Hacksaws are a common workshop tool. The frames come in a range of shapes and sizes. For any given frame there’s a range of available hacksaw blades to cope with different materials and situations.
The hacksaw frame can be adjusted to take different blade lengths and when the blade is placed in the frame and it is tightened to the correct tension by a tensioning device such as a wing nut.
The hacksaw blade must be of the right pitch which is determined by the number of teeth in an inch of blade. A blade with many teeth per inch has a fine pitch, one with few teeth per inch has a coarse pitch.
The saw blade should be inserted into the frame so that it only cuts on the forward stroke. This is because the teeth gather the metal being removed and can only get rid of it when they come clear of the cut. If a blade cutting through a thick section of metal has too many teeth, in other words the pitch is too fine, they can clog up and stop cutting.
On the other hand, when cutting a piece of sheet metal, if the blade is too coarse the saw teeth could be stripped off of the blade at it try's to cut.
As a rough guide you can determine the correct blade (and number of teeth) by laying the blade across the section being cut. Normally, at least 3 teeth should touch the metal at that point. This will ensure that the blade can do its job.
After the job is done, the tension on the blade should be loosened, to prevent the frame from distorting over time.
Cutting large holes in panel steel or thin sheet metal is done by a hole saw. The drill in the center locates the saw accurately and leads it into the surface.
Repetitive cutting through thick sections of material can be hard work, unless you have an abrasive cut-off saw.
These are rated in different sizes, usually from about 250 millimeters to 500 millimeters or 9 3⁄4 inches to 19 1⁄2 inches. That refers to the largest diameter cutting wheel that should be fitted to them.
This is a powerful tool and it demands every precaution. Wear protective clothing, with nothing hanging out or loose, especially long hair. You should cover long hair with a snood cap and of course, wear safety glasses or a full-face shield. The guard on the saw should be properly in place, and the power cord well away from the cutting wheel. Flying Sparks are normal when using this saw, the range of these should be limited by placing a safety screen around the job.