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Grade
: It indicates the strength of the bond witch hold abrasive.
Soft: A to H
Medium: I to P
Hard: Q to Z
Bond
B: Resinoid
BF: Resinoid reinforced
E: Shellac
O: Oxychloride
R: Rubber
RF: Rubber reinforced
S: Silicate
V: Vitrified
FACTORS AFFECTING WHEEL SELECTION
The material to be ground and its hardness
ABRASIVE: Aluminium oxide for steel and steel alloys. Silicon carbide for cast
iron, non-ferrous and non-metallics.
·
GRIT SIZE: Fine grit for brittle materials.
Coarse grit for ductile materials.
·
GRADE: Hard grade for soft materials. Soft
grade for hard materials.
The amount of stock to be removed and the finish required
·
GRIT SIZE: Coarse grit for rapid stock removal as in rough grinding. Fine grit
for high finishing.
·
BOND : Vitrified for precision cutting. Resinoid or Rubber
for high speed cutting.
Wet or dry
GRADE: Wet grinding, as a rule, permits use of wheels at least one grade
harder than that of dry grinding without danger of burning the work.
The wheel speed
·
BOND: Standard vitrified wheels are not exceeding 2,000rpm, for higher
speeds are up to 3,600rpm. Standard organic bonded wheels (Resinoid, Rubber
or Epoxy) are used for most applications over 2,000rpm up to 6,000rpm.
·
NOTE: Do not exceed the safe operating speed shown on a wheel tag.
The contact area of grinding
·
GRIT SIZE: Coarse grit for large contact area. Fine grit for small contact area.
GRADE: The smaller contact area, the harder wheel.