1、BRITISH STANDARD BS328-1:1993 Incorporating Amendment No.1 Drills and reamers Part 1: Specification for twist drills UDC 621.951.4BS328-1:1993 This British Standard, having been prepared under the directionof the Machine, Engineers and Hand Tools Standards Policy Committee, waspublished under the au
2、thorityof the Standards Boardand comes into effect on 15April1993 BSI09-1999 First published June1928 Second edition August1950 Third edition December1959 Fourth edition March1986 Fifth edition April1993 The following BSI references relate to the work on this standard: Committee referenceMTE/5 Draft
3、 for comment91/80383 DC ISBN 0 580 21526 1 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Machine, Engineers and Hand Tools Standards Policy Committee (MTE/-) to Technical CommitteeMTE/5, upon which the following bodies were represented
4、: Federation of British Engineers Tool Manufacturers Society of British Aerospace Companies Limited Amendments issued since publication Amd. No. Date Comments 8044 April1994 Indicated by a sideline in the marginBS328-1:1993 BSI 09-1999 i Contents Page Committees responsible Inside front cover Forewo
5、rd ii 1 Scope 1 2 References 1 3 Definitions 1 4 Dimensions 4 5 Features of design 4 6 Materials and hardness 5 7 Marking 8 8 Performance 8 Annex A (normative) Method of test 32 Figure 1 Twist drill terms. General features 2 Figure 2 Twist drill terms. Point geometry 2 Figure 3 Normal lead and helix
6、 3 Figure 4 Shorter lead and quicker helix 4 Figure 5 Longer lead and slower helix 4 Figure 6 Minimum web thickness 6 Figure 7 Tolerance on web centrality 6 Figure 8 Maximum permissible variation in flute divide 7 Figure 9 Land width 8 Figure 10 Difference in height of major cutting edges 9 Figure 1
7、1 Radial runout tolerance 10 Figure 12 Parallel shank jobber series twist drills 11 Figure 13 Parallel shank stub series twist drills 13 Figure 14 Parallel shank long series twist drills 15 Figure 15 Parallel shank extra long series twist drills 17 Figure 16 Morse taper shank twist drills 19 Figure
8、17 Morse taper shank extra long twist drills 23 Figure A.1 Penetration rates (metric) 33 Figure A.2 Penetration rates (imperial) 34 Table 1 Parallel shank jobber series twist drills. Preferred sizes 11 Table 2 Parallel shank stub series twist drills. Preferred sizes 13 Table 3 Parallel shank long se
9、ries twist drills. Preferred sizes 15 Table 4 Parallel shank extra long series twist drills. Preferred sizes 17 Table 5 Morse taper shank twist drills. Preferred sizes 19 Table 6 Morse taper shank extra long twist drills. Preferred sizes 23 Table 7 Parallel shank jobber series twist drills. General
10、sizes 25 Table 8 Parallel shank stub series twist drills. General sizes 26 Table 9 Parallel shank long series twist drills. General sizes 27 Table 10 Morse taper shank twist drills. General sizes 28 Table 11 Limits of tolerance on diameter 31 Table 12 Flute length l of Morse taper shank extra long t
11、wist drills 31 Table 13 Limits of tolerance on overall length and flute length 31 Table 14 Material cutting portion only 31 Table A.1 Table of penetrations (metric) 32 Table A.2 Table of penetrations (imperial) 32 List of references Inside back coverBS328-1:1993 ii BSI 09-1999 Foreword This Part of
12、BS328 has been prepared under the direction of the Machine, Engineers and Hand Tools Standards Policy Committee. It was first published in1928; revised editions were published in1950,1959 and1986. The1959 revision was divided into Parts, twist drills being included in Part1. In the development of th
13、e subject matter covered by Part1, the1950 edition was the first to indicate preferred drill sizes as a means of rationalizing both the production and the use of drills. The1959 edition began to reflect the international standardization of drills, the process continued in the1986 edition. The main p
14、urpose of the present edition is to reflect the international agreement on drill design. With the exception of the imperial size extra long drills the contents of this Part of BS328 relating to drill diameters, lengths, and tolerances are in accordance with ISO235, ISO494, ISO3291 and ISO3292, publi
15、shed by the International Organization for Standardization (ISO). The flute lengths, overall lengths and design parameters specified in this standard have been arrived at after very full discussion at international level. Special attention is drawn to the fact that, in addition to tabulating the pre
16、ferred sizes in which metric drills and imperial drills will normally be available, comprehensive general tables are given for each type of drill; these ensure that drills with non-listed diameters, when specially required, will be made to preferred shank, flute and overall length dimensions. This P
17、art of BS328 supersedes BS328-1:1986 which is withdrawn. Other Parts of BS328 are: Part2: Combined drills and countersinks (centre drills); Part3: Specification for the dimensions of core drills; Part4: Specification for dimensions of reamers; Part5: Specification for the dimensions of countersinks
18、and counterbores; Part6: Countersinks, 90 , with parallel shanks and solid pilots (Identicalwith ISO4205); Part7: Counterbores with parallel shanks and solid pilots (Identical with ISO4206); Part8: Spot drills (Identical with ISO10898). A British Standard does not purport to include all the necessar
19、y provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1to34,
20、 an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS328-1:1993 BSI 09-1999 1 1 Scope This Part of BS328 specifies requirements for the dimension
21、s, design, materials, hardness values and performance for twist drills made of high-speed steel with either parallel or Morse taper shanks. A method of test for the drills specified is given in Annex A. NOTEThe requirements in this standard may also form the basis for the specification of special pu
22、rpose twist drills as agreed between the buyer and supplier. This British Standard is not applicable to woodworking or do-it-yourself (D.I.Y) drills. Its use is for drills manufactured for general engineering applications. 2 References 2.1 Normative references This Part of BS328 incorporates, by ref
23、erence, provisions from specific editions of other publications. These normative references are cited at the appropriate points in the text and the publications are listed on the inside back cover. Subsequent amendments to, or revisions of, any of these publications apply to this Part of BS328 only
24、when incorporated in it by updating or revision. 2.2 Informative references This Part of BS328 refers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, but reference should be
25、made to the latest editions. 3 Definitions For the purposes of this Part of BS328 the following definitions apply. 3.1 Types of twist drill 3.1.1 parallel shank jobber series twist drill a drill having two helical flutes and a parallel shank of approximately the same diameter as the cutting end 3.1.
26、2 parallel shank stub series twist drill a shortened form of parallel shank jobber series twist drill, the reduction in length being in the flute length 3.1.3 parallel shank long series twist drill a lengthened form of the parallel shank jobber series twist drill, the increase in length being in the
27、 flute length 3.1.4 parallel shank extra long series twist drill a lengthened form of the parallel shank jobber series twist drill, longer than the long series, the increase in length being in the flute length 3.1.5 morse taper shank twist drill a drill having two helical flutes and a standard Morse
28、 taper shank 3.1.6 morse taper shank extra long twist drill a lengthened form of the Morse taper shank twist drill, the increase in length being in the flute length 3.2 Other terms 3.2.1 axis the longitudinal centreline NOTESee Figure 1. 3.2.2 back taper (longitudinal clearance) the reduction in dia
29、meter per unit length of drill from the point towards the shank 3.2.3 body the portion of a drill extending from the extreme cutting end to the commencement of the shank NOTESee Figure 1. 3.2.4 body clearance the portion of the body surface reduced in diameter to provide diametral clearance NOTESee
30、Figure 1. 3.2.5 body clearance diameter the diameter over that surface of the drill body situated behind the lands NOTESee Figure 2. 3.2.6 chisel edge the edge formed by the intersection of the flanks NOTESee Figure 2. 3.2.7 chisel edge angle the obtuse angle included by the chisel edge and a line f
31、rom either outer corner to the corresponding end of the chisel edge, the angle being measured in a plane perpendicular to the drill axis NOTESee Figure 2.BS328-1:1993 2 BSI 09-1999 3.2.8 chisel edge corner a corner formed by the intersection of a lip and the chisel edge NOTESee Figure 2. 3.2.9 depth
32、 of body clearance the amount of diametral reduction per side to provide body clearance NOTESee Figure 2. Figure 1 Twist drill terms. General features Figure 2 Twist drill terms. Point geometryBS328-1:1993 BSI 09-1999 3 3.2.10 diameter, d the measurement across the cylindrical lands at the outer cor
33、ners of a drill NOTESee Figure 2. 3.2.11 face the portion of the flute surface, adjacent to the lip, on which the chip impinges as it is cut from the work NOTESee Figure 2. 3.2.12 flank one of the surfaces on a drill point that extends behind a lip to the following flute NOTESee Figure 2. 3.2.13 flu
34、tes the grooves in the body of a drill that provide lips, permit the removal of chips and allow cutting fluid to reach the lips NOTESee Figure 1. 3.2.14 flute length, l the axial length from the extreme end of the point to the termination of the flutes at the shank end of the body NOTESee Figure 1.
35、3.2.15 heel the edge formed by the intersection of the flute surface and the body clearance NOTESee Figure 2. 3.2.16 helix angle the angle between the leading edge of a land and the drill axis NOTESee Figure 3. 3.2.17 lands the cylindrically ground surfaces on the leading edges of the drill flutes N
36、OTESee Figure 1. 3.2.18 land width the width of the land measured at right angles to the flute helix NOTESee Figure 2. 3.2.19 lead of helix the distance measured parallel to the drill axis between corresponding points on the leading edge of a flute in one complete turn of the flute NOTESee Figure 1.
37、 3.2.20 left-hand cutting drill a drill that rotates in a clockwise direction when viewed on the point end of the drill 3.2.21 lip (cutting edge) the edge formed by the intersection of a flank and a face NOTESee Figure 2. 3.2.22 lip clearance angle the angle formed by a flank and a plane at right an
38、gles to the drill axis, normally measured at the periphery of the drill NOTESee Figure 2. 3.2.23 lip length the minimum distance between the outer corner and the chisel edge corner of a lip NOTESee Figure 2. 3.2.24 outer corner a corner formed by the intersection of a lip and the leading edge of a l
39、and NOTESee Figure 2. 3.2.25 overall length, L the length over the extreme ends of the point and the shank NOTESee Figure 1. 3.2.26 point the sharpened end of a drill, consisting of all that part of the drill that is shaped to produce lips, faces, flanks and a chisel edge NOTESee Figure 2. 3.2.27 po
40、int angle the included angle of the cone formed by the lips NOTESee Figure 2. Figure 3 Normal lead and helixBS328-1:1993 4 BSI 09-1999 3.2.28 quick helix angle a helix angle that is larger in angular value (i.e.in number of degrees) than the normal helix angle, thereby shortening the lead of helix N
41、OTESee Figure 4. 3.2.29 rake angle the angle between a face and a line parallel to the drill axis NOTE 1At the periphery of the drill the rake angle is equivalent to the helix angle NOTE 2See Figure 2. 3.2.30 relative lip height the distance between two planes, perpendicular to the drill axis, each
42、of which passes through an outer corner of the drill NOTESee Figure 2. 3.2.31 right-hand cutting drill a drill that rotates in a counter-clockwise direction when viewed on the point end of the drill 3.2.32 shank the portion of a drill by which it is held and driven NOTESee Figure 1. 3.2.33 slow heli
43、x angle a helix angle that is smaller in angular value (i.e.in number of degrees) than the normal helix angle, thereby lengthening the lead of helix NOTESee Figure 5. 3.2.34 web the central portion of a drill situated between the roots of the flutes and extending from the point towards the shank NOT
44、E 1The point end of the web forms the chisel edge. NOTE 2See Figure 2. 3.2.35 web taper the increase in the web thickness from the point of the drill to the shank end of the flutes 3.2.36 web thickness the minimum dimensions of the web measured at the point end of the drill NOTESee Figure 2. 4 Dimen
45、sions 4.1 Preferred sizes of drills shall conform to the dimensions, and Morse taper shanks where applicable, given in Table 1, Table 2, Table 3, Table 4, Table 5 or Table 6. 4.2 Non-preferred sizes shall conform to the dimensions, and Morse taper shanks where applicable, given in Table 7, Table 8,
46、Table 9 or Table 10. 4.3 Shanks shall be either parallel without driving tenon or of Morse taper shank with tang. 5 Features of design NOTEThe helix angle is left to the manufacturers discretion. 5.1 General Twist drills shall be supplied sharpened and ready for use. The flutes shall be designed so
47、that the cutting lips are equal. Both right-hand and left-hand cutting drills may conform to this standard, but unless otherwise ordered, a right-hand cutting drill shall be supplied. 5.2 Cutting diameter The tolerance on the cutting diameter, d, of a drill, as measured across the lands at the outer
48、 corners, shall be as shown in Table 11 (i.e.h8 as specified in BS4500-1.1:1990 and BS4500-1.2:1990). 5.3 Back taper The drill diameter shall decrease by between0.0002mm and0.0008mm per millimetre linear distance from the outer corner towards the shank. The total back taper shall not exceed0.25mm. N
49、OTEBelow6.0mm diameter, back taper is not a requirement but may be provided. NOTEThe lead is shorter than normal. Figure 4 Shorter lead and quicker helix NOTEThe lead is longer than normal. Figure 5 Longer lead and slower helixBS328-1:1993 BSI 09-1999 5 5.4 Parallel shank The tolerance on the shank shall be h11 (as specified in BS4500-1.1:1990 and BS4500-1.2:1990) for shank diameters less than6.0mm. For shank diameters6.0mm and above, the tolerance shall bef11 (as specified in B
