It sure would be nice to have a table saw setup in the garage. It would also be sweet to have a hot tub home theater in there, but life is full of disappointments.
Fortunately, you don’t need a table saw to get perfectly straight cuts out of sheet materials. All you need is a Circular Saw and a Guide Track, and you can get all the perfectly straight cuts you need.
And while we’re on the subject of “glass-is-half-full” rationalism, you’re going to find that using the circular saw and guide track over the table saw will be easier because you’ll be moving a bantamweight circular saw over plywood rather than a heavy sheet of plywood over the table saw.
There were a few slightly variant techniques to execute the perfectly straight cut– with various tools– but we were most impressed with Jay Bates’ method on Instructables.com, and we used that as our road map.
So, without further ado, the perfect cut:
Tools and Equipment Needed
- Some Clamps
- Safety Goggles (“Duh,” right? No “duh!” NEVER “duh!!”)
- 5/8″ brad nails (or 3/4″ wood screws, if you prefer)
- One sheet of 1/2″ plywood. You don’t need the whole sheet, but you do need the full 8′ length.
SAFETY TIP: Your circular saw is one of the most dangerous power tools in your arsenal. When accidents happen, they usually happen fast and without warning– and more often than not, the damage is bad. The most frequent and dangerous blunder is binding the blade in a cut. This can happen when the saw blade is set too deep and more of the blade is exposed while cutting. The saw blade jumps up and kick back at you. It also happens when you’re cutting a long board or large sheet of plywood in half without the proper support. To prevent this, make sure the cut-off piece is free to drop or move away from the blade. This will eradicate any chance of binding and make your cuts safer.
1. Cutting the Fence Board
First, make sure the plywood you’ve got has at least one perfectly straight factory edge. You can tell by looking down the full 8-foot length of the board. If it looks straight, it should be straight enough to use. Mark the straight factory edge to keep track of it throughout the project. Nothing can drive you as crazy as forgetting which one it is. Lay the plywood down on the sawhorses to work. Cut a small piece off of the long direction, about a 3”-wide piece. Cut it as straight as you can, but it doesn’t have to be exact.
The main thing to keep track of here is the plywood’s factory edge. It’s the right edge in the above photo.
2. Cutting the Base
Because the factory edge has been verified as straight, it’s the most important part of the track build– but it’s only half of the saw’s guide. We still need a base for it to ride on. So, use the factory edge as a guide and clamp it on both sides to the rest of the plywood to saw off another strip. This time, it should be around 9” wide.
With the first strip clamped down and ready to be used as a reference fence for the circular saw, you might notice there’s some flex in the middle of the panel. To prevent this, clamp a piece of scrap wood in the center of the plywood on the opposite side of the first strip. This should prevent the first strip from flexing.
Then, with the saw tracking against the factory edge of the first strip, cut the 9” wide base strip (photo immediately above).
3. Putting It Together
Here’s where measurements might differ a little from saw to saw. You may have to adjust your dimensions as needed. With the circular saw blade resting against an edge of the plywood, measure the distance from the furthest edge of the circular saw base plate to the blade. Here it’s 3-3/4″, but, as mentioned, your measurement may be different (top photo above)
The first strip with the factory edge will be glued and nailed to the wider base strip, but the factory edge needs to be just a little further from one edge of the base strip than the distance from the blade of the circular saw to the furthest edge of the saw base plate. So, here it was set at close to 4” on both sides, and the base strip was marked (middle photo above).
After adding glue to the smaller strip, nail it to the base strip, ensuring it is on the reference lines from the previous step.
4. The Zero Clearance Line
The precision of the jig comes from this important step. Once the smaller strip is secure and the glue dried, make a cut referencing against the factory edge of the smaller strip. This establishes a “zero clearance line” for where the circular saw will cut every time you use the track.
Step 5: Enjoy Perfectly Straight Cuts
Having this 8′ track is incredibly handy for cutting sheet material, but it can be unwieldly when you need to make smaller precision cuts. For this reason, you may want to make another 8′ track and cut it into 5′ and 3′ sections.
Even the best carpenter can’t do good work with a dull blade. And besides making lousy cuts, a dull blade is dangerous. Dull blades can heat up and warp or bind, and they tend to climb out of the cut. But how do you know if your blade is too dull? The best indicator is how the blade cuts. If you have to muscle your way through the cut, your blade is dull. A sharp blade will glide through even the toughest wood. Burn marks and rough cuts are other signs of a dull blade. When it’s time to get your replacement, we recommend a plywood blade with at least 140 teeth like this:
You can find these and other quality woodworking tools at Harbor Freight Tools, at great, low prices!