9
Parker Hannifin Corporation
Tube Fittings Division
Columbus, OH
FluidConnectors
Bulletin 4390-974250
Cut 250 Saw Use and Maintenance Manual
9.2 — Choosing the blade
First of all, the pitch of the teeth must be chosen, according to
these criteria:
• Parts with a thin and/or variable section such as profiles,
pipes and plate, need close teeth, so that the number of
teeth used simultaneously in cutting is from 3 to 6;
• Parts with large transverse sections and solid sections need
widely spaced teeth to allow for the greater volume of the
shavings and better tooth penetration;
• Parts made of soft material or plastic (light alloys, mild bronze,
teflon, wood, etc.) also require widely spaced teeth.
9.3 — Teeth pitch
As already stated, this depends on the following factors:
• Hardness of the material
• Dimensions of the section
• Thickness of the wall
9.4 — Cutting and advance speed
The cutting speed (m/min) and the advance speed (cm
2
/min =
area travelled by the blade teeth when removing shavings) are
limited by the heat build up at the tips of the teeth.
• The cutting speed is subordinate to the resistance of the
material (R = N/mm
2
), to its hardness (HRC) and to the di-
mensions of the widest section.
• Too high an advance speed (= blade descent) tends to cause
the blade to deviate from the ideal cutting path, producing
non rectilinear cuts on both the vertical and the horizontal
plane.
9.5 — Breaking in the blade
When cutting for the first time, it is good practice to break in
the tool making a series of cuts at a low advance speed
(= 30-35 cm
2
/min on material of average dimensions with re-
spect to the cutting capacity and solid section of normal steel
with R = 410-510 N/mm
2
),
generously spraying the cutting area
with lubricating coolant.
S (MM)
PICTH
SHAPE
SPEED
up to 2
4 - 6
B
shaped
2
2 ÷ 5
8
C
solid
2
5 ÷ 10
8
C
solid
1
over 10
8
C
solid
1
up to 20
8
C
solid
1
20 ÷ 50
10
C
solid
1
S
S
S
9.6 — Type of blades
Blades differ in their constructive characteristics, such as:
• Tooth shape
• Tooth cutting angle
Tooth shape
The profile of the teeth depends on the size, shape and thick-
ness of the section to be cut, either straight or at an angle. It
may also vary according to the pitch, but not so distinctly as to
make this an element for classification.
• Fine teeth are to be chosen for cutting small sections with a
profiled shape and tubular sections with thin walls (2-5 mm
depending on the material).
• Large teeth are suitable for cutting medium and large solid
sections or fairly thick profiled or tubular sections (over 5
mm).
“A” toothing:
“AW” toothing:
Normal fine toothing
Fine toothing with
alternate side rake
“B” toothing:
“BW” toothing:
Normal large toothing with
Large toothing with
or without shaving breaking
alternate side rake
incision
“C (HZ)” toothing:
Added toothing:
Large toothing with roughing
Blades made in this way
tooth with rake on both sides,
are used for cutting non-
alternating with a finishing
ferrous metals, such as
tooth without rake. The
light alloys and plastics,
roughing tooth is 0.15-
and in woodworking. The
0.30 mm higher.
teeth are hard metal
(HM) plates brazed onto
the body of the blade;
there are various types
and shapes and, consid
ering the vastness of the
field.
Tooth cutting angle
Each tooth has two cutting angles:
•
α
αα
αα
: front rake angle
•
γγγγγ
: rear rake angle
