Why won’t my band saw cut straight?
We get this question from customers quite a bit and it’s usually after some amount of frustration. Before you start tearing your saw apart, let’s take some time to review some band saw troubleshooting basics.
Tooth Count, Feed Rate, and Cutting Speed
Often, the blade is the most common culprit when it comes to cutting accuracy. Blade condition and tooth count is critical to cut quality and blades can easily be ruined if you’re not careful. Sometimes the solution is as simple as getting a new blade or using a blade that is more suited to your application. If you cut a variety of material, for example thin wall tubing and thick plate back to back, don’t be surprised if you start having issues right away. Therefore, take the time to understand the tooth count, feed rate, and speed settings required for the materials you are cutting. You may not be able to cut everything with the same set up.
Most saw manufacturers have guidelines listed in the owner’s manual (you did read that right?) and you can also get good information from the blade manufacturers. We would be happy to help as well. Band saws are versatile, but you can quickly ruin a new blade if you don’t follow the guidelines.
Correct Material Orientation in the Vise
Assuming you have selected an appropriate blade, feed rate, and speed for the application, there are still a few additional things to keep in mind. An often-overlooked detail is how the material is clamped in the vise. There is a big difference between 1×4 bar stock laid flat vs on edge. Feed rates can also vary dramatically as the saw moves through the work piece. Again, there are guidelines available, just be aware that getting this wrong can cause problems. Blade life can also be significantly compromised if the proper break-in procedures are not followed. When new, the blade tips are razor sharp and if pushed too hard too soon, they will grab. This results in damaging the shape and set on the tooth.
Realistic Expectations of Your Saw
Last thing is to know what to expect. A band saw that is set up properly for a given application should be capable of making accurate cuts to the point that your tape measure, marking method, and eyes are probably a bigger problem! Truth is, in most situations, a band saw is plenty good enough and offers a lot of capacity for the money and a huge improvement over messy abrasive chop saws. You shouldn’t expect it to be as accurate as a high-end cold saw and you should not expect your portable bench top saw to behave the same as a larger industrial band saw with a 1” blade. In general, the larger the blade width on a band saw the more accurate it will be. Obviously, there are other variables, but the point here is to understand the capabilities and limitations of your equipment.
For a lot of folks this may all seem obvious. Band saws can, and do, require maintenance and repairs from time to time, but it still pays to systematically double check the basics before you start fixing something that is not broken.
–Dave Watson – Technical Sales