Millwright Section 2: Grinders Flashcards
When grinding what safety equipment should you wear?
Safety glasses AND a face shield
What is considered “hand grinding machines”
Bench or pedestal grinder, where the work is held and guided by hand
What is the typical speed of a bench grinder?
1750 rpm
What are two advantages of a side wheel grinder
The grinding face is flat, and the angle of the work rest to the face of the wheel does not change with wear
What is the most common abrasive in grinding wheels?
Aluminum oxide, aluminum oxide makes up 75% of all grinding wheels
What is silicon carbide used for?
Grinding high density materials such as, cemented carbide, stone, and ceramic
What is cubic boron nitride used for?
Grinding space age material
What is “hardness”
The ability of a material to scratch or penetrate another material
What is heat resistance?
The ability of a material to withstand the heat of grinding with out becoming dull
What is “toughness”
The ability of a material to resist impact and pressures created during grinding
What is “friability”
The ability of a material to fracture under stress along certain cleavage lines so as the cutting edges become dull, part of the grain breaks off and presents new material
What is the designated letter for a “vitrified” bond
“V” and they are used In 50% of all wheel and are used for speeds up to 6500 rpm
What is the designated letter for a “resinoid” bond
“B” and they are used in 33% of all wheels and are good for rpm from 9500 to 1600
What is the designated letter for “rubber”
“R” and they are good up to 16000 rpm
What should you set the gap at between your grinding wheel and tool rest?
1/16”
What is the maximum gap allowed between a grinding wheel and its tool rest?
1/8”
What distance distance from the wheel should the spark guard be adjusted from the wheel?
1/16” to 1/4”
What is a good way of checking for cracks in a grinding wheel?
Do a ring test
What is a blotter on a grinding disc?
A blotter is a peace of paper on the side of the grinding wheel land has all the information of the wheel on it.
What does it mean when you “dress” a grinding wheel?
You’re removing the top layer of dull abrasive particles to expose fresh ones beneath
Flanges should be at least ____ the size of the grinding wheel
1/3
