These are some of the most commonly asked band saw blade
determines the choice between bi-metal and carbon blades?
Basically, material and desired performance. Most tougher materials, such as
stainless steel, either can't be cut by carbon blades, or take so much longer
and use up so many blades that the cost is ridiculous. On the other hand, very
abrasive materials, such as fiberglass, wear the teeth of any blade - bi-metal
or carbon - so quickly that an economy carbon blade with lowest cost should be
used. Bi-metal blades should always be used on automatic machines and in any
operation where the requirement for high performance is paramount. For tool and
die contouring, narrow width bi-metal blades outperform carbon blades up to 10
should tooth pitch be selected?
basic rule is to keep 6-12 teeth in the material for bi-metal blades,6-18
teeth for carbon blades. Fewer teeth than this range risks tooth strippage,
more teeth risks both strippage and gullet clogging. The range can be achieved
through the correct combination of tooth pitch and proper vise loading.
is a variable pitch blade, and when is it used?
blade with teeth which vary in gullet depth, set angle and number per inch
(pitch). Less vibration, less noise and smoother cuts are the benefits.
Variable pitch blades are particularly beneficial for cutting tubing,
structurals and other interrupted surfaces which tend to induce strong
vibration forces. When combined with positive rake, the variable pitch blade
has no equal for faster work penetration and increased sawing productivity.
what hardness do various materials become nonmachineable with bi-metal blades?
depends on the grade. Although we have used saw blades to cut metal with a
hardness as high as "Rockwell 47, in general the practical limit is Rc40. Above
that, the blade may saw the material, but blade life will be severely
is the best way to determine speed and feed?
charts are usually a good guide to select starting speed. Feed controls vary
widely from machine to machine (some are calibrated in pounds, others in
arbitrary scales of number). Therefore, after break-in (see next question),
chips are the best guide to correct feed and speed: Powdery? Increase feed.
(Powdery chips are O.K. when cutting certain cast irons and D-2.) Thick,
tightly wound? Increase speed. Hot, purple-blue? Decrease speed. Chips should
be nicely curled, silvery in color and warm but not hot - to the touch.
is break-in so important, and how is it done?
brand new blade has extremely sharp points on the teeth. If brought to the work
surface under normal feed pressure, without break-in, these points would rip
off, leaving jagged-edged teeth that would wear faster and cut rougher.
Break-in always involves very light feed pressure at the start, with full
normal pressure achieved gradually. A blade should always be broken in on the
same material it will be cutting. The number of cuts (square inches of
material) before reaching full normal feed pressure varies according to the
type of material being cut.
do some blades break when there is obviously plenty of life left in them?
There are two possible explanations. One is that the machine is out of
adjustment - wheels worn or out of alignment, guides not aligned or incorrectly
spaced, blade tension too high or too low. The other explanation has to do with
machine design in relation to the blade being used. The wheel diameter may
simply be too small for the blade, and/or the guides can't be moved far enough
from the wheels, causing accelerated blade fatigue.
important are the chip brushes on a saw machine?
important. Their purpose is to remove chips from the gullets of the blade and
thus keep them off the wheel surfaces and out of the wheel bearings thereby
prolonging the life of these machine components. Furthermore, if the teeth
return to the cut with chips in the gullets, there is increased likelihood of
tooth strippage. With clean teeth, you get better penetration and less tooth