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Saw blade teeth for circular saws and their most common combinations
ATB, HATB, HiATB, FTG, H-ATB, WZ, HATB, Hi-ATB, FZ, High-ATB, FA, TCG, FAS, TZ, ATBR, HLTCG, TR-F …
Obscure? Certainly, but you can also come across such labels and yes, it can give you a headache. In the following text, we will explain how to navigate in this confusing world of labels.
First of all, it must be said that until recently we only knew all-metal steel discs made mainly of chrome-vanadium steel. The body of the disc and its teeth were made of the same material. They dulled quickly, but we could sharpen them almost indefinitely. The width of the teeth and body was the same. To this day, they are mainly used for cutting contaminated construction wood and firewood.
hard metal inserts, referred to as HM / HW / TC, TCT and the like , are "rushing" to the fore . The teeth, fixed around the circumference of the body of the disc, are made of hard metal plates made of tungsten carbide . They have different geometries, are installed in different numbers and in different combinations, have different front and back angles... All this affects the quality of the cut and the purpose of use. Compared to all-metal discs, such discs retain their cutting properties significantly longer. However, it must also be said that although they are very hard, they are also fragile. Therefore, their teeth are usually protected, for example with a silicone ring. These teeth can also be ground, but not nearly as many times as all-metal teeth.
The basic four groups of teeth
At first glance, we classify the difficult labels into four groups.
fig. 1 ATB teeth
Alternating oblique teeth
The most common designation: ATB ( Alternate Top Bevel ) or WZ ( Wechsel Zahn ).
ATB teeth have a bevel from the upper, outer part of the tooth downwards, to the opposite side of the saw blade. The bevel angle is between 10 and 20 degrees and is the same for both teeth. The teeth are located alternately on the right and left, around the entire circumference of the disc.
A 20-degree bevel will provide a cleaner cut than a 10-degree bevel. ATB teeth, especially those with a larger number, are best suited for cross cuts in wood. It is therefore true that the larger the angle, the cleaner the cut, but the teeth are dulled sooner and the cut is slower.
Application: universal in soft and hard wood, wood fiber materials, veneered plywood, etc. The greater the number of teeth, the cleaner the cut, and the more beautiful the cross cuts.
fig. 2 Common tooth bevel angles ATB
fig. 3 Hi-ATB teeth : bevel angle 25-38
A subgroup of ATB teeth are alternately inclined teeth with a large bevel - more than 25 degrees. They are designated as Hi-ATB ( High ATB, HATB, Hi-ATB , Hi /ATB, H-ATB...).
They are optimized for making the cleanest and most perfect cuts. They are mostly produced with a higher number of teeth. However, thin and sharp tips wear out faster, so Hi-ATB toothed discs have a shorter lifespan than other types of teeth. And they need a powerful machine – a large number of teeth creates a higher resistance when cutting. Application: excellent cutting properties, especially in materials that are sensitive to the cleanliness of the cut, e.g. laminates, veneers and plywood. They are also great for very fine cuts in hardwood.
Flat teeth
The most common designation: FTG - Flat Top Grind or FZ - Flach Zahn.
They enable fast and efficient cuts, are durable and have a long service life. The disadvantage is that the cut is not pretty and causes the fibers to tear (e.g. in wood), so discs with FTG teeth are not used for cross cuts, nor for cutting where the appearance of the cut is important. They are the only teeth that leave a perfectly flat kerf bottom when cutting and are ideal for such applications. Also for this reason, we often find them in combination with other types of teeth. They act as a chisel that cleans the inner edges of the groove and levels the bottom of the cut.
Application: for fast cutting of wood along the grain of the wood and for applications where we need a perfectly flat bottom of the cut.
fig. 4 FTG teeth shape
fig. 5 Flat beveled teeth
Flat beveled teeth
The most common designation: FAS or FA
The usual chamfer of the outer edges is 30 - one edge is always beveled alternately. A disc with such teeth has a high resistance to foreign bodies in the cut material, e.g. nails, concrete remains, etc.
Application: on construction sites for cutting construction wood, formwork and chipboard, with a suitable combination of the number of teeth, considering the diameter of the disc, together with the angle of the face and back of the tooth, it is used for cutting steel materials.
Trapezoid teeth
The most common designation: TCG- Triple-Chip Grind or TZ – Trapeze Zahn
The four most used teeth are closed by trapezoidal teeth. They are trapezoidal in shape, usually with a bevel of 45 degrees on both sides.
Use: especially in combination with flat teeth.
We meet the mentioned types of teeth most often. The rest are just combinations of these types.
fig. 6 Trapezoid tooth
The most common combinations of teeth
fig. 7 ATBR teeth
Alternately slanted and flat teeth
They should be marked with a combination of letters according to the types of individual teeth, i.e. ATB + FTG, or WZ+FZ, but this is not the case. They are labeled ATBR ( Alternate Top Bevel with Raker ), i.e. "Alternative upper bevel with rake". We will immediately explain the justification of this name.
A combination of four alternating beveled teeth ATB and one flat tooth FTG is more commonly used. This fifth tooth in the series is referred to as a rake - this is because it "cleans up" after the previous four teeth.
Its flat upper edges are perpendicular to the body of the disc and it works in the notch like a chisel. It cuts out of the groove what the previous teeth left there. She cleans.
Application: for fast and clean cuts with clean edges in soft and hard wood, wooden beams and chipboards, optimized for transverse cuts. They also work well for longitudinal cuts, so we consider them a good all-purpose tooth design.
Trapezoidal and flat teeth
The most common designation: HLTCG ( High-Low Triple Chip Grind ) or TR-F (Trapeze – Flat)
Trapezoidal and flat teeth are placed alternately around the circumference of the disc, while the flat tooth is placed slightly lower. The role of the trapezoidal tooth is to roughen the cut, the following flat tooth – again in the function of a “rake” – cleans the cut. The result of this combination is a durable and stable blade with low tooth resistance when cutting, very little edge pull-out and quick chip release. The combination is suitable for cutting materials with a solid surface, as well as for cutting ferrous and non-ferrous metals.
Use: glued materials, laminated chipboards, plastics, hard wood, but also steel, copper or aluminum.
fig. 8 HLTCG teeth
Conclusion
The stated rules and principles are also valid for other types of teeth that we may encounter in practice. By understanding them, we can better imagine what happens during the cutting process and it will not be a problem for us to start a possible discussion about teeth with the seller behind the counter. Let's check the shape and placement of the teeth on the new wheel as well. Especially with those for manual circular saws, we will need a magnifying glass - the teeth are so small that we may not always be able to identify them well with the naked eye. And this knowledge comes in handy even when we have several used discs, but lack information on what kind of cutting they are suitable for.
Sources:
HERMAN internal technical and training materials
https://www.woodcraft.com/blog_entries/choosing-the-right-table-saw-blades
https://expertdie.com/all-about-saw-blades
https://df.tuzvo.sk/sites/default/files/10-1-13-siklienka-kminiak-argay_1_0_0_0_0_0_0.pdf
Ing. Herman Nagypál
I graduated from a military school. I learned to work with tools and equipment as a child with my father on the construction of our family house. I test each of our new products personally - with my own hands in my well-equipped workshop. In my spare time, I study trends in the field and like to try competitive products. Some of them make me laugh, and some of them make me wonder (that someone got caught and bought it), but some are really good. Almost like ours 😊.
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