How to cut metal with a jigsaw
A jigsaw is a hand-held power tool that is operated by a squeeze trigger in the handle and is designed to cut sheet metal, pipework and wood. As with most power tools, jigsaws vary in the features they offer; for the hobbyist or DIY enthusiast a standard model fitted with the right blade will handle most workshop jobs with ease. For heavy-duty metal cutting, a more robust professional jigsaw would be more suitable as these can cut through 10mm steel and up to 30mm thickness on non-ferrous metals.
Jigsaws are not suitable for plunge cutting metal, however, a hole can be drilled to feed the blade through and then the cut can be continued in the usual way. Jigsaws have good manoeuvrability which makes them ideal to cut quite intricate shapes;, on tight curves it is advisable to make relief cuts to reduce the risk of the blade binding, however, this will only be possible if the cut off side is scrap, otherwise, it may be possible to get as far into the curve as possible then withdraw the blade and approach the curve from the uncut end.
Jigsaw blades have a single row of teeth along one edge of the blade, these are arranged in a small wave pattern from left to right- a blade with 21-24 tpi is recommended for cutting metal and one manufactured with a bi-metal construction will offer the best durability.
Tips for cutting metal with a jigsaw.
- Wear appropriate PPE, this should include eye and ear protection and good quality gloves. The cut off metal will fall, it is prudent to wear sturdy, reinforced toe work shoes or boots.
- Mark out or score the cut lines.
- Securely clamp the workpiece to the work bench. If there will not be sufficient depth clearance for the blade, the metal can be placed on rails and then clamped to ensure blade clearance. Some metalworkers ‘sandwich’ the metal sheet between two thin sheets of wood to add support while cutting- this technique will take longer but will help minimise distortion on soft or thin metal.
- With the power supply turned off, select the appropriate blade and insert it into the saw, ensure it is secure and correctly tightened. This is also a good time to check the settings are correct for cutting metal; this will include making sure the blade is set in a straight down position for metal cutting and not angled forward on the wood setting. If the surface of the metal will mark easily, the shoe of the saw can be covered with masking tape to help protect the surface finish. When all settings are correct, keeping fingers clear from the trigger switch, switch on the power.
- If starting the cut at the edge, press the saw shoe firmly on the surface of the workpiece without the blade touching the metal. Slowly depress the trigger and once the blade is moving, glide it into the workpiece. It is important not to force the speed of the cut and just let the blade do the work. If starting the cut away from the edge of the workpiece, simply drill a hole large enough to insert the blade in and continue as above.
- Once the cut is underway, pause the saw and add a few drops of tapping and cutting fluid to the cut to reduce heat at the blade then continue. Apply cutting fluid as required.
- Move clamps and rotate the work as necessary to gain the best positioning of the saw to achieve the best cutting line.