What You Should Know About Band Saw Blades
Are you plagued by breaking band saw blades? Band saw blades break when you are not treating them correctly. This unfortunate event often occurs due to not choosing the correct blade, not breaking in a new blade, or not using the right band speed. Here we will give some pointers on these topics.
Choosing the Right Bandsaw Blade
Firstly, let's delve into the important factors for selecting the right bandsaw blade for your needs:
Carbide Blades vs. Bi-metal Blades
Carbide blades provide resistance to high heat and stand up well while cutting materials as they resist abrasion. For the most part, carbide blades cost less and handle aluminum, copper, brass, and bronze aptly. Bi-metal blades stand up better to cutting at high speeds and therefore can handle super alloys. Bi-metal blades cost more than carbide ones, but they will perform up to five times longer.
Blade Thickness and Width
You need to consult the manual for your bandsaw to determine the right blade thickness and width. The needed length correlates with the wheel diameter.
Understanding Tooth Pitch (TPI)
Pitch refers to the distance from the tip of one tooth to the next one. Small pitch means more teeth are close together while large pitch means the teeth are spaced farther away from each other. TPI (teeth per inch) refers to how many teeth are in an area. It is important to have at least 3 TPI in the material you are cutting. 6TPI and 10TPI are popular as they cut most materials smoothly. 14 TPI works beautifully with thinner materials like plastics and non-ferrous metals.
Deciphering Tooth Rake
Tooth rake refers to the angle of the hook. A positive hook angle allows for aggressive cutting as the blade grabs deep into the material and cuts faster. A low or negative hook angle controls the feed rate and prevents the blade from climbing the material being cut. The low or negative hook angle provides a smoother cut requiring little to no sanding.
Breaking in a New Blade
New blades need to be broken in before attending their first job. To start, reduce the feed pressure to half of the normal band speed. Do this for the first fifty inches of material being cut (150 inches if you are cutting low or mild carbon steel).
If you have issues with inaccurate cuts, it’s probably due to an improperly broken in blade. Other reasons for inaccurate cuts include: dull blades, the guide arms stationed too far apart or not properly aligned, damaged roller or carbide guides, a heavy feed rate, a slow speed, or the vise grip being out of square. Dull teeth can be caused by an improperly broken-in blade, inconsistent flow, improper speeds, coolant concentration, or incorrect tooth pitch. All in all, it takes some practice to use and care for band saw blades. Don't hesitate to ask us if you need some advice.
Calculating Your Band Speed
Do you need to know what your correct band speed is? You need to learn your SFPM (surface feet per minute) in order to calculate your band speed. Go to http://vintagemachinery.org/math/sfpm.aspx to calculate this easily. You will need your motor RPM, your motor pulley diameter, wheel pulley diameter, and band wheel diameter.
In conclusion, bandsaw blades requires attention to proper break-in techniques and understanding various factors such as blade type, thickness, width, tooth pitch, and tooth rake. With the right knowledge and a bit of practice, you can ensure that your bandsaw blades perform at their best, providing accurate and efficient cuts for your projects.