Machinery's Handbook, 31st Edition
GRINDING WHEEL SAFETY 1313 Special Speeds: Continuing progress in grinding methods has led to the recognition of certain advantages that can result from operating grinding wheels above, sometimes even higher than twice, the speeds considered earlier as the safe limits of grinding wheel opera tions. Advantages from the application of high speed grinding are limited to specific pro cesses, but the Standard admits, and offers code regulations for the use of wheels at special high speeds. These regulations define the structural requirements of the grinding machine and the responsibilities of the grinding wheel manufacturers, as well as of the users. High speed grinding should not be applied unless the machines, particularly guards, spindle assemblies, and drive motors, are suitable for such methods. Also, appropriate grinding wheels expressly made for special high speeds must be used and, of course, the maximum operating speeds indicated on the wheel’s tag must never be exceeded. Portable Grinders.— The above discussed rules and regulations, devised primarily for stationary grinding machines apply also to portable grinders. In addition, the details of various other regulations, specially applicable to different types of portable grinders are discussed in the Standard, which should be consulted, particularly for safe applications of portable grinding machines.
Table 1. Maximum Peripheral Speeds for Grinding Wheels (Based on ANSI 7.1-2017) Maximum Operating Speeds Depending on Strength of Bond
Inorganic Bonds sfpm m/min
Organic Bonds sfpm m/min
Classification No and Types of Wheels a Straight wheels—Type 1, except classifi- cations 6, 9, 11, and 12, 13 and 14 below Recessed Wheels—Types 5 and 7 Type 20, 21, 22, 23, 24, 25, 26 Taper Side Wheels—Type 4 b Dish wheels—Type 12 Saucer wheels—Type 13 Cones and plugs—Types 16, 17, 18, 19 Cylinder wheels—Type 2 Segments
1
5500–8500 1675–2590 6500–9500 1980–2895
5000–6500 1525–1980 6500–9500 1980–2895 5000–6000 1525–1830 5000–7000 1525–2135 4500–6000 1370–1830 6000–8500 1830–2590 4500–6500 1370–1980 6000–9500 1830–2895 5500–6500 1675–1980 5500–8500 1675–2590
2
3 Cup shape tool grinding wheels—Types 6 and 11 (for fixed base machines) 4 Cup shape snagging wheels—Types 6 and 11 (for portable machines) 5 Abrasive disks and Cylinder Type Discs Solid and Segmental 6 Reinforced wheels—except cutting-off wheels (depending on diameter and thickness)
…
… 9500–16000 2895–4875
Type 1 wheels for Bench and Pedestal Grinders, Types 1, 5 and 7 also in certain sizes for surface grinders Diamond and cubic boron nitride wheels Metal bond Steel centered cutting off Cutting-off wheels—Maximum 4-inch diameter (including reinforced organic) Cutting-off wheels—Maximum 16-inch diameter (including reinforced organic) Cutting-off wheels—Larger than 16-inch diameter (incl. reinforced organic) Non-Reinforced All Diameters Snagging Wheels 16 inch or larger, (including reinforced organic)—Used on swing frame grinders Snagging Wheels 16 inch or larger, (including reinforced organic)—Used on semi-automatic snagging grinders
7
5500–7550 1675–2300 6500–9500 1980–2895
to 6500 … to 16000
to 1980 to 3660 to 4875
to 9500 … to 16000
to 2895 … to 4875
8
… … … …
… 14200–20000 4330–6100 … 9500–16000 2895–4875 … 9500–14200 2895–4330 … 9500–14200 2895–4330
9
10 Thread and Flute Grinding Wheels 11 Crankshaft and Camshaft Grinding Wheels
8000–12000 2440–3660 10000–12000 3050–3660 8500–12000 2590–3660 6500–9500 1980–2895
…
… 12500
3810
12
…
… 16500
5030
13 Internal Wheels—Type 1 and 4, Maximum diameter 6 inch
5500–8500 1675–2590 6500–9500 1980–2895
14 Mounted Wheels
10000
3050
10000
3050
a See Table 1a and Table 1b starting on pages 1284. b Non-standard shape. For snagging wheels, 16 inches and larger—Type 1, internal wheels— Types 1 and 5, and mounted wheels, see ANSI B7.1–2017. Under no conditions should a wheel be operated faster than the maximum operating speed established by the manufacturer. Values in this table are for general information only.
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