Machinery's Handbook, 31st Edition
1880 Dowel Pins British Standard Parallel Steel Dowel Pins.—Metric Series BS 1804: Part 2: 1968
L
D
20°– 40°
a
Nominal Diameter D , mm
1 1.5 2 2.5
3
4
5
6 8 1012162025
Nom. Length L , mm
Chamfer a Max., mm 0.3 0.3 0.3 0.4 0.45 0.6 0.75 0.9 1.2 1.5 1.8 2.5 3 4 Standard Sizes 4 d d 6 d d d d 8 d d d d d 10 d d d d d 12 d d d d d d 16 d d d d d d d 20 d d d d d d d 25 d d d d d d d 30 d d d d d d d 35 d d d d d d 40 d d d d d d d 45 d d d d d d 50 d d d d d d 60 d d d d d d 70 d d d d d 80 d d d d d 90 d d d d 100 d d d 110 d d d 120 d d Limits of Tolerance on Diameter Grade a 1 2 3 Tolerance Zone m5 h7 h11 Nom. Dia., mm Over To & Incl. Limits of Tolerance, 0.001 mm 3 +7 +2 0 − 12 b 0 − 60 3 6 +9 +4 0 − 12 0 − 75 6 10 +12 +6 0 − 15 0 − 90 10 14 +15 +7 0 − 18 0 − 110 14 18 +15 +7 0 − 18 0 − 110 18 24 +17 +8 0 − 21 0 − 130 24 30 +17 +8 0 − 21 0 − 130 a The limits of tolerance for grades 1 and 2 dowel pins have been chosen to provide satisfactory assembly when used in standard reamed holes (H7 and H8 tolerance zones). If the assembly is not satisfactory, refer to BS 1916: Part 1, Limits and Fits for Engineering, and select a different class of fit. b This tolerance is larger than that given in BS 1916, and has been included because the use of a closer tolerance would involve precision grinding by the manufacturer, which is uneconomic for a grade 2 dowel pin. The tolerance limits on the overall length of all grades of dowel pin up to and including 50 mm long are +0.5, − 0.0 mm, and for pins over 50 mm long are +0.8, − 0.0 mm. The Standard specifies that the roughness of the cylindrical surface of grades 1 and 2 dowel pins, when assessed in accordance with BS 1134, shall not be greater than 0.4 μ m CLA (16 CLA).
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