Machinery's Handbook, 31st Edition
740 V-Block Types The Grade B Type III shall be of fine grained cast steel and conform to the dimensions and tolerances defined in Table 8. The nominal dimensions referenced in Table 7 and Table 8 do not represent the full extent of options available. Tolerances are defined as the minimum acceptable. Higher accuracy V-blocks of the Type III Style 1 and 2 may be available. Table 7. Type III, Style 1 Quadruple V-Groove Block
Permitted Deviations (inch)
Parallelism of “V” to Base and Side 0.0003
Flatness of Working Faces
End/Side Square to Base
Parallelism of Opposite Faces
Grade
“V” Centrality
Matching Tolerance
Grade A 0.0001 Grade B 0.0004
0.0002 0.002
0.0002 0.001
0.0003 0.002
0.0002 0.001
0.002
Grade Characteristics Grade A • Steel alloy • Surface finish NTE 32 µ in • Material hardness 50–62 RC Grade B • Mild steel or high grade cast steel • Surface finish NTE 63 µ in • Material hardness 40–45 RC steel / 200–280 BHN cast steel Designating Size Nominal Dimensions (inch) Length Width Height Maximum Capacity 1 2.000 1.500 1.500 1.125 All dimensions in inches Type III, Style 2, Quadruple V-Block.— Type III, Style 2, Quadruple V-Block is de- signed for a robust precision support of the work piece. This style V-block is not furnished with clamp or yoke and may be made of either mild steel or fine grain cast steel. The Type III, Style 2 block may be designed with uniform V-groove capability or a range of capaci- ties. The tolerance of the Style 2 V-block will conform to those shown in Table 8, however the nominal dimensions and accuracies referenced in Table 8 do not represent the full extent of options available. Manufacturers’ tolerances are always applied. Table 8. Type III, Style 2 Quadruple V-Block
Permitted Deviations (inch)
Parallelism of “V” to Base and Side 0.0003 0.0012
Flatness of Working Faces
End/Side Square to Base
Parallelism of Opposite Faces
Grade
“V” Centrality
Matching Tolerance
Grade A 0.0003 Grade B 0.0005
0.0005 0.001
0.0005 0.001
0.0003 0.0012
0.0002 0.001
Grade Characteristics Grade A • Steel alloy • Surface finish NTE 32 µ in • Material hardness 50–62 RC Grade B • Mild steel or high grade cast steel • Surface finish NTE 63 µ in • Material hardness 40–45 RC steel / 200–280 BHN cast steel
Nominal Dimensions
All Grades, Designating Size
Length (mm)
Height (mm)
Width (mm)
Maximum Capacity (mm) 20 × 1 – 30 × 1 – 40 × 1 – 50 × 1 20 × 1 – 30 × 1 – 40 × 1 – 50 × 1 30 × 1 – 40 × 1 – 50 × 1 – 60 × 1 30 × 1 – 40 × 1 – 50 × 1 – 60 × 1 40 × 1 – 50 × 1 – 60 × 1 – 70 × 1 60 × 1 – 70 × 1 – 80 × 1 – 100 × 1
1 2 3 4 5 6
95 100 120 120 150 200
70 100 120 120 150 200
35 30 35 60
75 100
Dimensions of deviations are in inches; Nominal dimensions are in mm.
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