How to choose the right saw blade for a reciprocating saw

The reciprocating saw is still an underappreciated, very specific tool, originally developed for demolition and rescue work. Today, thanks to various saw blades, it is used for many purposes in building construction and renovation. It is an invaluable helper when cutting atypical materials, such as large-diameter pipes and tubes, where other tools struggle to cope.

In principle, it is a saw with a reciprocating motion, where the cutting effect is achieved by pushing and pulling the saw blade. It is designed to be used in vertical positions as well. At its base, it has a shoe (footplate) that rests against the cut surface during cutting and prevents the saw from pushing away from the cut or pulling towards it during movement.

A reciprocating saw blade is, at first (but really only at first) glance, a simple product. In reality, it is a complex set of combinations of raw materials, processing technology, shapes, sizes, and tooth arrangements, as well as the shape and size of the blade body.

This article is not for those who prune branches in the garden with a reciprocating saw. It is mainly for builders, heating engineers, and window fitters who can utilize the advantages of the reciprocating saw in combination with suitable saw blades to their full extent.

Material composition and application of reciprocating saw blades

The raw material from which the saw blade is made is key information for choosing the material you can cut. On reciprocating saw blades, you can find designations such as HCS, Cr-V, BiM, HM, TC, TCC, TCT, and similar.

Saw blades for cutting wood

HCS (High alloyed Carbon Steel) is high-alloy carbon steel. Saw blades marked this way are suitable exclusively for cutting wood and similar materials. Their main advantage is an affordable price. This category of materials also includes chrome-vanadium steel (marked CV, CrV, Cr-V, etc.). Essentially, it is a steel alloy containing chromium (0.80 – 1.10%) and vanadium (0.18%). Chromium adds hardness and strength, and the combination with vanadium makes the steel more suitable for hardening. Both of these materials (HCS and CrV) are used to manufacture saw blades for cutting wood and the like.

Saw blades for cutting metal

BiM (bimetal) means two metals – two strips of metal with different properties joined mechanically, as shown in Fig. 1.

Fig. 1. Bimetal - two strips of metal with different properties

For saw blades, a combination of spring steel is used with a cutting part made of HSS – High-Speed Steel. HSS is a material used to manufacture tools for metal machining (for example, the well-known HSS metal drill bits). Such a saw blade is very flexible; it returns to its original position after bending and allows the cutting metal materials – and of course, if the teeth are large enough, wood as well. The disadvantage is the higher price.

Saw blades for cutting construction materials

HM, TC, TCC, TCT - these are all saw blades that have a cutting part made of carbide (hard metal). Note – only the cutting part is made of carbide; the body of the saw blade is made of HCS or CrV materials.

The cutting part can be fitted with carbide tips that are brazed on, or carbide grains of the appropriate grit are applied to the cutting part of the saw blade electrolytically. They are used for cutting construction materials, such as plasterboard, paving, tiles, bricks, aerated concrete, and some even for cutting cast iron.

Tab. 1. Saw blade materials and their use

However, simply discussing raw materials is not enough. A very important factor is the teeth of the saw blades – their size, the distance between them, and their set.

Cutting geometry of saw blade teeth

With reciprocating saws, we encounter four types of tooth cutting geometry in practice: MS, MWS, CS, and CT.
MS (Milled Set) – Milled, set teeth

Fig. 2. Milled, set teeth

The teeth are bent alternately to the sides. The saw blade engages during both the upward and downward strokes, which makes the cut rough. With Cr-V or HCS saw blades with such tooth setting, wood fibers tend to tear; with bimetal saw blades, this arrangement is mainly used for cutting thick-walled materials.

MWS(Milled Wavy Set) – Milled teeth, wavy set

Fig. 3. Milled teeth with wavy set

Cutting takes place over the entire surface of the tooth. The difference compared to MS is only in the shape of the teeth. The cut is relatively fine, and this is used mainly with bimetal saw blades designed for cutting thin-walled metal materials.

CS (Crossground Set) – Cross-ground, set teeth

Fig. 4. Cross-ground, set teeth

Wood fibers are cut by the oblique position of the teeth. Teeth with such an arrangement and grinding provide the blade with a very high cutting speed. Used especially for aggressive wood cutting, as well as for cutting live wood – pruning.

CT (Crossground Tapered) – Cross-ground, tapered teeth

Fig. 5. Cross-ground, tapered teeth

Wood fibers are cut thanks to the shape of the ground back and sides of the teeth, arranged in a conical shape in the cut. The cut is very clean, especially when the teeth are diamond-ground.

Size and spacing of teeth

The larger and sparser the teeth, the rougher the cut. The smaller and denser the teeth, the smoother the cut.

However, you would look for tooth size as a parameter in vain. It is simple: the teeth on the saw blade follow each other in such density as their size allows; therefore, the larger the teeth, the greater the distance between them, and vice versa.

The distance between teeth is called tooth pitch, and it is the measurement from the tip of one tooth to the tip of the adjacent tooth. It is given in millimeters, for example, 8.5 mm – one tooth every 8.5 mm (sparse teeth, rough cut), or 2.5 mm – one tooth every 2.5 mm (dense teeth – fine cut), or even 1.0 mm, which is a very fine cut.

On the packaging of saw blades, near these data, there is usually another numerical figure regarding the teeth followed by three letters: TPI (or t.p.i.).

TPI – what is it?

TPI is a peculiar designation – you would look for it in vain among SI units. However, it is also very practical, and once we master it, we can forget about the distance given in millimeters.

We often encounter the inch ("cól") even today. Tell a carpenter that the thickness of a board is 1 inch, and he immediately knows what it is. Inch = 25.4 mm.

TPI (Teeth Per Inch) means the number of teeth per "inch", and the explanation is clear from the example shown in the following image:

Fig. 6. Distance between teeth - converting TPI to millimeters

14 TPI means 14 teeth over a length of one inch, so the distance between teeth is 25.4 / 14 = 1.8 mm.

Shape of the saw blade

From the shape of the saw blade body, we can largely determine its purpose.

A narrow blade allows for cutting curves (Fig. 7), a short and rigid beak-shaped blade (Fig. 8) is also suitable for plunge cuts, and a blade of uniform width along its entire length is suitable for straight cuts (Fig. 9).

Fig. 7. Saw blade with a narrow body

Fig. 8. Saw blade with a short, beak-shaped body

Fig. 9. Saw blade with uniform width

Thickness of the cut material

The thickness of the cut material is determined by the length of the saw blade's toothed section.

Fig. 10. Cutting a wooden beam

When cutting metal profiles, it is necessary to take into account the wall thickness of the profile and choose not only an appropriate saw blade length but also toothing suitable for the given wall thickness of the cut profile material.

Fig. 11. Cutting a metal profile

Conclusion

We now know that to perform a sufficiently wide range of jobs, you need the right saw blades. However, a tool with sufficient power input is particularly important. For mains-powered (220V) reciprocating saws, we recommend a minimum power input of 1200W; for cordless ones, a power supply of at least 18V/4Ah batteries, and if possible, a brushless motor, which has higher efficiency than brushed motors.

Sources:
HERMAN internal technical and training materials
https://sk.wikipedia.org/wiki/Legovanie
https://en.wikipedia.org/wiki/Chromium-vanadium_steel
https://sk.wikipedia.org/wiki/R%C3%BDchlorezn%C3%A1_oce%C4%BE
https://sk.wikipedia.org/wiki/Kalenie
https://en.wikipedia.org/wiki/Reciprocating_saw

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 😊.