Proper Blade Tracking Is Essential for Band Resaws, Quality Lumber
Proper Tracking of a Band Resaw Blade Is Important
By Sam Baker
Date Posted: 9/2/2003
Proper tracking of a band resaw blade is important to the overall operation of the machine and to the quality of the finished lumber.
The following article describes general troubleshooting methods to determine and correct tracking. Specific questions regarding a particular brand of machine should be referred to the manufacturer.
Proper tracking is achieved by correctly aligning the two wheels of a band saw. Normally, one wheel is fixed and one wheel is moveable. On some machines, both wheels move. There are three distinct movements or alignments: vertical (top to bottom), in or out, and horizontal (left to right).
You will need to begin by removing the guides. You cannot properly track a machine if the guides are pushing the blade up, down, in or out. Guides should be set after the blade is tracked. There is no point in setting blade guides to a blade that tracks poorly. After removing the guides, put a blade on the machine and tension it properly.
First align the two wheels in the vertical plane. Use a 2-foot level for this purpose. Take the level and hold it vertically against the fixed wheel. Gauge the bubble, and then put the level on the moveable wheel. Adjust the moveable wheel to match the fixed wheel in the vertical plane. They should be as close to identical as possible. If they are not perfectly aligned, it will become obvious later, and you can return to this step.
After you have the wheels aligned in the vertical plane, you will need to check and see if they are aligned across their centers. The moveable wheel may need to be adjusted in or out. The wheels may need to be aligned across their centers even if the hubs or bearings have not been changed or a wheel has not been removed for any reason. They may have slipped in or out. Note: It may be necessary to back the blade tension down in order to perform this step.
Generally you can measure off the framework of the machine itself for this alignment. Measure to a center point on the wheel, either the face or the back of the wheel. Either wheel usually is moveable straight in and out. Make sure you do not get the drive wheel out of line with the drive belt. Once you have aligned the wheels across their centers, you are ready for the final step. If they are not perfectly aligned, it will become obvious later, and you can return to this step as well.
The final step of moving one or both wheels left to right achieves true tracking movement. Adjusting the movement wheel left or right allows you to move the blade in and out on the wheels. You want the bottom of the gullet on the blade to track right on the face of the wheel or up to a 1/16-inch off the wheel. Any location other than that and you will have problems.
As you make the adjustments left to right on the wheel, carefully turn the wheel by hand to see where the blade tracks. Be careful. I have seen set-ups that were so far out that the blade will jump completely off the wheels.
As you make these set-ups, hit the wheel at four points (top, bottom, left, and right) with a rubber mallet. This helps ensure that it actually moved when you made the adjustment and that everything is seated to the new adjustment.
After completing these steps you are ready to run some tests to see if everything is where it should be. If the blade does not track properly, now is the time to correct it.
The first test is to turn the wheels forward. If the blade tracks on one wheel but not the other, they are probably mis-aligned in or out, and you should repeat step #2.
If the blade tracks properly on both wheels as you turn them forward, you are ready for the final test. Turn the wheels backward; if the blade stays where you put it, the blade is tracked perfectly. If the blade tries to come straight in or out, the wheels are not aligned in the vertical plane. Repeat step #1.
In order to visualize how a blade that is tracked too far forward will react, imagine that the blade is a 1-inch wide rubber band. Imagine putting it on the wheels and letting 1/8-inch hang off the front of the wheels while stretching it. The front edge of the rubber band would fold in; it cannot take the stretch. A steel blade will react exactly the same except you cannot see it.
The leading edge of the blade does all the work, and it must have proper tension to cut properly. Little or no tension is applied to that portion of the blade that hangs off the wheels. Another problem with a blade that hangs too far off of the wheels is that the blade folds in like the rubber band. This causes the blade to have lead up or down (bend slightly up or down), depending on whether you have an under-slung head or an overhead model.
Here are a few examples of problems that can be caused by improper blade tracking .
1.Blade dives or climbs throughout the cut.
Reason: lack of blade tension. Many things can contribute to lack of tension, including a blade that hangs too far off the front of the wheels. Remember the rubber band example.
2. Blade lifts one side of the wood.
Reason: blade is in a twist. The wheels most likely are not aligned vertically.
3. Blade cuts well at first, but then starts diving or climbing on the tail of every cut.
Reason: blade is running too far back on the wheels, knocking the set out of the blade, or the blade is hanging too far off the front of the wheels, bending up or down.
Tracking is a critical part of proper band resaw set-up. Many things can effect tracking. One of the most important factors is the crown of the wheels. A properly crowned wheel helps hold the blade in place and promotes proper tracking.
Over time, the crown wears, and it must be re-crowned. Some machines come from the manufacturer with flat wheels; even these need to be re-trued over time. Others have from 0.004-inch to 0.009-inch rise in the center of the wheel. I personally recommend 0.009-inch crown and a true curve on the wheels. A curve is easier on the blade than an inverted V. Less than 0.009-inch is fine and probably is easier on the blade; however, it must be redone more often.
Depending on usage, most wheels need to be re-crowned at least once a year. Many companies may go for longer periods of time before re-crowning wheels. However, they could be losing thousands of dollars in extra blade costs – not to mention getting poor quality cuts. Many local machine shops have the ability to re-crown wheels, and several companies offer re-crowning equipment.
I have tried to stay as basic as possible in this article, so I have not referred to specific bolts to turn to move the wheel a particular direction. I believe it is more important to understand the principals of the machine and what to look for.
All machines are different, but by using this article as a general reference guide and consulting with the original manufacturer, you should be able to make the necessary adjustments on your machine to get the desired results. For specific instructions please refer to the original manufacturer.
Band resaws are capable of consistently producing the highest quality lumber. Hopefully, this article will help you get the most from your machine.
(Editor’s Note: Sam Baker is the owner of Samuel Kent Baker, Inc., which supplies machinery and equipment to the pallet and sawmill industries. He may be contacted at (866)544-0538.)
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