A Rippin’ Good Time
We have blades that cut more efficiently and leave a better cut surface than ever. And this has led to the debate about the need for any blade beyond a good combination blade.
Tablesaw blade technology and CNC machining are bringing us blades we couldn’t have dreamed of a couple decades ago. Improved and ubiquitous, carbide teeth are not only better at shearing wood fibers but they also stay sharp longer and, with the increased accuracy of machining, allow tighter tolerances for consistent side relief angles and cutting angles. What does this all mean to the average woodworker? Well, we have blades that cut more efficiently and leave a better cut surface than ever. And this has led to the debate about the need for any blade beyond a good combination blade.
I’m a huge proponent of appropriate blades for specific needs. I will use my combination blade for general cutting on the tablesaw when I’m ripping thin (3/4 in. or thinner) stock or rough crosscutting stock, but when it’s time to rip heavy stock or to make precise, clean crosscuts, I change blades.
Ripping wood involves very different needs than crosscutting. When we rip wood, we cut parallel to the wood’s grain structure (lots of long, fibrous tubes), producing stringy sawdust that is easily compacted into blade-dragging and gullet-filling detritus. Large gullets between the teeth and larger side clearance angles on the teeth of a dedicated rip blade assure these strands of sheared wood can be evacuated quickly from the sawkerf and don’t end up packed in the blade. The drawback to a dedicated rip blade is a slightly rougher cut, but I’m going to be jointing the rips so it’s not a big deal.
You can see that the gullets on the 20-tooth rip blade on the bottom are significantly larger than the 40-tooth blade at top. And you can also see that there is a different geometry to the sharpening on the dedicated rip blade. This rip blade can hog its way through thick hardwood without breaking a sweat, yet it still leaves an acceptable surface. It will make your lower-horsepower saw a much better ripping machine.
On the other hand, if we compare the 40-tooth combo blade to an 80-tooth crosscut blade, we see a huge difference in the gullets: the crosscut blade has tiny cavities for sawdust removal.
Crosscutting shears across those pesky wood fibers and creates short, fragmented sawdust that is easy for a blade to evacuate. No packing the gullets here (unless you’re working with very resinous woods, then you’re sunk). The benefit of a dedicated crosscut blade is the silky-smooth surface it leaves on end grain and the minimal tearout on the side where the teeth exit the wood. The large number of teeth also makes trimming wood where the blade is not contained in a kerf easy, as there are always teeth involved in the cut, helping to eliminate blade distortion and vibration.
So my routine is to use a dedicated rip blade (20 to 24 teeth) for thick stock, a combo blade for general light-duty cutting, and a dedicated crosscut blade (60-plus teeth) for precision crosscuts.
Taking a few minutes to install the correct blade can save time, material, and frustration.
Do you change blades or just compromise?
If you have any questions that you’d like answered by Rollie, send them to TalkingTools@FineWoodworking.com.