A reciprocating saw is one of the most useful power tools you’ll ever own for construction, renovation and demolition work. To get the most out of your saw, you need to use the right blade for the material and situation you’re dealing with.
Photos by Rob Brown
You’ll find job-specific reciprocating (recip) saw blades for just about everything – cutting nail-free wood, nail-embedded wood, non-ferrous and ferrous metal, masonry, plaster and drywall, fibre cement, rigid foam, and fibreglass. There are also specialty blades for making flush cuts, removing grout, scraping, sanding, pruning trees and shrubs, and removing paint and rust.
This article looks at some of the key features you need to know about when selecting recip blades for nail-free wood, nail-embedded wood and metal, the three materials you’re most likely to encounter.
The shank
The shank locks into a recip saw’s blade clamp. Fortunately, all recip blades have the same size shank, which means any recip blade will fit into any recip saw. Recip saws won’t accept jigsaw blades.
Universal Shank – The universal shank will fit any brand of recip saw. The blade can also be used while rotated 180° in the chuck. This will allow the user to cut upwards or downwards, depending on the situation.
Blade design
Recip blades for wood or metal can have straight, curved or sloped backs. All can be used for making straight cuts, though wider straight-backed blades provide greater stability for straight cutting, particularly in nail-free wood. Blades for metal are usually straight backed. Curved and sloped blades are a better choice for plunge and general-purpose cutting, such as for working on drywall and hardboard. Manufacturers have also come up with different tip designs to facilitate plunge cutting.
Blade Shapes – Narrow sloped blades are better for making plunge cuts, while parallel backed blades excel at making straight cuts. Blades with straight backs and narrower blades (bottom) are better at cutting curves.
Recip blades are from 3″ to 12″ long, with 6″ and 9″ the most popular lengths. Shorter blades vibrate less, making them a better choice when you want straight, square, clean cuts. For flush cutting, where you may need to bend the blade, choose a blade that’s 9″ or 12″ long. However, when making plunge cuts use a short blade or you’ll invariably bend the blade. In general, the best way to avoid blade wobble is to use a blade that’s only a few inches longer than the stock you’re cutting.
Flexibility for Flush Cuts – Although most reciprocating blades will bend, thinner blades are less likely to break and are great for making flush cuts.
Blade teeth configuration
The teeth on a recip blade are measured in teeth per inch (TPI), and can range from 3 to 24 TPI.
Blades for nail-free wood are usually in the 3 to 6 TPI range. For a somewhat cleaner cut choose a 6 to 12 TPI blade. Blades specifically designed for nail-embedded wood will generally have slightly more TPI.
General purpose or demolition blades often have a variable tooth configuration that makes the blade suitable for cutting nail-embedded wood and metal, depending on how you position the blade. Coarser teeth for cutting wood and nail-embedded wood are at the front of the blade, while finer teeth for metal are close to the shank.
Variable TPI Blades – Some blades have teeth with a certain TPI towards the shank and a different TPI towards the tip. This Diablo blade is 14 TPI near the shank and 8 TPI at its tip.
Ferrous metal places a huge strain on blades so it’s important to match the thickness of the stock to the right TPI for the blade. For cutting metal up to about 1/2″ use an 8 to 10 TPI blade. For metal up to 5/16″ a 14 to 18 TPI blade works well, and for thin metal up to around 3/16″ use a 20 to 24 TPI blade.
Recip blades cut in one direction – on the pull stroke. Fleam ground blades (which have two cutting edges per tooth) cut on both the pull and push stroke, which makes them cut faster and cleaner. These blades are great for cutting nail-free wood or pruning trees and shrubs.
TPI is Important – Different sizes of teeth help determine what a blade is best suited to cut. From bottom to top, 20 TPI, 14 TPI, 6 TPI and 3 TPI.
Orbital Action
If your reciprocating saw has an orbital action setting, use it when cutting nail-free or nail-embedded wood. Your blade will cut faster and last longer. In orbital mode the blade not only moves up and down but thrusts forward at a slight angle. The trade-off is a slightly rougher cut and sometimes a less vertical cut. However, avoid using it when cutting metal, especially when you want to make clean, precise cuts. For metal it’s better to lubricate the blade – stick wax when cutting non-ferrous metal and cutting oil for ferrous metal.
Blade thickness
A thicker blade will resist binding, be less prone to bending and vibrate less. The downside is that they cut more slowly and typically cost a bit more. High carbon steel blades for wood tend to be .05″ thick. Bi-metal blades are generally in the .035″ range, while demolition blades and those for cutting metal up to about 1/2″ thick are generally upwards of .062″.
Blade coating
Some manufacturers coat their blades to reduce friction and heat buildup and improve wear resistance. Some employ a non-stick Teflon-type coating, while others use a thin metallic coating, such as titanium nitrate. These anti-stick coatings eventually wear off; sooner when cutting metal rather than wood.
Cut in Three Directions
There are a few unusual blade designs on the market. The Spyder 3×3 blade features a variable tooth configuration with the teeth running completely around the edge of the blade, enabling you to cut in three directions – straight, plunge and reverse cuts. While it’s not a one-blade-does-all, it’s a handy-when-needed blade that gives you a bit more versatility. The DEWALT Breakaway, which comes in 6″ and 9″ lengths, is a two-blades-in-one design that enables you to reinsert the unused part of a broken blade back into your recip saw.
Fleam Ground Blades – Some reciprocating saws have a fleam grind, which means their teeth are ground to cut in both a push and pull motion. These types of blades are generally for raw wood, and don’t work well on metal or other materials.
Carbide Teeth – Tiny carbide teeth are fastened to the body of some blades making them very durable.
Diamond Blades – Small diamond particles can be attached to some blades. Because there are no true teeth, the diamonds will abrade the material rather than cut it, leaving a very fine dust in the air. Though not made for wood, these types of blades can be used on a lot of other materials.
Blade Materials – Like everything in life, there are pros and cons to various blade materials. Whether it’s how long its teeth remain sharp, how flexible the blade is, or how expensive a blade is, you always have to weigh the pros and cons for your situation. This blade is stamped with “HCS” for high carbon steel.
These are the least expensive blades you can buy; both blade and teeth are made of HCS. Because the blades are fairly flexible, they’re not overly prone to breaking, though the teeth deteriorate quickly. These blades are best used for cutting clean softwood, hardboard and plastics, and not recommended for demolition work or cutting metal. The blades can have variable-sized teeth and gullets for faster chip removal.
HSS is much more durable and heat-resistant than HCS so these blades will last appreciably longer. However, they aren’t as flexible as HCS blades making them somewhat more prone to breaking. They’re a better choice when cutting both non-ferrous (aluminum, copper, lead, zinc and tin) and ferrous (mild steel, carbon steel, cast iron and wrought iron) metal.
Blades that combine a HCS body and HSS teeth are known as bi-metal blades. The blade is both flexible and break-resistant while the teeth have enough hardness and durability for general duty work, which makes them the most popular recip blades. Some manufacturers coat either the whole blade or blade teeth with titanium or cobalt-steel alloy to provide better heat- and wear-resistance and extend blade life.
Blades marketed as “general purpose” or “demolition” tend to have thicker profiles and hardened teeth. Some have variable teeth spacing. These blades are best suited for more extended use in nail-embedded wood and both non-ferrous and ferrous metal. There are also Fire & Rescue blades, which also have thicker blades and often a curved blade design for faster cutting.
These are the toughest, longest-lasting blades you can get. The blade is typically bi-metal, with heat-resistant and impact-resistant tungsten carbide or titanium carbide teeth. They’re a better choice when you have a lot of nail-embedded wood or metal to cut (including stainless steel and high strength alloys). They cost more than standard bi-metal blades but last considerably longer, giving you a much better return on investment.
Use these blades for masonry, ceramic tile, fibre cement, cast iron and the like. Just remember: they don’t cut, they grind. Wear a respirator to avoid breathing in the fine particulate material. Diamond blades cut faster and last longer than carbide blades, but cost more.
While you may be more familiar with CMT as a maker of premium quality table saw blades and router bits, they also manufacture a line of HCS blades for wood (3, 5, 6 and 6/10 TPI), and BIM blades for wood and metal (6, 10, 8/12 and 10/4 TPI). There is also a BIM rescue/demolition blade (5/8 TPI) and a 6 TPI carbide blade. Blade lengths include the standard 6″, 9″ and 12″ plus some 8″. CMT blades features a non-stick Orange Shield coating that helps to keep the blade running cool and reduces pitch build-up and corrosion.
This Canadian company has an extensive range of blades. Blades come in Industrial (premium) and Professional (contractor) grades. The EAB blades are the company’s flagship line of exchangeable blades for wood (HCS in 3 TPI and BIM in 3 and 6 TPI), wood and metal (BIM in 10/14 TPI), and metal (BIM in 10, 14, 18 and 24 TPI). There are also blades for pruning (9″ BIM in 5 TPI), plaster (6″ BIM in 6 TPI) and fire/rescue (9″ BIM in 10/14 TPI). There is also a Stay Sharp line consisting of HCS (3 and 5 TPI), BIM for wood (6 TPI), BIM for wood and metal (10/14 TPI), BIM for metal (10, 14, 18, and 24 TPI), and carbide grit edge blades. In the Razor Back demolition line are both exchangeable and recyclable BIM blades (6 and 8/10 TPI) and exchangeable carbide blades (6 TPI).
With woodworkers and DIYers getting more environmentally conscious every day, it’s nice to see some companies catering to the current approach of ensuring a sustainable future. EAB, with their Exchange-A-Blade program, provides customers with savings once they return the used product. Norske, and their Trade-A-Blade system, provide credits towards future purchases for returning their products after use. These companies carry not only a wide range of reciprocating saw blades, but also an extensive selection of blades, bits, abrasives and much more. These services are convenient for customers while reducing waste and making better use of natural resources. Once these products are used and returned they’re either re-sharpened, if possible, or properly recycled. Visit ExchangeABlade.com and NorskeTools.com for more information on their systems.
Diablo has one of the largest selections of carbide blades. They manufacture their own high-density carbide from 5-micron carbide grain rather than the more typical 1-micron grain. For clean wood they have HCS (5 TPI) and carbide (3 TPI) blades, while for nail-embedded wood there are BIM (4/6 TPI) and carbide (5/7 TPI) blades. For general purpose (wood and metal) cutting there are BIM (10/14 TPI) and carbide (6/9 TPI) blades. When it comes to cutting metal, Diablo has BIM and carbide blades for thin (under 3/16″), medium (under 5/16″) and thick (under 1/2″) stock. You’ll also find a diamond grit blade for cast iron, fibre cement, masonry, and fibreglass, a carbide (32 TPI) blade for HVAC and ductwork, and a carbide (5 TPI) blade for scrolling and radius cutting. All Diablo blades have a Perma-SHIELD Non-Stick Coating.
The Milwaukee AX blades are for wood cutting – they come in BIM (5 TPI with a fang tip for plunge cutting), and carbide (3 TPI and 5 TPI) for either wood or nail-embedded wood. Most of these blades are available singly or in packs of 5, 10, 25 or 100 blades. Wrecker multi-material blades are for cutting nail-embedded wood, PVC / plastic and thick metal. They come in either BIM (with 7/11 TPI) or carbide (6 TPI with a fang tip). For cutting metal there are TORCH blades in BIM (10 to 24 TPI) and carbide (7 TPI) for both thick metal and cast iron. All Milwaukee blades are made in the U.S.
These German-made blades come in 7 BIM blade styles along with a tungsten carbide grit blade for cast iron and masonry and carbide (6 TPI) for hardy plank, pressure treated lumber, cement board and fibreglass. The BIM blades include a curved blade with wavy teeth set (18 TPI) for cutting metal, a demolition blade for wood (6 TPI) and a separate demolition blade for metal (10 TPI). Their blade for nail-embedded wood features a patented “M-Tooth” design that cuts on both the forward and backward stroke to deliver super quick cuts. They also offer a fire/rescue blade (6 TPI) and a pruning blade (3 TPI).
Metabo carries 5 and 6 TPI HCS blades for wood; 6 TPI BIM blades for nail-embedded wood; 10/14 TPI general purpose (wood and metal) BIM blades; 6 and 8/10 BIM demolition blades; and 10, 14, 18 and 24 TPI BIM blades for metal. They also have specialty carbide grit blades and carbide blades (2, 3, 6 and 18 TPI) for fibre cement and tile, along with a carbide blade (2 TPI) for brick.
Along with the six brands we’ve listed above, you’ll also find recip blades from a range of other companies, including Bosch, DeWALT, Imperial Blades, Irwin, Spyder, Lenox, Makita, MK Morse and Starrett.
Carl Duguay - [email protected]
Carl is a Victoria-based furniture maker and the web editor at Canadian Woodworking & Home Improvement.