There are many factors to consider when deciding which band saw blade is right for your project. Choosing the wrong blade can cause damage and be costly. Keep the following tips in mind to ensure a long-lasting, durable blade, all while staying safe.
Keep these top tips in mind, and you are sure to pick out the product best suited for each of your projects.
1. Blades and Materials
Consider a carbide-tipped blade or tungsten carbide for cutting large quantities of high-nickel-alloy steel. Carbide is recommended over high-speed steel because it offers more resistance to heat and the blades hold their edges longer than bimetal blades when cutting harder materials.
Use carbon band saw blades for:
Bimetal blade teeth are bonded to allow for a better combination of cutting speed and durability. Bimetal blades are more resistant to tooth stripping and can withstand high operating temperatures (1,000 degrees F). Some bimetals are heat treated or coated to provide strength and rigidity. These blades can withstand the punishment of cutting shapes and bundles, and possess the hardness for continuous use with solids and heavy-walled tubing.
Use bimetal band saw blades for:
2. What Blade Properties Are Important to Consider?
The following characteristics should be considered in choosing the right tool for the job and your pocketbook:
- Hardness: must be maintained at high heat levels
- Toughness: must prevent chipping or fracturing
- Wear resistance: must last an acceptable amount of time before replacement
- Purpose: must consider product to be cut (the right blade for the material)
Carbon steel may be the most traditional, general purpose and inexpensive material, but it is the least wear resistant. Bimetals are becoming far more common, and the tips are often upgraded to high speed steel for higher heat wear resistance, durability and increased hardness. Carbide tipped blades are the most expensive blades out there; however, they are also the hardest and most durable.
3. Choose the Correct Thickness and Width
Correct blade size is essential for optimal performance. Use your manual to choose the proper blade length. Blade lengths are specific to each band saw and the length is determined by the wheel diameter and the distance between those wheels.
For blade width, consider the maximum capacity of the band and the minimum radius to cut. The width of the blade should be the widest the machine permits (this ensures the blade does not break and will cut straight). For contour cutting, narrow the width to enable cutting the correct radius. The manufacturer’s instructions should also be consulted.
The diameter of the wheels and work to be done will dictate the requisite thickness of the blade. Thick blades can withstand more strain from straight cuts but will break easily from the resulting bending and twisting. Thinner blades are best for lighter work.
4. Consider Pitch and Tooth Rake
Thin materials will require a smaller pitch, finer spaced teeth (more teeth—closer together). Thicker materials will require a larger pitch, coarser spaced teeth (fewer teeth—further apart). The aim is to have a minimum of three teeth in a cut; six to twelve is optimal. Choose a coarser pitch for speed, but if finish is more important, consider a finer pitch.
Choose the proper tooth rake based on the material and shapes to be cut. A positive angle increases the tilt of the tooth face and is best-suited for heavy-wall tubing and thick solids. Straight or less positive rakes are preferred for bundle/structural cutting.
5. The Teeth: TPI, Types, Tooth Steps, and Stripping
Finish and feed rate are the key features when considering teeth per inch (TPI). Slower cuts generally require more teeth; faster cuts need fewer. Faster cuts will not be as smooth. A minimum of three teeth embedded in the cut at all times allows the blade to remain stable, maintain accuracy and do a better job.
Coarse tooth blades of 2–3 TPI should be used for re-sawing and thicker materials. For general wood cutting, a range of 4 TPI (coarse, fast cutting) to 14 TPI (slower, smoother cutting) is best. A 6–8 range is considered a good “general purpose” blade. A finer TPI (18–32) should be used for thinner metals and plastics under ¼ inch in size.
There are three main styles of teeth to consider: skip, hook and regular. Regular teeth are used for general applications and operate at a zero-degree/straight tooth rake. The deep gullets rake out chips. Regular blades should be used for thin materials and when a fine finish is desired.
Hook teeth are larger in size with deeper gullets. Hook teeth have a positive 10-degree angle (undercut face) which allows for more aggressive/forceful cutting. The gullets curl the chips and the angle of the tooth helps to dig in to the material. Generally, the hook tooth allows for faster feed rates. Use hook teeth for hardwood, plastics, thick wood and metal, especially for long cuts.
Skip teeth operate at a zero-degree tooth rake, making for a sharp angle at the tooth/gullet junction to break up chips and prevent clogging. The teeth are set wider than regular style. Use skip teeth to cut soft nonferrous metal, plastics, wood and other soft materials.
There are three general types of tooth sets: raker, alternate and wavy. The raker tooth set is used when cutting thick, solid metal sections (horizontal cut-off machines), contour cutting and re-sawing (vertical machines). The alternate set provides for faster, smoother cuts. Wavy set blades are made with smaller teeth and are recommended for cutting materials including but not limited to thin sections of metals, thin sheets and tubes/pipes.
Don’t overload the force on the blade. This will cause repeated impacts with the material (especially when cutting bundles or structural shapes). The force and repeated impacts will result in tooth stripping, one of the most common band saw issues.
6. Shoot for the Appropriate Set
Shoot for the appropriate set—optimal balance between sawdust and air occupying that space—when considering the area between the body of the blade and the material to be cut. The optimal set will be an 80:20 ratio (80 percent sawdust and 20 percent ejected). The sawdust should be warm, not hot and not cold.
7. Flutter Testing and De-tensioning
Fluttering is a method whereby, while the band saw is running, the user can correct the tension of the band saw. It may be necessary for the user to tweak the settings and adjustments in order to reduce/eliminate vibrations and ultimately achieve the optimal function of the blade.
Failure to de-tension can result in fatigue, blade memory, blade failure, the distortion of the crown, flattening (and thus hardening) of the drive tires, and stresses to the motor, drive pulleys and shaft V-belt. Always de-tension—completely relax—the blade when you are done cutting.
Never use water! Not on band saw blades or any blades for that matter. Water is not a lubricant; it will rust and damage the blade and the material being cut. Look for appropriate products on the market that are specifically designed to lubricate blades and other cutting tools. Make sure to choose a product that will not stain what is being cut.
9. Know your Surface Feet Per Minute
Surface feet per minute (SFM) allows selection of the proper speed for the material to be cut. Band saw blade manufacturers will provide a maximum SFM rating for their product. Consult your owner’s manual.
10. Other Variables to Consider
EQUIPMENT CONDITION AND TYPE
Keep your equipment well-maintained and vibration-free. You will be rewarded with improved accuracy and longer blade life. If you are seeing blade wear patterns, you may need to adjust the wheel or the guides may be worn.
Choose the right coolant for your applications to improve the cut and again, the life of your blades.
Develop these skills to ensure continued productivity:
- Ability to identify equipment problems and get assistance or service
- Ability to read the chips to determine if the blade/equipment are cutting properly
- Ability to observe the cut to ensure the downfeed is correct
- Ability to make different types of cuts when using a manual downfeed band saw
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