Blade Structure - Jet J-FK350-4 Operating Instructions And Parts Manual

13.5 Blade Structure

For non-ferrous metals, it is common to use
circular saws with brazed hard metal HM cutting
edge, consisting of a disc made of alloy tool steel
(71Cr1) on which the shape of the teeth and the
seats for the cutting edges are made of Widia K10.
These saws have shown excellent wear resistance
but low resistance to impact, which is in any case a
minor problem with non-ferrous materials.
Table 2
13.6 Types of Blades
The blades fitted to the J-FK350 have dimensions
350 x 32 x 2.5 mm and are of HM hard steel type
since the machine is to be used for cutting non-
ferrous materials. In addition to the size and pitch
of the teeth, however, the blades also have
different geometric characteristics in accordance
with their particular use:
tooth cutting angle – may be negative or positive
tooth sharpening – may be BW with an alternate
raked tooth or C with a roughing tooth raked on
both sides and a non-raked finishing tooth
tooth pitch – the distance between the crest of
one tooth and the crest of the next tooth (tooth
pitch = T)
13.7 Teeth Shape
"C" TYPE SHARPENING (HZ)
Coarse toothing with roughing tooth raked on both
sides and non-raked finishing tooth. The roughing
tooth is about 0.3 mm higher.
Coarse toothing with roughing tooth and finishing
tooth. Used in saws with pitch greater than or equal
to 5 mm for cutting ferrous and non-ferrous
materials with solid or solid-profiled
"BW" TYPE SHARPENING DIN 1838--UNI 4014
Coarse toothing with teeth alternately raked to the
right and left.
Toothing generally used on cutting-off machines for
cutting ferrous and alloy materials with tubular and
profiled sections.
POSITIVE AND NEGATIVE CUTTING ANGLES
The cutting angle may vary from positive to
negative depending on the cutting speed, the
profile and the type of material to be cut.
A positive angle determines better penetration of
the tool and hence lower shear stress and greater
ease of sliding for the swarf over the cutting edge.
On the other hand, the cutting edge has lower
mechanical resistance, so as the breaking load of
sections.
the material to be cut increases, the cutting angle
decreases from positive until it becomes negative
so as to offer a cutting edge with a larger resistant
section.
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Figure 14
Figure 15
Figure 16