Most woodworkers would agree that for making curved cuts, the band saw is the tool of choice. The main exception would be for very tight curves on intricately small pieces, in which case a scroll saw would be a better option. However, both are typically tools that are found in a woodshop and aren’t very handy when portability is a requirement, such as on a construction site.
In that case, a jigsaw is likely your best option for making a curved cut. Jigsaws use a straight blade that cuts with an up-and-down motion, and the body of the saw is rotated to stay aligned with the curved cut line. However, cutting with a jigsaw can be a bit of a challenge, particularly when the blade begins to dull or if knots are encountered.
Additionally, a jigsaw blade can tilt as it heats up, so that the cut isn’t square to the face of the board, which can be especially problematic when cutting thick stock.
So, How Can You Get The Best Results When Using A Jigsaw?
To begin, always start with a fresh, sharp jigsaw blade. Jigsaws have a limited range of motion, typically no more than about 3/4 of an inch up and down. So, when cutting think stock, only about a third of the teeth of the blade are actually engaged with the stock. This section of the blade can heat up quickly and cause the wood to burn as you cut through it, so a fresh blade should cut more cleanly than one that has some wear, particularly in the same region of the blade needed for cutting the current piece of stock.
Also, when cutting with a jigsaw, don’t be in any hurry to get through the cut. By charging forward too quickly, your blade will heat up faster and it will be easier for the blade to take off on its own, making it more difficult to follow the cut line.
Cutting with a slower forward motion means you’re in control, not allowing the jigsaw to take control. It also means that the blade will heatless and as such, it should last longer.
For curves of a relatively large radius, try using the orbital action function of your jigsaw (if it is so equipped). This adjustable action found on many higher-end jigsaw models actually angles the blade forward on the up-swing and back on the downward swing. This action engages more of the blade, and cuts only a part of the board’s thickness at any moment, instead of the standard up and down action, which engages the entire thickness of the board at the same time.
Cutting tight curves can be a challenge with a jigsaw, particularly with the orbital action engaged. However, keep in mind that unless you need to use the wood on both sides of the cut for your project, you can use the cutoff portion as a runoff area to help complete the cut. In other words, if a cut is too tight, or if you need to approach a part of the cut line from a different angle, you can guide the saw blade away from the cut line and into the scrap material to remove some of the excess stock, then return to the cut line from a different angle, only to clean up the cut at a later point, from a different angle.
Also, if you need your cuts to be very smooth for the final product, you’ll not achieve this solely with a jigsaw. An oscillating spindle sander (or a drum sander) does wonder for cleaning upcurved cuts, but you’ll need to accommodate for the material that will be removed by the spindle sander. In such cases, don’t cut right up to the line with your jigsaw, but instead, cut just off of the cut line, and then clean up the cut right to the line on your spindle sander. You’ll end up with a much smoother and cleaner finished cut than with the jigsaw alone.