High Alternate Top Bevel blades are a modification of the ATB design. You may find them labeled as HiATB, HATB or High ATB as well. Regardless of the specific labeling of the blade, they are all essentially the same. The major difference between HiATB and ATB blades is that the bevel angle on the HiATB blades is significantly increased to anywhere from 25 degrees to 38 degrees. This increases the effect of the ATB teeth, at the cost of making the blade more easily damaged and quicker to dull. Most commonly zero or negatively slanted hook angle on HiATB saw blade helps to inhibit self-feeding. It usually ranges from -5° to 2°.
These saw blades have been designed specifically for cutting high grade engineered wood sheet products, such as cabinet grade plywood, luan plywood and phenolic plywood. The increased bevel angle increases the effect of scoring the surface, over and above that which is encountered with ATB blades. This is especially critical when cutting across the grain of the outer veneer layer, as these types of woods are typically used for cabinetwork and furniture, where finish is critical. HiATB makes extra smooth crosscuts. HiATB blades are also excellent for cutting laminates, for the same reason that they work well with cabinet grade plywood. Laminates chip and crack extremely easily, which the high bevel angle of the HiATB teeth helps to overcome. Always support any laminate extremely well when cutting, as the weight of the material is enough to cause it to crack on the edge of a saw table.
Typically, HiATB saw blades have between 34 to 96 teeth, alternating left and right, as with ATB blades. This makes them a combination blade, which is necessary for cutting plywood and other engineered sheet goods. As with any type of plywood, one is both ripping and crosscutting at the same time, in the alternate layers of the wood product. For smoothest results, one should use at HiATB blade with the maximum number of teeth available. With higher tooth counts, each tooth is taking a smaller byte out of the wood, reducing the chance of splintering. While the higher tooth count makes for a slower cut, with more heat buildup, it is a worthwhile tradeoff to ensure a quality finish on the cut.
Of all the circular saw blade designs, HiATB become dull the fastest and are the hardest to sharpen. Most experienced cabinetmakers don’t even try and have them sharpened, preferring to replace the blades. This is due to the difficulty encountered in sharpening this tooth geometry. It’s recommended to use HiATB for special use only; a material is less resistant to wear when it’s pointed like on these blades. Good coating can greatly improve the durability of such blade.