Why Doesn’t My Band Saw Cut Straight?

If you buy something through a link in our posts, we may get a small share of the sale.

Band saws are some of the popular machines in the saw family and are used for cutting foam, wood, metal, and more. Most woodworkers use the band saw for getting zigzag cuts for unique designs rather than achieving a straight and even cut on their work piece.

One of the problems that you may encounter when using the band saw is when it is not cutting straight. So, why doesn’t my band saw cut straight?

1. Dull Blade

Apart from selecting the right blade, you must ensure that it is sharp. A dull blade will never cut well like a new sharp blade. Furthermore, band saws that have dull blades tend to cut more slowly and crooked.

When the band saw blade is sharp, the operator will not require much force to push the piece or band saw project they are working on into the blade and get the right cut. If the blade of your band saw is dull, much more force will be required to push the work piece hard into the blade. To get a straight cut, you must ensure that the blade is sharp.

2. Blade Running in a Wrong Direction

To get a straight cut from your band saw, you must ensure that the blade is running in the right direction. If the wiring is reversed, especially for machines that are powered by 3 phases of power, the blade may run in the wrong direction.

Man stops midway when his band saw doesnt cut straight
  • For vertical blade band saws, the working part of the blade must always go down. This will force the work piece down and into the table. If not, then the blade will try to lift the work piece from the table.
  • With horizontal band saws, the working part of the blade tends to run towards the blade wheel that is connected to the motor. You should always call a qualified electrician to correct the wiring of your blade if it starts running in the wrong direction.

3. Blade Installed Incorrectly

For a good band saw to cut straight, the blade must be installed correctly. For most blades, the right installation means that the blade teeth should be pointing in the correct direction. On the usual metal or wood cutting blade, the point of the blade or hook should point down for vertical blade band saws.

Man cutting wood using a band saw

For horizontal blade saws, the hook of the teeth must be pointed so that they can enter the workpiece first when the blade moves. No matter the size, most band saw blades may be flipped inside out, making the teeth point in the reverse direction.

On some grit edge blades and knife-edge style blades, you may get a fresh sharp cutting edge by just flipping the blade inside out. Some blades like the honeycomb style blades have been designed to run in a direction that seems backward compared to other common types of blades.

4. Worn Out or Incorrectly Aligned Wheels

If your band saw is not cutting straight, you should also check the blade tracks on the wheels. High-speed machines usually have a rounded surface or crown on the blade support wheels. The blade ought to run near or at the center of the crown and should not be close to the rear edge or front of the wheel.

Most machines will run well when the blade is ⅛ or ¼ inch from the center of the wheel. Before you make any adjustments to the blade wheels, be sure to look at the adjustment of the blade guides.

When guides are not properly aligned, they can cause the blade to track incorrectly on the wheels. If your wheels are worn out, you should resurface the blade wheels first before setting the guides.

5. Misaligned Blade Guide

If the band saw blade guide is more close to or far from the blade, then it is poorly adjusted. As a result, you will not get the straight cut that you are looking for. When the guide is far from the blade, it will not support it and you will have a shaky blade.

With an unstable blade, you can be sure to get an improper cut. If your blade guide is over tightened, you will have challenges feeding the work piece into your band saw. As a result, you will end up getting a zigzag cut. Ensure that your blade guide is well aligned for you to get a straight cut.

6. Blade Tension Is Incorrect

Industrial band saws tend to have two major blade tensioning mechanisms; pneumatic and screw over spring. With a screw over spring mechanism, there is no direct way of setting or reading the blade tension.

Band saw blade

The best way to get an exact blade tension is by using a blade tension gauge. A blade tension gauge is essential, particularly if you have multiple machines or you are working with an application.

Pneumatic systems utilize a pressure regulator valve for setting the blade tension. The manufacture usually gives a table or chart that shows the pressure to use to attain the desired blade tension for different blade sizes.

Air pressure mainly ranges from 10-12- psi. All you need to do is set the regulator to the correct pressure and the machine will handle the rest.

How Do I Fix My Bandsaw Drift?

To help with the band saw drift, try setting the fence so that it is parallel with the miter-gauge slot on your table. When you do this and keep the center of the saw blade lined up with the center of the wheel, everything should stay aligned.

Conclusion

A band saw that is not cutting straight can be quite a headache for any handyman. This is why you must go through all the above processes to ensure that the cutting power of your band saw is restored.

To completely prevent this problem, you must ensure that you use a high-quality band saw blade and ensure that it is properly installed. You should also carry out routine maintenance of your band saw to ensure that it is in perfect working condition and any issues are fixed.

An expert at home repair, remodel, and DIY projects for nearly 40 years. His first experience came in completely restoring an antique home. Completely redone from the inside out, and restored to its original form, the home is a featured design by renowned Southern California Architect Cliff May, considered to be the father of the California Ranch Home. Now Dennis spends his time on fine woodworking projects and tool comparisons.