1. SAFETY PRECAUTIONS WHEN WORKING
WITH POWER SAWS
• Mount or remove work only when the saw is stopped and is
M t k l h th i t d di
raised well above the vise.
• Clamp the w/p securely on both sides of the blade if possible
possible.
• Use only blades that are in good condition and which are the
correct kind for the material being cut
cut.
• Operate the machine at a cutting speed and feed rate that does
not strain the machine or the blade.
• Keep hands away from the saw blade when it is running.
• Stand out of line with the blade when starting an abrasive
cutoff saw.
• Do t bend
D not b d over in front of a power hacksaw frame when the
i f t f h k f h th ENG
I NE ER I NG
T
AL
EC
MECH NIC
HNOLOGY
m/c is running.
A
MET
1 E N
T
D
P A
R T ME

2. SAWING MACHINE TYPES
Classification :
1. Reciprocating : Power hacksaws
2. Circular saw: Cold saw & abrasive
3. Band saw: Horizontal, vertical cutoff
I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
2 E N
T
D
P A
R T ME

3. Reciprocating Sawing Machines: Hacksaws :
# Used primarily for cutting to length metal of various sizes & shapes.
# These sawing m/c vary in design from light-duty to heavy-duty m/c.
g y g g y y y
# Actual cutting takes place in only one direction and the saw blade
is lifted slightly on the return stroke.
I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
3
Fig. Reciprocating power hacksaw E N
T
D
P A
R T ME

4. Circular Sawing Machines :
Commonly known as cold sawing machines.
Work pieces are clamped in a vise or fixture, one or more pieces at a
time.
The circular blade is mounted on a power driven arbor & rotated
through the cut.
Abrasive discs are also used for cutting off stock.
An abrasive disc is a thin, flexible grinding wheel.
The disc is mounted on a machine that can be adapted for either wet
or dry cutting.
I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
4 E N
T
D
P A
R T ME

5. Horizontal Band saws :
Are available in a wide variety of types and sizes.
It has a flexible, "endless" blade which cuts continuously in one
direction. The thin blade travels over the rims of two pulley.
di ti Th thi bl d t l th i ft ll
The saw frame, hinged at the motor end, has two pulley wheels over
which the continuous blade passes.
passes
The step pulleys are used to vary the speed of the continuous blade.
The roller guide brackets provide rigidity for a section of the blade
and prevent it from wandering and twisting.
I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
5 E N
T
D
P A
R T ME

6. The blade tension handle is used to adjust the tension on the
saw blade.
The vise mounted on the table can be adjusted to hold various
sizes of w/p.
BLADE
TENSION
I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
6 Fig. The main parts of horizontal Bandsaw E N
T
D
P A
R T ME

7. Sawing Hints :
# Never attempt to mount, measure or remove work unless the saw
is stopped.
# Guard long material at both ends to prevent anyone from coming
in
i contact with it.
t t ith it
# Use cutting fluid, whenever possible, to help prolong the life of
the saw blade and improve the cutting action
action.
# When sawing thin pieces, hold the material flat on the vise to
prevent the saw teeth from breaking
breaking.
# Use caution when applying extra pressure to the saw frame as
this generally causes work to be cut out of square.
g y q
# When several pieces of the same length are required, set the
stop gauge saws.
I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
7 E N
T
D
P A
R T ME

8. CONTOUR BANDSAW PARTS AND
ACCESSORIES
The contour bandsaw is generally fabricated from steel.
g y
The contour bandsaws has many advantages in the metal-cutting
trade.
I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
8 E N
T
D
P A
R T ME

9. I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
9 E N
T
Contour bandsaw parts
D
P A
R T ME

10. Contour Bandsaw Parts and Operations
The basic parts are (1) base (2) column (3) head
Base :
The base of the contour bandsaw supports the column and houses
the assembly that provides the drive for the blade.
Column :
The column supports the head, the left-hand blade guard, welding
unit, and th variable-speed handwheel
it d the i bl dh d h l
Head :
The parts found in the head of a saw are generally used to guide
or support the saw band.
I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
10 E N
T
D
P A
R T ME

11. Bandsaw Operations
(a) Notching : Sections of metal removed
in one piece
(b) Slotting : Quick and accurate without
expensive fixtures
i fi t
(c) Angular cutting : Work clamped at any
angle & table may be tilted
(d) Radius cutting : Internal or external
contours
I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
11 E N
T
D
P A
R T ME

12. Horizontal Bandsaw Blades
High speed tungsten and high speed molybdenum steel.
CONTOUR BAND SAW BLADES
Three types of saw blades generally used are
(1) Carbon alloy
Carbon-alloy,
(2) High-speed steel,
(3) Carbide-tipped blades.
I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
12 E N
T
D
P A
R T ME

13. Tooth Forms
Three types of tooth forms:
(a).
(a) Precision or Regular Tooth - This is the most generally
used . It is used when a fine finish and an accurate cut are
required.
(b). Buttress or Skip Tooth - This tooth form is similar to the
precision tooth; however, the teeth are spaced farther apart
Used on thick work sections and on deep cuts in soft material.
material
(c). Claw or Hook Tooth –
It has the same general application as the buttress-tooth form.
buttress tooth form
It is faster cutting and longer lasting than the buttress tooth,
but will not produce smooth finish.
I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
13 E N
T
D
P A
R T ME

14. I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
14 E N
T
D
P A
R T ME

15. PITCH
Numbers of teeth per standard reference
length
Inch standard = No. teeth/inch
Metric standard = No. teeth/25 mm
Thickness of material to be cut determines
pitch of blade to use.
use
Coarse: thick, Fine: thin
I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
15 E N
T
D
P A
R T ME

16. There are three common set patterns
(1) W
Wavy :
– Alternate arrangement of several teeth to right
and l ft
d left.
– Used to cut tubes & light sheet metal.
(2) Straight : One tooth left & the other right.
Used for brass, copper & plastic
(3) Raker :
– Three teeth in sequence left, right, & straight.
– Used for steel & cast iron ENG
I NE ER I NG
T
AL
EC
MECH NIC
HNOLOGY
A
MET
16 E N
T
D
P A
R T ME

17. I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
17 E N
T
D
P A
R T ME

18. Blade Length
2* CD+3.14*D
CD= CENTER DISTANCE
D= DIA OF PULLEY
I NE ER I NG
ENG T
AL
EC
MECH NIC
HNOLOGY
A
MET
18 E N
T
D
P A
R T ME