Grinders

Question 1

wheel guards on bench grinders should be be angled

Answer 1

30-45 degrees past vertical

Question 2

the nut on the left hand side of a grinder has a ____ hand thread

Answer 2

left

Question 3

the ability of a material to scratch of penetrate another material

Answer 3

hardness

Question 4

the ability of material to withstand heat of grinding without becoming dull

Answer 4

heat resistance

Question 5

the ability of material to resist impact and pressures created during grinding

Answer 5

toughness

Question 6

the ability of material to fracture under stress along certain cleavage lines

Answer 6

friability

Question 7

abrasive used for 75% of grinding, suitable for general work on all steels and ferrous metals except cast iron

Answer 7

aluminum oxide

Question 8

abrasive used for high density materials such as cemented carbides, ceramics and stone
also used for low tensile and non ferrous metals

Answer 8

silicon carbide

Question 9

what are the 3 grades (colors) of aluminum oxide grinding disc from strongest to weakest

Answer 9

grey-general purpose
light grey
white

Question 10

what are the 2 grades of silicon carbide grinding disc

Answer 10

green-cemented carbides, ceramics, other hard material

black-cast iron and non ferrous metals

Question 11

what are 3 bonds of grinding disc

Answer 11

vitrified
resinoid
rubber

Question 12

bond used for 50% of all wheels produced, used for speeds up to 6500 rpm

Answer 12

vitrified

Question 13

bond used in 33% of all wheels, used for rpm of 9500-16,000 rpm

Answer 13

resinoid

Question 14

bond used for thin cut off wheel because of its strength and ability to withstand shock, used for up to speeds of 16,000 rpm

Answer 14

rubber

Question 15

what are 6 markings on grinding wheels

Answer 15

abrasive type
grain size
grade
structure or density
bond type
manufacture record

Question 16

the piece of paper attached to side of grinding wheel, purpose is to protect flange from abrasive grit and compensate for uneven surface

Answer 16

blotter wheels

Question 17

flanges on grinding wheel should be sized

Answer 17

1/3 of the wheel

Question 18

dressing of a wheel should be performed under what 2 conditions

Answer 18

glazed- when abrasive becomes dull the wheel has a glazed appearance
loaded-the particle become jammed with the material being ground

Question 19

what are 4 types of dressers/truing

Answer 19

mechanical
abrasive stick
abrasive wheel
diamond dresser

Question 20

the action used restore the shape of a wheel and makes the outer surface concentric with the bore

Answer 20

truing a wheel

Question 21

wheel used to polish work pieces to a high lustre, made and charged with fine abrasive such as a polishing rouge

Answer 21

buffing wheel

Question 22

wheel consist of coated abrasives attached to a hub, used for light finishing, especially inside a bore

Answer 22

flap wheel

Question 23

wheel coated with abrasive used for light finishing, deburring and chamfering

Answer 23

sanding disc

Question 24

grit size coarse, medium, fine, very fine

Answer 24

10/30/70/220