Bonded Abrasives

Grinding Wheel

Grinding Wheel is a most common used tool and is your Machine Tools's "teeth". It is important to select a right wheel for your right job and is helpful to minimize the cost and maximize the efficiency. How to select a correct wheel, must learn some info and symbol as below.

Wheel Grade

The GRADE means the relative power of the bond which holds abrasive grains in a wheel, and indicates the degree of difficulty for them to be pulled out by grinding stresses. The hardness of the work to be ground and the grinding condition determine the grade of a wheel.

Grade	Very Soft	Soft	Medium	Hard	Very Hard
Symbol	A, B, C ,D, E, F, G	H, I, J, K	L, M, N, O	P, Q, R, S	T, U, V, W, X, Z

Bond

The BOND, which holds the grain particles to a wheel has an important effect on the physical and chemical properties and the grinding ability of the wheel, and is to select according to the requirement on the job. We have three kind bonds of wheels, vitrified, resinoid and magnesite.

Bond	Symbol	Characteristics & Application
vitrified	V	It is of friability and stability, suitable for finishing and semi-finishing on cylindrical, internal, centerless and tool grinding machines, for off-hand grinding also.
resinoid	B	It is of high strength and used for common roughing, high speed grinding, steel snagging, cutting and etc.
magnesite	L	Usually used for grinding cutters and husking or polishing grains

Abrasives

The ABRASIVES plays the major role in grinding job. There are two main kinds of conventional abrasives, Fused Alumina & Silicon Carbide, to meet the properties of materials to be ground and user's requirements.

Abrasive	Symbol	Application
Brown Fused Alumina	A	For operations on metals of high tensile strength, such as carbon steel, common alloyed steel, cast iron ant etc
White Fused Alumina	WA	For finishing alloyed steel, hardened steel and toll steel
Rose Fused Alumina	GA	For tool and internal grinding or for precision and high finish surface grinding.
Black Silicon Carbide	C	For operations on metals and non-ferrous materials, such as brass, leather, hard rubber and etc..
Green Silicon Carbide	GC	For cemented carbide

Grit Size

The term of "GRIT SIZE" means the size of particles and is to choose depending on user's requirement of accuracy, surface finish of the work to be ground.

Grit Size	12#, 14#, 16#, 20#, 22#, 24#, 30#, 36#, 40#, 46#, 54#, 60#, 70#, 80#, 100#, 120# 150#, 180#, 220#, 240#, 280#, 320#
All grit size shown above is same as F-grit size of FEPA Standard

Structure

The grinding wheel consists of abrasive grains, bond and voids. Structure is the proportion by volume of these three elements and usually determined by the abrasive grain percentage.

open

mediem

dense

Symbol of Grinding Wheel Shape

See Dimension table (word installed / Acrobat Reader installed)

Formula of Marking a Wheel

The contents of the marking system are: abrasives, grit size, grade, bond shape and dimension, all denoted by symbols in the following order.

Abrasive	Grit Size	Grade	Bond	Wheel Shape	Dimensions
A, WA, GA, C, GC	36# - 320#	A - Z	V, B, L	See Dimension Table