7.4 Saw Operations, and Handling
Tim A. Bacon
Horizontal Saw Operations
Prior to starting your job, tie back long hair, secure loose clothing, remove jewelry, and always wear safety glasses. Here are some basic steps to follow when using a horizontal band saw to cut material.
Determine the proper RPM for the saw. It is common for the saw to be set up for surface feet per minute (SFM). This is based on the type of material to be cut. Aluminum has an average SFM around 700; mild steel is closer to 66 SFM. In general, cut hard material with fine teeth at a slow speed and soft material with coarse teeth at a high speed.
Recall that the three tooth principle states that the material to be cut should be thicker than three teeth on the blade. If the material is too thin, you’re likely to break off the teeth of the blade. By having three teeth of the blade always in contact with the material while cutting, the blade and material are supporting each other, and there is constant pressure between the blade and the material. When there is only one tooth engaged with the part, there will likely be damage to the blade as a result of the single tooth hitting the material. If the material is too thin, less than three teeth thick, the force of a single tooth hitting the material will cause a fracture or chip the tooth. This will destroy the blade and require that a new one be installed. If necessary, choose between changing the blade to a larger tooth per inch (TPI) blade or getting a piece of sacrificial material to increase the thickness of the material being cut.
Author’s Tip
Stack up several parts to be cut. This will increase the material thickness AND increase the productivity of the project. In fact, when the boss sees this, you may get the employee of the month parking spot!
Adjust the guide arms on the leading and trailing sides of the part as close as possible to help support the blade during the cut. If the arms are too far apart, the blade may be damaged. Having the guides significantly away from the material being cut will also allow the blade to bend or twist. This can damage the blade and waste material.
Most machines have a chart as a guide to determine the speed of the blade needed for a given material. Adjust the speed (RPM) if needed.
Never start the blade when it is in contact with the part. It is common practice to start the blade when it is about a ¼ inch away from the part.
Lower the blade slowly to engage the material. Dropping it fast can damage the blade. Verify that the blade is creating chips. If the feed is too slow, it will be rubbing more than cutting, which generates heat and hardens the part. This will also shorten the life of the saw blade. Increase the feed once the blade has made contact to produce a proper chip.
After every sawing operation, the part should be deburred in preparation for the next step.
Set up the horizontal saw with the guides close to the part, as shown.
To cut long bar stock, pull the desired amount of mater