When it comes to new tooling design and development, no one can accuse Freud Tools of laziness. If you follow news from or about the company, you’ll notice that their always working on some new carbide recipe, or redesigning the geometry of tooling that’s hasn’t really been improved upon for years. Not too long ago, for example, they successfully brought a number of novel ideas to the good old general purpose saw blade with their well received Premier Fusion Blade. Lately they’ve been at it again, this time with their new “Quadra-Cut” router bits.
The big news with the new Quadra-Cut bits isn’t so much that they’re founded on some radically new concept. More, they represent another example of the Freud knack for bringing together the best of existing technologies, throwing in a dash of their own appreciable ingenuity and well-know metallurgical prowess, and coming out with a combination that takes a tool that most of us thought was pretty much “done” one step further. In the case of Quadra-Cut router bits, the innovation has to do mainly with cutting geometry. Instead of the typical two cutter design, Quadra-Cut bits have four cutters, arranged so that two main blades perform an “up-cut” and two smaller ones perform a “down-cut”.
So, what does that mean, and why is it important? Up-cut and down-cut (or up-shear and down-shear) router bits are nothing new. The terminology simply means that instead of running parallel to the body and shank of the bit, the cutters of these two types of bits are angled. But this seemingly minor difference has a considerable impact on the way the bits perform. Up-shear and down-shear bits cut the surface of the stock with a slicing motion, instead of chopping straight into it. The result is less energy consumption, less vibration and, a cleaner cut.
Shear bits behave differently depending on whether they have an up-cut or a down-cut configuration. The down-shear of the flush trim bit you see on the left forces chips and shavings downward away from the router, and also has a tendency to pull the base of the router downward toward the material (as counterintuitive as that may sound). Both of these behaviors are desirable in many applications. When you're using a handheld router to make flush cuts along a pattern or straightedge, for example, the first keeps the work surface clear of debris, and the second makes it easier to keep the base of the router flat on the surface of the workpiece.
An up-cut orientation, on the other hand, propels chips and shavings upward out of the cut. Because of that, an up-cut bit is great for mortise work. An up-cut spiral bit - which is essentially a shear bit taken a step further – is the ideal choice for deep mortises. A solid carbide spiral bit makes smooth, fast work of cutting a deep mortise, while the up-cut oriented helix augers chips and shavings up out of the hole and keeps the mortise from getting packed with debris.
Up-shear and down-shear bits share one other, equally important quality: both leave one very clean edge one the surface of the material. Unlike a straight-fluted bit, a down-shear bit slices downward into the top surface of the material and as a result, leaves a crisp, chip and “fuzz”-free cut edge. Likewise, an up-cut bit – although it is less often the purpose of using one – leaves a similarly clean edge on the bottom side of the material.
Can you have the best of both worlds? In this case, yes, you can – thanks to “double compression” router bits. Spiral double compression bits combine both an up-cut and down-cut configuration, and are the most widely used of a variety of router bit. A double compression spiral bit is the ideal choice for edge trimming and cutouts in situations where both top and bottom edges of the material require a delicate touch. The solid carbide Freud bit pictured here will leave a near-perfect edge on both sides of virtually any routable material, including chip-prone laminates.
And now, with Freud’s new Quadra-Cut bits, you can have it both ways in a variety of profiles. Capitalizing on the virtues of the compression design, Quadra-Cut bits each have two large up-shear cutters that do the majority of the heavy lifting, and two smaller down-shear blades that just trim just a little bit of material off of top edge. The up-cut cutters do an excellent job of hogging out the bulk of the cut and moving debris up and away, and they also leave a characteristically smooth cut edge on the bottom edge of the cut. The two smaller cutters slice downward into the material, taking off just enough to ensure a crisp top edge, free of the too-familiar fringe of attached fibers that plague cross-grain cuts.
An incidental advantage of using Quadra-Cut bits is, of course, simply that are Freud bits. In other words, they’ve inherited all of the qualities that have made Freud a top choice all along: the cutters are made from Freud’s proprietary TiCo carbide and then attached to the bit using the company's sophisticated “tri-metal” brazing method. They all bear the famous red Perma-Shield non-stick coating, are computer balanced for reduced chatter, and feature large, anti-kickback bodies for added safety. All in all, we think it’s a great package, a great idea, and one of the best things to happen to router bits in a long, long time.