less likely it will twist and cut crookedly. Besides, it will help if you also use help guides to steady the material and cut straight.
Loose Blade Tension
Loose blade tension can also be a primary reason why a saw blade is not cutting straight. The saw blade stretches itself between the two wheels, and if the tension is not sufficient, it will not likely cut straight. You can check the blade tension by wearing a gloved finger and pressing in on the blade side. If you see that the blade tension is loose because you can still push it beyond a quarter of an inch, you need to tighten it up.
To fix this problem, you need to check the tension of the blade, as mentioned above. Wear your safety gloves when trying to push the saw blade. The range of recommended blade tension for a carbon-steel blade is between 15K psi to 20K psi.
Yet, saw blades vary depending on the materials they are made of. If the tension is higher than the range mentioned above, you can decrease the blade tension. But if it is lower than the range noted above, you need to tighten the saw blade.
Incorrectly Installed Saw Blade
Another reason why the saw blade is not cutting straight is an incorrectly installed saw blade. You can quickly know if the saw blade’s teeth are pointing in the right direction. Using a metal or woodcutting saw blade, the hook points downward, especially for the vertical bandsaw. If you use a horizontal bandsaw, the saw blade’s hooks enter the workpiece first. So, the hooks must face the material.
You might be asking whether you can flip the saw blade inside out. Yes, you can if you want to get a fresh cutting edge from your saw blade. If your saw blade is a honeycomb-style blade, you will see that the saw blade teeth seem to run backward.
It will be best to ensure that your saw blade gets appropriately installed and that its teeth are facing the right direction to fix this issue. If it got it wrongly installed, you should flip the saw blade over and re-install it.
Saw Blade Guides Are Wrongly Aligned
The bandsaw blade guides usually feature three components or elements. You’ll find the first two components on each side of the saw blade. Additionally, the other one gets situated at the saw blade’s rear. Guide components can come in forms like sliding blocks, wheels, or a combo of both. The saw blade should not be touching the guides during operation.
If the guides are misaligned, you can adjust them. Yet, there is no fixed set of measurements for blade guide adjustments. So, you only need to adjust the guides based on the saw blade’s thickness. You can move the guides farther or closer to the blade. Moreover, you can take the block off to move the blade guides. After adjusting, you can put back the block.
Wrong Cutting Speed
You may fail to cut straight using the bandsaw if you are sawing too fast. So, before you start cutting, you should figure out beforehand the appropriate speed for cutting the material. If you cut metal, for example, you can go slower. While if you would cut wood, you can go faster. You should speed up or slow down depending on the material you are cutting and the blade you are using.
If you are sawing too fast, you should adjust the bandsaw speed. Check the adjustment system of your bandsaw. If you cut wood, you should maintain your speed around 3000 FPM. If you are cutting metal, you can slow down up to 1500 FPM.
Bandsaw Wheels are Incorrectly Aligned
After checking if the saw blade has the proper tension, you should also check if the blade tracks on the wheels. The support wheels of the saw blade in high-speed machines come with a rounded surface or crown. When operating the bandsaw, the saw blade should run on the crown’s center or near the crown’s center. It should not be too close to the read edge or front of the wheel.
If you see that the saw blade is not on the wheel or barely on the wheel, you need to align the wheels. You should check beforehand the blade guide adjustments before you tinker with the blade wheel adjustments. The reason is that the misaligned guides can also cause the blade to move on the wheels in an incorrect manner.
The bandsaw guides do not hold the saw blade in place. They are there as backups. If your bandsaw is well set, you may not have any need for the bandsaw guides.
On the other hand, the bandsaw wheel’s crown keeps the saw blade in place. The saw blade will tend to move to the highest wheel point or the crown or its top. If you got worn-out wheels, the saw blade would go awry, not knowing where to go. This is one reason why the saw blade has difficulty cutting straight. You can resurface the blade wheels if they are too worn out before you set the guides.
As you try to learn more about the power setup of your bandsaw, you will discover that your bandsaw necessitates three power phases to operate. Such three phases can make you make mistakes with its wiring. If you run the bandsaw with the wrong wiring, you would find the saw blade running in the opposite direction.
If you are using a vertical bandsaw, its saw blade should move downward when cutting. This downward movement holds the material on the tabletop. If it moves upward, it will cause the material to get ejected from the tabletop. With the horizontal bandsaw, the saw blade’s edge should move towards the motor wheel. If your saw blade is moving in the opposite direction, it will help to check the electrical wiring of the bandsaw.
Bandsaw Wheels are Worn Out
If you’ve tried checking all the tips for troubleshooting your bandsaw, but still the bandsaw blade doesn’t cut straight, I think it’s high time for you to check the wheels of your bandsaw. The bandsaw comes with a crown for supporting the saw blade. The saw blade ideally should be running at the crown’s center. It is acceptable if it veers off a quarter of an inch to an eighth of an inch from the crown’s center.
Yet, if the saw blade struggles to stay in the proper position, it will be best to tinker with the wheels and adjust them. But as mentioned above, before you tinker with the wheels, you should first check the blade guide. However, if it is not the guide, then it must be the wheel. Check if the wheels got worn out. Such worn-out wheels can cause the saw blade to deviate much from the right track. You can crown the wheel if needed. Replace your wheels if they are too old likewise.
Tips on Adjusting Your Bandsaw
Should You Replace a New Bandsaw If the Old One Is Not cutting Straight?
Unless your bandsaw is severely damaged, you don’t need to buy a new one if it is not cutting straight. All you need to do is replace some components that are not working well, such as the blades and blade guides.
You might have other reasons for wanting to replace your bandsaw, like motor problems and electrical issues. Nevertheless, if your bandsaw is only not cutting straight, you can do some repair or maintenance to it, but not a total replacement.
Of course, you need to be cognizant of the reasons behind the bandsaw’s inability to cut straight. Once you’ve exhausted all the possible causes and your bandsaw is still not working well, only then should you replace it.
How to Adjust the Bandsaw Blade’s Tension?
Blade tension is crucial to the functioning of the bandsaw blade and your safety. Besides, adjusting the blade tension well can help make your use of the bandsaw precise and safe. You can change the tension until the blade reaches its maximum recommended tension. Afterward, you can release the tension until it stops fluttering.
You can adjust the blade tension in a few ways. One way, for example, is to use a tension scale. Yet, this method is often inaccurate, which might not yield the best results. Instead, you can employ the flutter technique. This way, you can achieve the correct blade tension with ease, and manufacturers recommend this method.
To employ this method, you will need to install a new blade. Ensure that you turn off the bandsaw while doing this for your safety. Center the bandsaw blade on the wheels. You can adjust the saw blade manually to center it. Afterward, you can close the wheel guard.
Then, try to apply tension on the saw blade just below the recommended tension level. Afterward, you can begin running the bandsaw. You can release the tension after that to achieve the correct tension.
It will help if you do this as slowly as you can. Try to release the blade’s tension a quarter turn every time you adjust the tension. If you see that the saw blade begins fluttering, you can stop the release of the tension.
Then, slowly up the tension until the blade stops fluttering. This level of tension, of course, is the perfect tension for your bandsaw blade. Once you’ve achieved the ideal tension, you can attach the blade guides again. You are good to start using your bandsaw afterward.
The blade tension will likely change after a few months of using the bandsaw. This change in tension, of course, might be due to many factors. So, it will be best to readjust the tension every few months.
This way, you can extend the bandsaw blade’s life because if it is not in the right tension, you will likely damage it. Besides, readjusting the blade tension ensures you get the correct blade tension every time you use your bandsaw.
This way, you can extend the bandsaw blade’s life because if it is not in the right tension, you will likely damage it. Besides, readjusting the blade tension ensures that you got the right blade tension every time you’re using your bandsaw.
Like the table saw, the bandsaw may exhibit an issue when cutting in a straight line. Yet, once you experience such a problem, you can always go back to the possible reasons mentioned above and check if any of the reasons noted above causes the inability of the saw blade to cut straight. In this way, you can adequately troubleshoot your bandsaw and zero in on the exact reason for the failure of the bandsaw to cut straight.
You might get daunted when tinkering with your bandsaw, thinking you’re not dexterous enough when it comes to fixing things. Moreover, the bandsaw is a huge machine that could be challenging to figure out. Yet, if you know the possible reasons, you can rule out each improbable reason and zero in on the exact reason behind the inefficiency of your bandsaw blade.
Jason is a 40-year-old woodworker, carpenter and author who have been involved in the woodworking and woodcraft industry with 17 years of experience. He is expertise in technical aspects, woodcraft and furniture building projects.