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QUALITIES
PROPERTIES
PRODUCT
RANGE
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: hacksaw blades :
hand hacksaw - properties
 PROPER
SELECTION OF BLADE
COMMON
SAWING PROBLEMS
PROPER SELECTION OF BLADE
While selecting a blade “Three Teeth Rule” should be followed
and this requires that during cutting a minimum of three teeth be continuously
in contact with the work.
Thin Sections
Use a fine tooth blade or else metal wedges up between teeth, stripping
them off. If the section is too thin to follow, the “Three Teeth
Rule” use a very light steady stroke.
Thick Sections
Use a coarse tooth blade with heavy pressure. This gives greater pressure
per tooth and
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FEED
AND CHIP FORM
AIDS TO BETTER CUTTING
consequently a deeper cut. The larger space between teeth gives ample
chip clearance.
Hard Sections
Special care must be taken when cutting harder materials. It is better
in terms of blade life to use finer tooth blades, with a light pressure
and slower speed of cutting or else heat is built up rapidly on the
cutting edge causing the metal to soften even in the case of High Speed
Steel Blades. Faster speeds are permissible if a coolant is used.
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FEED AND CHIP
FORM
COMMON
SAWING PROBLEMS
AIDS
TO BETTER CUTTING
- Be sure that the teeth point away from the handle frame i.e. make
certain that they cut on
the forward stroke.
- Apply the correct tension to the blade.
- When sharp angles or else the “ Three Teeth Rule” is violated
for any blade used.
- Start the cut with the blade at a slight angle and with light pressure
gradually increasing the pressure as more teeth come in contact with
the job.
- If very thin section are to be cut, clamp
them between two pieces of wood and cut as a whole.
- For low alloy hand blades, the speed of cutting
should be approximately 55 strokes/ min.
- For High Speed Steel hand baldes, use a higher
speed approximately 65 strokes/min expect
when cutting tool steel, in which case the speed should never exceed
40 strokes/min.
- After starting the machine, lower the frame carefully and relieve
the weight (or reduce the feed)
for a few strokes. After cutting the first two or three sections check
that the tension is correct.
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