Machinery's Handbook, 31st Edition
918 Reamers the bearing length of the cutting portion of the reamer. One way to do this is to reduce the reamer diameter by 0.010 to 0.030 inch (0.25–0.76 mm), depending on size and length, behind a short full-diameter section, 1 ⁄ 8 to 1 ⁄ 2 inch (3.18 to 12.7 mm) long according to length and size, following the chamfer. The second method is to grind a high back taper, 0.008 to 0.015 inch per inch (or mm/mm), behind the short full-diameter section. These modifications reduce the length of the reamer tooth that can cause the bellmouth condition. Poor Finish: The most obvious step toward producing a good finish is to reduce the reamer feed per revolution. Feeds as low as 0.0002 to 0.0005 inch (0.005 to 0.013 mm) per tooth have been used successfully. However, better reamer life results if the maximum feasible feed is used. The minimum practical amount of reaming stock allowance will often improve finish by reducing the volume of chips and the resulting heat generated on the cutting portion of the chamfer. Too little reamer stock, however, can be troublesome in that the reamer teeth may not cut freely but will deflect or push the work material out of the way. When this happens, excessive heat, poor finish, and rapid reamer wear can occur. Because of superior abrasion resistance, carbide reamers are often used when fine fin ishes are required. When properly conditioned, carbide reamers can produce a large num ber of good-quality holes. Careful honing of the carbide reamer edges is very important. Types and Sizes of Reamers American National Standard Fluted Taper Shank Chucking Reamers— Straight and Helical Flutes, Fractional Sizes ANSI/ASME B94.2-1995 (R2015)
B
B
A
No. of Morse Taper Shank a
No. of Morse Taper Shank a
No. of Flutes 4 to 6 4 to 6 4 to 6 6 to 8 6 to 8 6 to 8 6 to 8 6 to 8 6 to 8 6 to 8 6 to 8 6 to 8 6 to 8 8 to 10 8 to 10
No. of Flutes 8 to 10 8 to 10 8 to 10 8 to 10 8 to 10 8 to 12 8 to 12 8 to 12 8 to 12 8 to 12 8 to 12 10 to 12 10 to 12 10 to 12
Length Overall A
Flute Length B
Length Overall A
Flute Length B
Reamer Dia.
Reamer Dia.
6 6 7 7 8 8 8 8 9 9 9 9
1 1 1 1 1 1 1 1 2 2 2 2 2 2 2
2 2 2 3 3 3 3 3 3 4 4 4 4 4
9 1 ⁄ 2
2 1 ⁄ 2 2 5 ⁄ 8 2 5 ⁄ 8 2 5 ⁄ 8 2 5 ⁄ 8 2 3 ⁄ 4 2 3 ⁄ 4 2 7 ⁄ 8 2 7 ⁄ 8
1 1 ⁄ 2 1 1 ⁄ 2 1 3 ⁄ 4 1 3 ⁄ 4
1 ⁄ 4
27 ⁄ 32
10 10 10 10
5 ⁄ 16
7 ⁄ 8
3 ⁄ 8
29 ⁄ 32 15 ⁄ 16 31 ⁄ 32
7 ⁄ 16
2 2 2 2
1 ⁄ 2
1
10 1 ⁄ 2 10 1 ⁄ 2
17 ⁄ 32
1 1 ⁄ 16 1 1 ⁄ 8 1 3 ⁄ 16 1 1 ⁄ 4 1 5 ⁄ 16 1 3 ⁄ 8 1 7 ⁄ 16 1 1 ⁄ 2
9 ⁄ 16
11 11
19 ⁄ 32
2 1 ⁄ 4 2 1 ⁄ 4 2 1 ⁄ 4 2 1 ⁄ 4 2 1 ⁄ 2 2 1 ⁄ 2 2 1 ⁄ 2
5 ⁄ 8
3 3
11 1 ⁄ 2 11 1 ⁄ 2
21 ⁄ 32 11 ⁄ 16 23 ⁄ 32
12 12
3 1 ⁄ 4 3 1 ⁄ 4 3 1 ⁄ 2
9 1 ⁄ 2 9 1 ⁄ 2 9 1 ⁄ 2
3 ⁄ 4
12 1 ⁄ 2
25 ⁄ 32 13 ⁄ 16
… …
… …
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a American National Standard self-holding tapers (see Table 7a on page 1020 ). All dimensions are given in inches. Material is high-speed steel. Helical flute reamers with right-hand helical flutes are standard. Tolerances: On reamer diameter, 1 ⁄ 4 -inch size, +.0001 to +.0004 inch; over 1 ⁄ 4 - to 1-inch size, + .0001 to +.0005 inch; over 1-inch size, +.0002 to +.0006 inch. On length overall A and flute length B , 1 ⁄ 4 - to 1-inch size, incl., ± 1 ⁄ 16 inch; 1 1 ⁄ 16 - to 1 1 ⁄ 2 -inch size, incl., 3 ⁄ 32 inch.
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