If the blade’s teeth slice off material faster than the gullets can carry the material away, that material compresses to the point that it can’t compress any more, then it starts pushing back on the blade. Mattias Wandel has an excellent visual explanation and accompanying video titled, The Physics of Bandsaw Resawing, but the same principles apply to any blade. If you still have problems with blade drift after trying a sharp 3-4 TPI blade, there is a great video by Alex Snodgrass demonstrating how to properly set up your bandsaw and guides.
Band saw blade drift is a tendency of the blade to veer to the left or right while making a cut using the rip fence. The point of the last paragraph is that if the band saw is not set up properly and/or does not have a good quality, sharp blade installed and tensioned correctly, the chances of accurately adjusting for drift are minimal at best. Since there is little that we can do about blade drift at the blade, we adjust the fence to match the drift angle to essentially cancel it out.
Being a happy bandsaw owner has a lot to do with your approach to coping with the fact that a bandsaw simply will not cut straight, or, in the sage words of veteran woodworkers, “Adjusting for drift.” Even the top performing 14″ bandsaw on the market, Powermatic’s 14 Bandsaw 1791216K, comes with a no-frills fence with 4 bolts on top rather than easy and obvious thumbscrews or knobs that say, “Adjust me here!”. Making the bandsaw cut nice and straight with this fence is a snap.
The amount of drift varies with every blade, but you can compensate for it by clamping your fence to match the drift angle. SINGLE-POINT FENCE. Another way to overcome blade drift is to use a single-point fence like the one shown in the left photo above and in the margin. SETTING THE FENCE TO COMPENSATE FOR BLADE DRIFT. FEED RATE & TECHNIQUES. With either style of fence, your saw will help you determine the feed rate for resawing.
On a typical wood or metal cutting blade the hook or of point of the blade should be pointing down for a vertical blade bandsaw, or for a horizontal blade saw the hook of the teeth should be pointed such that they enter the workpiece first as the blade moves. During regular cutting on a well set up bandsaw the blade will move or bow backwards a bit as you press the workpiece into it. The side guides will assist in keeping the blade cutting straight, but they are not an iron lock on the blade forcing it to cut straight.
My playing around over the past few years seems to confirm the suggestion that presuming a correctly sharpened and jointed blade that can/has cut straight that the onset of drift is mostly to do with position of the blade on the tyres – that if a previously straight cutting blade starts to drift that it’s probably that the blade has moved on to a different part of the tyre. The other possibility is that something other than normal wear has happened to make the blade cut differently off one side than the other if a problem suddenly kicks in – but it should keep on tracking OK with normal even wear. Prime suspect with a new blade on a saw that has previously been OK has to be a misaligned weld, or a badly sharpened blade…. ian.
why does my bandsaw drift Related Question:
Why is my band saw cutting crooked?
When the band saw cuts crooked, a dull blade, improper feeding, loose blade tension or not using a work piece guide could be the cause. Use the rip fence or miter gauge to guide the work piece uniformly through the cutting blade to make straight cuts.
How tight should my bandsaw blade be?
The blade should deflect no more than 1/4 in. A good place to begin is to tension the blade until the meter reads proper tension for the next wider blade. For example, if you’re tensioning a 3/8-in.
Why does my bandsaw spark?
Ceramics can cause sparks. Or, if your thrust bearing is too far past the blade, more toward the center of the bearing than the edge, then it won’t turn and you’ll get sparks too, and possibly wear a groove in the bearing.
How long should a bandsaw blade last?
On average your bandsaw blade should last 6 months to as long as a few years depending on what your cutting with it. Make sure to match your blade strength and quality to the project and material your cutting.
Why do bandsaw blades break?
Machine Defects Even the best blades can fail if there is something else wrong with your bandsaw, and even a small misalignment of bearings or guides can put a twist in the blade as it goes around. Resulting in tension being applied in all the wrong ways which will lead to early breakage.
Where should a bandsaw blade sit on the wheel?
Make sure the machine is disconnected from the power supply. When tracking, you always want to make sure that the blade is sat on the crown of the wheel, with the deepest part of the gullet in the centre.