Arbor Hole Out-Of-Round
CAUSE: Saw arbor badly worn due to blade being improperly seated.
REMEDY: Be certain the blade is properly seated on the arbor before
tightening flange.
CAUSE: Blade flanges not properly tightened permitting blade
to rotate on shaft.
REMEDY: Always wrench tighten arbor nut - never hand tighten.
Always use hex nuts - never use wing nuts.
CAUSE: Blade flanges or arbor shaft worn and not providing proper
blade support. REMEDY: Check blade flanges or arbor shaft for
wear. Both flanges should be no less than that recommended by
the manufacturer. Replace worn parts.
NOTE: If the out-of-round condition of the blade is not too serious,
return the blade to the factory for possible repair.
Eccentricity
CAUSE: The bond is too hard for the materi-al being cut. The
hard bond remains the dia-monds which begin to round off; causing
the blade to become dull. Instead of cutting, the blade begins
to "pound", causing the blade to wear out-of-round.
REMEDY: Change to a softer bond which will wear away more readily
allowing the dull diamonds to be released and sharp, new cutting
edges to become exposed.
CAUSE: The saw blade shaft may have a groove scored in it, caused
by a blade spinning between the flanges. A new blade, installed
on the arbor shaft, will seat into the groove, and immediately
run eccentrically when the saw starts.
REMEDY: Replace the worn shaft.
CAUSE: If the blade shaft bearings are worn, the shaft and mandrel
will run eccentric causing the blade to wear out-of--round. This
happens most often with con-crete saws when proper lubrication
of the bearings is neglected.
REMEDY: Install new blade shaft bearings. In some cases it might
also be necessary to replace the blade shaft, if it is worn or
out of alignment.
CAUSE: Blade shaft bearings may be worn. If they are, the shaft
and mandrel will run eccentric causing the blade to wear out-of-round.
This happens most often with concrete saws when proper lubrication
of the bearings is neglected.
REMEDY: Install new blade shaft bearings. In some cases it might
also be necessary to replace the blade shaft, if it is worn or
out of alignment.
Loss of Tension
CAUSE: Blade being used on misaligned saw.
REMEDY: Check for proper saw alignment.
CAUSE: Blade is excessively hard for the material being cut,
creating stress on the steel centre.
REMEDY: Make certain blade is correct for material being cut.
(Consult manufacturer's recommendation chart or see your dealer.)
CAUSE: Material slippage causing blade to twist and become kinked
or bent.
REMEDY: Maintain tight grip on material while sawing.
GAUSE: Utilizing blade flanges that are undersized or not the
same diameter, creating uneven pressure on the centre.
REMEDY: Make certain blade flanges are proper size and identical
diameter, minimum 3-7/8"; 4-1/2" on concrete saws; 6"
minimum on dia-mond blades that are 30" diameter and larger.
CAUSE: Blade being used at improper RPM.
REMEDY: Make certain blade shaft is turning at the proper RPM
by using a tachometer. This is especially important with concrete
saws.
CAUSE: Blade improperly mounted on arbor shoulder becomes bent
when flanges are tightened.
REMEDY: Hold blade securely on arbor shoulder until outside flange
and nut are firmly tightened.
Cracked Cores
CAUSE: Blade is too hard for material being cut.
REMEDY: Use correct blade with softer bond.
CAUSE: Excessive cutting pressure, or jamming or twisting the
blade in the cut can cause the blade core to bend or flex. When
subjected to extreme stress and metal fatigue, the blade's steel
core will eventually crack.
REMEDY: The saw operator should use steady, even in feed pressure,
and be careful not to twist or jam the blade in the cut.
CAUSE: Overheating through inadequate water supply or improper
use of dry-cutting blades.
REMEDY: Use adequate water to cool wetcutting diamond blades (for
example, 2-5 gallons per minute for concrete saws). Allow adequate
air flow around dry cutting diamond blades to prevent overheating.
NEVER USE A BLADE WITH A CRACKED CORE!
Cracked Segments
CAUSE: Blade is too hard for the material being cut.
REMEDY: Use correct blade with softer bond.
Blade Won't Cut
CAUSE: Blade is too hard for materials being cut. Examples: Block
or General Purpose Blade being used for extended period on hard
brick. Asphalt blade being used to cut hard concrete.
REMEDY: Consult dealer or manufacturer for proper blade to cut
materials on job.
CAUSE: Insufficient power to permit blade to cut properly. (Loose
V-belts, low voltage, motor lacks horsepower).
REMEDY: Check belts, voltage, horsepower.
CAUSE: Blade has become dull because of continuous use on fairly
hard or vitrified material.
REMEDY: Dress with abrasive material until diamonds become exposed
again. (This may be necessary occasionally but if dullness occurs
too often, the blade is probably too hard for the material.)
CAUSE: Blade segments appear to still have plenty of life but
blade won't cut.
REMEDY: Some harder bonded blades de-signed for abrasive materials
require a non-diamond bearing section at the base of the diamond
segment for better adherence to the steel core. A blade used to
this stage has worn out in the normal manner and should be re-placed.
Excessive Wear
CAUSE: Using the wrong blade on highly abrasive material. (ExampIe:
Glazed tile blade on concrete block).
REMEDY: Consult the dealer or manufacturer for the proper blade
specification for abrasive material.
CAUSE: Lack of sufficient coolant to the blade. Often detected
by excessive wear in the centre of the segment. (NOTE: In both
above cases, diamonds will usually be highly exposed).
REMEDY: Clean up water system. Make certain water pump is functioning
properly.
CAUSE: Wearing out-of-round accelerates wear. Usually can be
caused by bad bearings, worn shaft, or using a blade too hard
for the materials being cut.
REMEDY: Check bearings and arbor. If worn; replace with new parts
before installing another blade.
CAUSE: Insufficient power caused by loose Vbelts, inadequate
voltage, or improper RPM's.
REMEDY: Tighten belts (TAUT) Replace worn belts. Check voltage.
Use proper size extension cord.
Undercutting
CAUSE: Undercutting is a condition in which the steel centre
wears faster than the diamond segment, especially in the areas
where the segment and core are joined. The condition is caused
by highly abrasive material grinding against the blade during
the sawing operation.
Usually materials containing sand are responsible for this condition.
(See section on SEGMENT LOSS).
REMEDY: The flow of swarf (abrasive cuttings) must be distributed
over a wider area, away from the critical seg-ment area. Many
times this can be accomplished by using Polyarc seg-ments or other
types of undercut pro-tectors, specially positioned around the
steel centre to change the pattern of constant abrasion. Although
suc-cessful in most cases, undercut protec-tors do not provide
100% protection.
Segment Loss
CAUSE: The material slips during cutting which twists or jams
the segments loose.
REMEDY: HoId the material securely while cutting.
CAUSE: BIade is too hard for the material it is cutting, causing
excessive dullness which causes the segment to pound off, or fatigue.
REMEDY: Use a softer blade specification.
CAUSE: Worn blade flanges fail to provide proper support causing
the blade to deflect.
REMEDY: Replace both blade flanges.
CAUSE: Out-of-round blade rotation resulting in pounding, caused
by worn arbor or bad bearings in the shaft.
REMDY: Replace worn arbor and/or bearings.
CAUSE: Overheating. Usually easily detected by bluish colour
on steel centre, generally confined to the area where the segment
was lost.
REMEDY: Check the water system for blocked water passages. Test
pump to see if it is functioning. For dry cutting it may be necessary
to make shallower cuts and allow the blade to run free every few
minutes to let the air cool it.
REPAIR NOTE: It is possible to replace two or three missing diamond
segments providing the steel centre is not cracked or undercut
badly. If many segments are missing, or if there is less than
50% of blade life remaining, repairing the diamond blade may not
be economical.
Be certain to eliminate mechanical or operational problems before
installing replacement blades.
Uneven Segment Wear
CAUSE: Segments worn on one side re-ducing side clearance. Usually
caused by misalignment of the saw or a lack of sufficient water
on both sides of the blade.
REMEDY: Check saw alignment; clean water system, making certain
that water is properly applied to the leading edge of the blade
flanges. Check to see if pump is supplying sufficient, even water.
(See RAPID WEAR section).
CAUSE: Blade is worn out-of-round due to bad bearings, worn arbor
or excessive dulling condition. (See sec-tion on EXCESSIVE WEAR).
REMEDY: Replace bearings or worn ar-bor as required.
TRADE
