Circular saws are incredibly handy. They can make all sorts of cuts, and the portability allows for an insaneamount of freedom when working. But that non-stationary nature can also make these saws tougher to work with.
Most of us have botched a cut by taking the blade out of line, be it a straight or a miter cut.When it comes to crosscuts, where you often have to cut across the grain, it’s easy to see why maintaining the course is tricky.
That’s where building a circular saw crosscutting jig can be a lifesaver. This device keeps the saw in line and prevents any crooked or misaligned cuts.
In this guide, let’s look at how to build a DIY crosscutting jig and make those cuts straight as an arrow.
Should You Even Build a Crosscut Jig?
We’ve got miter saws for crosscutting, which do an excellent job. So, why bother making a jig?
The first obvious possibility is that you only have a circular saw — but not justbecause you don’t own one.
For instance, many woodworkers rely on their circular saws due to how portable and accessible they are. It’s easy to see why, as miter saws have a much larger footprint. Using a circular saw makes more sense when portabilityis an issue.
And for circular saws, making crosscuts isn’t all too difficult, either. The issue is that most of these saws don’t come with a fence to keep things in place.
Furthermore, it’s easy to create longer jigs if you have to make really wide crosscuts that a miter saw cannot perform.In such cases, it makes sense to build a crosscutting jig.
Building a Circular Saw Crosscut Jig
There are plenty of ways to build a crosscutting jig for a circular saw. Some users create two rails with a space roughly equal to the saw’s width. The saw then slides through the rails to cut workpieces.
Alternatively, some emulate a fence, where the saw has a straight boundary on the opposite side of the shoe. The saw then moves along it to make cuts. Either one works well enough, but I find the former to be more reliable.
Hence, we’ll create a jig that uses asliding rail to guide the circular saw back and forth. Let’s get started.
Choosing the Material
The best thing is that one can build it only with scrap lumbers. I made mine out of particleboard pieces, for instance. But remember that not every material will work for every portion, and their properties vary.
The material will fulfill a few roles here — the base portion, the bottom and top rails (two of each), and a bunch of blocks to act as spacers.
For one, softer materials like hardboard shouldn’t be the base, as the saw would be too heavy for it. Most materials will be fine for the top rails, though.
Alternatively, acrylic can do a decent job of being the base. Proper wood like pine or oak is certainly another great option if you have some lying around.
For smaller jigs’ rails, many use low-friction plastic as well, which allows the saw to slide along effortlessly.
However, be mindful of the movement within the material. If you’re using actual lumber, make sure that you change the grain’s direction.
That ensures that any movement will be vertical and won’t affect the jig’s measurements. Using metal rails to eliminate this issue is also feasible if you’re willing to go through the trouble.
Reducing moisture absorption by sealing the wood is another way of keeping this margin to a minimum. In essence, knowing the material and its properties is crucial.
The Measurements
The length of the jig depends entirely on your needs. If you only make shorter crosscuts or require a portable jig, I suggest staying with a compact one. If it remains in the workshop and has to cut wider lumbers, go crazy.
If the jig’s too long, make sure that the material you’re using for the top rails and support is rigid enough to handle it.
The second measurement is for the width of the saw. Measure the plate’s width from one end to the other. This will be the width of the top guiding rails, which keeps the saw in line.
Thirdly, we need to determine the height of the jig, namely the riser blocks. This is crucial, as too high wouldn’t provide enough depth in the cuts.
The Process
Let’s begin by creating the base. I used a 3/4” piece of plywood, but you can use anything else.
Once we have that, it’s time to set up the risers to the optimal height. This depends on your saw and blade, so I won’t go into the exact measurements here. If you want the rails to sit beside the saw’s shoe, thenthe risers’ height is the height your blade will be cutting through.
However, if you want the rails to be below the saw’s base, then you have to account for the rails’ height as well.
Once everything’s in place, clamp the blocks in place and glue or screw them onto the base of the jig.
The next step is to get the guiding rails in place. Make sure these pieces are completely square and perpendicular to each other. Otherwise, the cuts you make with this jig will all be crooked.
Since we have the width of the saw, create two marks on the riser that equals that width.If your rails are going to be beneath the shoe, try cutting a workpiece to ensure that the blade is cutting deep enough.
Once that’s done, clamp the rails down in place and double-check whether they’re square. Then, begin screwing them down to the base.
If you’re using glue, make sure that none of it comes out and stays in the saw’s path once you clamp down. Otherwise, that can affect the cut.
And that’s all there is to it! You can also install a small block and screw one end to the base to create miter cuts by rotating it to different angles.
A Crosscut Jig without the Rails
If you want something even more minimal, you can use a fence and leave the other end open. Take a plain board or piece of wood.Measure the distance between the circular saw’s blade and the farthest edge of the base. This is the distance at which we’ll install a fence to guide the saw.
Afterward, take a smaller piece of wood, make sure you’re at a 90-degree, and glue or screw it on the base. Only the length of this fence matters, and even that depends on how wide your crosscuts will be. Any height will work fine, as its only purpose is to prevent the saw from moving past it.
My Last Words!
Circular saws allow for remarkable freedom and portability, but that freedom can come back and bite you back, especially for crosscuts. As shown above, building a circular saw crosscut jig is surprisingly straightforward. All you have to do is get the measurements correct, and the rest is smooth sailing.
