Structural cutting can present unique challenges and put your band saw blade to the test. Read on to learn more about four key challenges and how to achieve optimal cutting results.
Challenge 1: Pinching
When cutting structural shapes and I-beams, one common problem is the pinching of the saw blade, causing the blade to break or stop cutting in the material.
This happens as a result of either residual stress in the piece being cut or how the part has to be held in the machine. In either case, the material being cut pinches in on the back of the saw blade. This causes the blade to stop rotating or fracture.
For applications where this is a problem, use a wide set – or wide kerf – blade option. This means the band saw blade teeth are bent further on both sides than a standard blade design. This will cut a wider channel for the part, allowing the blade to progress without pinching.
Watch our tech tip on pinching.
Challenge 2: Bundle cutting
Bundle cutting of various solids and structural shapes can be one of the most challenging applications for band sawing. Irregular size, shape, and surface of materials can result in loose bundles and spinning parts, increasing the opportunity for premature blade failure and machine damage. Properly positioning and securing the bundle will provide the best opportunity for successful cutting.
Some band saw machines have been specifically designed for bundle cutting and are equipped with both a side and a top hold-down vice to aim in holding the material secure during the cutting operation. For those types of machines, the bundle needs to be stacked so when the top hold-down vice is engaged, the pressure being applied is equally distributed across the entire width of the bundle. The advantage of having both vices is that the material can be stacked in either a vertical or horizontal orientation.
Some band saw machines are only equipped with side vices, requiring special positioning and securing methods. For these machines, adding banding, clamping, or tack welding the ends of the material will provide holding support. Orient bundle pieces so that the holding pressure of the side vices is evenly distributed across the entire length of the bundle. Avoid stacking material in the vertical orientation.
Regardless of the type of machine being used, materials should be evenly stacked and tightly bound. The best stack or bundle of material is the one that has the fewest, smallest gaps between pieces.
Watch our tech tip on bundle cutting.
Challenge 3: Choosing the right tooth size
Choosing the right size tooth per inch (TPI) size is important when working with structural materials that can be oddly shaped. You want to choose a tooth size that will ensure a minimum of three teeth are in the application at all times. Ideally, having 6-12 teeth in the cut is the optimal size range.
When blade teeth are too large and too far apart, they can straddle areas that you are cutting, causing shock to the teeth and tooth strippage. If you are using too small of a tooth size, meaning too many teeth are in the cut at once, you are also at risk for strippage or crooked cuts.
Challenge 4: Material positioning
How you position the material you are cutting in the band saw can have a great impact on your band saw blade life and the overall cutting results. Avoid cutting with the blade parallel to the material. This can lead to cutting very long sections and too many teeth being in the cut at one time, which puts you at risk for crooked cuts and stripped teeth. Angling the material – also called a canted cut – allows you to cut through the thinnest cross section possible, and with the optimum number of teeth in the workpiece at all times.
The Morse solution
Challenger bimetal band saw blades from Morse are the solution for structural cutting and deliver a long blade life, straight cuts, and less vibration for quieter cutting. Ideal for bundle cuts, interrupted cuts, low alloy steels, I-beams and carbon steels, Challenger is most commonly used by steel service centers, fabricators, structural beam, channel, and specialty shape steel manufacturers, and I-beam manufacturers. And with a wide kerf option also available, pinching or binding in even the most hard-to-cut applications is never a concern.