Work Hardening and The 701 Series of high performance bandsaw blade that ends at 4-6 TPI. Why does this blade end at 4-6 TPI?
The difference between the 3-4 and the 4-6 TPI from 5-8, 6-10, and 10-14 variable tooth pitch is the rake angle on the teeth.
For the 3-4 and 4-6 variable tooth pitch, both blades have ten° of positive rake teeth, which means that the tooth angles move forward — in the direction of the cutting action.
The 5-8, 6-10, and the 10-14 TPI all have a zero° rake angle on the teeth, which means that the harder the blade is dug into the material, the more damage it can cause to the work piece.
A perfect example of the 3-4 and 4-6 TPI is a to think about a cat’s claw. The curvature of the nails.
3-4 and 4-6 variable tooth pitch dig down into the work when cutting high resistance steels like stainless steel. T1, D2 — where the teeth have to pull out the chips. If the chips are not pulled out of the material, it can cause the material to work harden.
Work hardening develops in the metal as a result of 1.) cold working, 2.) dull bandsaw teeth, 3.) excessive band speed, and 4.) too light a feeding force.
It would be difficult to pull out the chips if the steel is already work hardened. That is why the 701 Series of high performance bandsaw blade only have up to a 4-6 variable tooth pitch: to make sure that the chips are pulled out of the material being cut in order to avoid work hardening.