GRAIN
Grinding wheel grain: abrasive granule size.
| Extra-Large |
Large |
Medium Large |
Medium |
Medium Fine |
Fine |
Extra-Fine |
| 8 |
14 |
24 |
46 |
80
|
120 |
220 |
| 10 |
16 |
30 |
54 |
90 |
150 |
240 |
| 12 |
20 |
36 |
60 |
100 |
180 |
280 |
HARDNESS
Grinding wheel hardness: resistance required by the bead to detach itself from the agglomerative base.
| Very Soft |
Soft |
Medium |
Hard |
Very Hard |
| E |
H |
L |
P
|
T |
| F |
I |
M |
Q |
U |
| G |
J |
N |
R |
V |
| |
K |
O |
S |
Z |
STRUCTURE
Grinding wheel structure: spacing or distance among the various abrasive granules.
| Very Closed |
Closed |
Medium |
Open |
Porous |
Super Porous |
| 0 |
3 |
5 |
8 |
10
|
12 |
| 1 |
4 |
6 |
9 |
11 |
14 |
| 2 |
|
7 |
|
|
16 |
BONDING AGENT
Its purpose is to assemble the different granules in order to constitute a compact abrasive.
There are two main forms of bonding agent:
a) "V" (vetrified) or inorganic (clay, kaolin, feldspar, silicate, etc.).
b) "B" (resinoid) or organic (syntetic resins, bakelite, shellac, rubber, etc.).
EXEMPLE OF MARKING ON A THE BEST® GRINDING WHEEL
| 1. Diameter
2. Thickness
3. Hole
4. Abrasive
5. Grain
6. Hardness
7. Structure
8. Bonding agent
9. Peripheral speed
10. Revolutions per minute (rpm)
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