1、GM DAEWOO Auto & Technology EDS Engineering, GM DAEWOO Auto & Technology Standards DRAWING PRACTICE FOR SCREW THREAD Do Not Use on New Programs. Being Replaced by Global Design Standards EDS-A-1022 ISSUED DATE: 1996. 04. 10 REVISED DATE: 2008. 05. 31 VERSION: 3 (Superceded) EDS-A-1022DRAWING PRACTIC
2、E FOR SCREW THREAD PAGE: 1/12 ISSUED DATE: 1996. 04. 10 REVISED DATE: 2008. 05. 31 VERSION: 3 GM DAEWOO Auto & Technology Note: This standard may be applied only for current project drawings generated by CATIA. It is Superceded for all future projects and replaced by Global Design Standards. 1. PURP
3、OSE This standard applies to methods of designating and representing in drawings screw threads and related parts used by GM DAEWOO Auto & Technology Company (hereinafter referred to as the “GMDAT“) Items not shown in this standard shall conform to KS B 0001 (Mechanical Drawing). 2. DESIGNATING THREA
4、DS Designation of threads, which includes nominal size of threads, class of threads, turning direction, and number of threads, is constructed as follows and shall conform to clause 3. Designation of metric taper threads shall conform to clause 4. Turning direction No. of threads Nominal size of thre
5、ads - Class of thread3. INDICATING NOMINAL SIZE AND CLASS OF THREADS, WINDING DIRECTION, AND NUMBER OF THREADS 3.1. Nominal size of threads Nominal size of threads is composed of a symbol representing the thread type, number representing thread diameter(1), and pitch or number of threads per inch (2
6、5.4mm) as follows. The Table 1 shows symbols for threads and examples of thread nominal size Note (1) In case of threads whose diameter is based on simple figures in mm, it corresponds to the nominal diameter. 3.1.1. In case of threads whose pitch is represented in mm Symbol representing thread type
7、 Figure representing thread nominal diameter PitchHowever, in case only one pitch is specified for the same diameter, as in metric coarse screw threads and miniature screw threads, the pitch is omitted in principle. 3.1.2. In case of threads whose pitch is represented by number of threads (excluding
8、 unified threads) Symbol representing thread type - Figure representing thread diameter Thread Number of threadsHowever, in case only one thread number is specified for the same diameter, as in pipe threads, the number of threads is omitted in principle. Also, in case confusion is expected, a “hyphe
9、n (-)“ may replace the “Thread“. 3.1.3. In case of unified threads Symbol or number representing thread diameter - Number of threads Symbol representing thread type EDS-A-1022DRAWING PRACTICE FOR SCREW THREAD PAGE: 2/12 ISSUED DATE: 1996. 04. 10 REVISED DATE: 2008. 05. 31 VERSION: 3 GM DAEWOO Auto &
10、 Technology Table 1. Examples of symbols representing thread type and representation of thread nominal size Division Type of thread Symbol of thread Nominal size Reference standard Metric coarse thread M8 KS B 0201 Metric fine thread M M81 KS B 0204 Miniature thread S S 0.5 KS B 0228 Unified coarse
11、thread UNC 3/8-16UNC KS B 0203 Unified fine thread UNF No.8-36 UNF KS B 0206 Metric trapezoidal thread Tr Tr 102 KS B 0229 External taper thread R R 3/4 Internal taper thread Rc Rc 3/4 In ISO stnd. Taper pipe thread Internal parallel thread Rp Rp 3/4 KS B 0222 Parallel pipe thread G G 1/2 KS B 0221
12、Trapezoidal metric thread TM TM 18 KS B 0227 Trapezoidal Whitworth thread TW TW 20 KS B 0226 Taper thread PT PT 7 Taper pipe thread Internal parallel thread(4)PS PS 7 KS B 0222 For normal use Not in ISO stand. Parallel pipe thread PF PF 7 KS B 0221 Thick conduit tube thread CTG CTG 16 Conduit tube t
13、hread CTG CTC 19 KS B 0223 For normal use BC 3/4 Bicycle thread For spokes BC BC 2.6 KS B 0224 Sewing machine thread SM SM 1/4 thread 40 KS B 0225 Electric lamp thread E E 10 KS C 7702 Tire valve thread for automobile TV TV 8 KS R 4007 For special use Tire valve thread for bicycle CTV CTV8 thread 30
14、 KS R 8044 Notes (1) M1.7, M2.3 and M2.6 of metric threads are not specified in the DMS ISO standard (2) When clear indication of fine threads is necessary, a phrase “fine thread“ may be entered after the pitch in parenthesis. Ex: M81(Fine thread) (3) This internal parallel thread Rp applies only to
15、 the taper external thread R. (4) This internal parallel thread PS applies only to the taper external thread PT EDS-A-1022DRAWING PRACTICE FOR SCREW THREAD PAGE: 3/12 ISSUED DATE: 1996. 04. 10 REVISED DATE: 2008. 05. 31 VERSION: 3 GM DAEWOO Auto & Technology 3.2. Thread class The class of threads, w
16、hich is the combination of figures and letters or letters alone representing thread class, is represented as in Table 2. Here, the classification by thread type shall conform to each related standard. Table 2. Thread class Division Type of thread Division into external and internal thread Example Re
17、ference standards Internal Classes of effective & internal diameters are same 6H Classes of effective & external diameters are same 6g External Classes of effective & external diameters are different 5g 6g Metric thread Internal & external combined (1) 6H/6g, 5H/5g 6g KS B 0235 KS B 0211 KS B 0214 I
18、nternal 3G6 External 5h3 Miniature thread Internal & external combined 3G6/5h3 KS B 0228 Internal 7H External 7e Metric trapezoidal thread Internal & external combined (1)7H/7e KS B 0237 KS B 0219 In ISO stand. Parallel pipe thread External A KS B 0221 Internal & External Internal & external thread
19、classes are same Class 2, When no confusion is expected, word “Class“ may be omitted KS B 0211 KS B 0214 Metric thread Internal & external combined (3) Class 3/2, When no confusion is expected, it may be written “3/2“ - Internal 2B Unified thread External 2A KS B 0213 KS B 0216 Internal B Not in ISO
20、 stand. Parallel pipe thread External A KS B 0221 Notes (1) The method of indicating the class by this combination shall conform to KS B 0235. (2) The method of indicating the class by this combination shall conform to KS B 0237. (3) The method of indicating the class by this combination shall confo
21、rm to “Internal thread class/external thread class of KS B 0235. EDS-A-1022DRAWING PRACTICE FOR SCREW THREAD PAGE: 4/12 ISSUED DATE: 1996. 04. 10 REVISED DATE: 2008. 05. 31 VERSION: 3 GM DAEWOO Auto & Technology 3.3. Turning direction of screw threads As for the turning direction of screw threads, “
22、Left“ shall be indicated in case of left-hand threads, and none in case of right-hand threads. “L“ may be used instead of “Left“. 3.4. Number of thread types In case of multiple threads, “double threads“, “triple threads“ and the like is indicated properly. In case of single threads, nothing is indi
23、cated. “N“ may be used instead of “threads“. 3.5. Examples of thread designation Based on the above 3.13.4, examples of thread designation are shown as follows. In case of representing a combination of an internal thread and external thread with different nominal size, enter both nominal sizes (clas
24、ses also if exist) in the following order using “/“ in-between. : Left-hand double threads fine screw thread (M502) internal thread class 6, tolerance position H : Left-hand single thread coarse screw thread (M10) internal thread 6H and external thread 6g combined : Right-hand single thread unified
25、coarse screw thread (No. 4-40UNC) class 2A : External parallel pipe thread (G1/2) Class A : Internal parallel pipe thread (Rp 1/2) and taper pipe external thread (R 1/2) combined Note(1) It becomes “L2N M502-6H“ if represented according to the provisons in 3.3 and 3.4. 4. DESIGNATING METRIC TRAPEZOI
26、DAL THREAD 4.1. Designation of single row thread The single row metric trapezoidal thread is designated by combining a symbol Tr, which represents thread type (See Table 1), and a figure which represents the nominal diameter and pitch (Example 1). The thread class (See Table 2) is represented succes
27、sively preceded by a hyphen (Example 2). When it is not necessary to indicate thread class, it may be omitted. Turning direction No. of threads Nominal size of threads Class of thread Left(1)2threads(1) M50X2 - 6H Left M10 6H/6g No, 4-40 UNC 2A G1/2 A Rp 1/2 / R1/2 EDS-A-1022DRAWING PRACTICE FOR SCR
28、EW THREAD PAGE: 5/12 ISSUED DATE: 1996. 04. 10 REVISED DATE: 2008. 05. 31 VERSION: 3 GM DAEWOO Auto & Technology (Example 1) : In case of nominal diameter 40mm and pitch 7mm Tr 407 (Example 2) : In case of nominal diameter 40mm, pitch 7mm and internal thread class 7H Tr 407-7H 4.2. Designation of mu
29、ltiple row thread The multiple row metric trapezoidal thread is designated by combining a symbol Tr, which represents thread type, and a figure which represents the nominal diameter, lead and pitch (Example 1). The thread class is represented successively preceded by a hyphen (Example 2). Here, the
30、pitch is represented after the lead in ( ), with the figure preceded by “P“. 4.3. Designation of left-hand thread The left-hand metric trapezoidal thread is designated by affixing the symbol LH to the nominal size described in 4.1 and 4.2 as follow. Example : Tr 407LH Tr 407LH-7H Tr 4014(P7)LH Tr 40
31、7(P7)LH-7e 5. REPRESENTING THREAD FOR MANUFACTURING DRAWING The thread shall be represented simplified as in Fig. 1 and 2. (1) External thread EDS-A-1022DRAWING PRACTICE FOR SCREW THREAD PAGE: 6/12 ISSUED DATE: 1996. 04. 10 REVISED DATE: 2008. 05. 31 VERSION: 3 GM DAEWOO Auto & Technology (2) Intern
32、al thread Fig 1. Representing thread Fig 2. Representing internal thread 5.1. Lines representing the outside diameter of the external thread and inside diameter of the internal thread shall be thick solid lines (medium thickness broken lines when invisible). 5.2. Lines representing the root bottom a
33、nd incomplete thread shall be thin solid lines (medium thickness broken lines when invisible). 5.3. Lines representing the boundary between the complete thread and incomplete thread shall be thick solid lines (medium thickness broken lines when invisible). EDS-A-1022DRAWING PRACTICE FOR SCREW THREAD
34、 PAGE: 7/12 ISSUED DATE: 1996. 04. 10 REVISED DATE: 2008. 05. 31 VERSION: 3 GM DAEWOO Auto & Technology 6. THREAD DRAFTING AND SYMBOL ENTERING 6.1. External thread (Fig. 3 and 4) 6.1.1. Draw the thread crest and boundary in a thick solid line. 6.1.2. Draw the root in a thin solid line. Thread height
35、 K=1/81/10d. 6.1.3. Draw the root of incomplete thread in a 30 Inclined thin solid line. 6.1.4. Represent the flat end by a K45 chamfer, and the round end by the radius R. Fig 3. Representing external thread Left-hand double thread Unified fine thread Left-hand single thread metric fine thread (No.
36、4-4 UNF) metric coarse thread (M302) Class 2 Class 2A (M10) Nut class 2 bolt class 1 Fig 4. Entering symbols 6.2. Internal thread (Fig. 5 and 6) 6.2.1. Make the root diameter “d“ and draw up to the thread depth in a thin solid line. 6.2.2. Make the blind hole diameter “d-2k“, the cut end angle 120,
37、and draw the drilled hole and boundary in a thick solid line. 6.2.3. Draw the root of incomplete thread in a 30 inclined thin solid line . 6.2.4. Represent the internal thread entrance by a K45 chamfer. EDS-A-1022DRAWING PRACTICE FOR SCREW THREAD PAGE: 8/12 ISSUED DATE: 1996. 04. 10 REVISED DATE: 20
38、08. 05. 31 VERSION: 3 GM DAEWOO Auto & Technology Fig 5. Representing internal thread Fig 6. Entering symbols 6.3. To make a thread, a base hole shall be drilled and processed with a tap. (Fig. 7, Table 3) Fig 7. Base hole and threaded hole Table 3. Thread hole Material Driven length A Space below t
39、hread B Thread length C Incomplete thread length E Drilled hole depth F Aluminum Cast iron Brass Bronze Steel 2d 1.5d 1.5d 1.5d d 3p 3p 3p 3p 3p 2d+B 1.5d+B 1.5d+B 1.5d+B d+B 24p 24p 24p 24p 24p C+E C+E C+E C+E C+E EDS-A-1022DRAWING PRACTICE FOR SCREW THREAD PAGE: 9/12 ISSUED DATE: 1996. 04. 10 REVI
40、SED DATE: 2008. 05. 31 VERSION: 3 GM DAEWOO Auto & Technology 6.4. Engaging part of thread Draw the hatching of the external thread to the line representing the crest. Here, the cutting line of the internal thread is drawn to the root of the external thread in a thick solid line. (Fig. 8) Fig 8. Eng
41、aging part of thread 6.5. Combination of pipe thread When an internal parallel pipe thread and an external taper pipe thread are combined, the phrase “internal thread“ precedes “PS“ and “external thread“ precedes “PT“ respectively for identification. (Fig. 9) Fig 9. Pipe thread 7. DRAWING BOLTS AND
42、NUTS To draw the bolt, designate the nominal size of thread, under-head length and thread cut length. 7.1. Names (Fig. 10, 12) and types (Fig. 11, 13) of bolt and nut Fig 10. Bolt and nut Fig 11. General types EDS-A-1022DRAWING PRACTICE FOR SCREW THREAD PAGE: 10/12 ISSUED DATE: 1996. 04. 10 REVISED
43、DATE: 2008. 05. 31 VERSION: 3 GM DAEWOO Auto & Technology Fig 12. Bolt description Fig 13. Right-hand and left-hand threads 7.2. Simplified drawing for manufacturing drawing The center of the chamfer line of hexagon head bolt in Fig. 14 (1) is drawn by a radius of 1.5d. The center arc is extended in
44、 both directions and the intersection point with the end is designated “2“, where a horizontal line is drawn and the midpoint between “2“ and “3“ is designated “4“. An arc is drawn with “4“ as the center and “4-1“ as the radius. Chamfering line of the square bolt in (2) is drawn by a radius of 2d. T
45、he bolt and nut are drawn the same way except for the different head height. Fig 14. Drawing bolt and nut 7.3. Simplified drawing The chamfer line is omitted as in Fig. 14 (3) and (4). The end is made flat, and the incomplete thread is not indicated. This method is used when bolts and nuts are drawn
46、 in a small size. In general, bolts and nuts are arranged as in Fig. 14 (1). EDS-A-1022DRAWING PRACTICE FOR SCREW THREAD PAGE: 11/12 ISSUED DATE: 1996. 04. 10 REVISED DATE: 2008. 05. 31 VERSION: 3 GM DAEWOO Auto & Technology 7.4. Dimensioning of bolts and nuts Enter under-head length and thread cut
47、length or the length and nominal size of thread. (Fig. 15) Fig. 15. Dimensioning 7.5. Machine screw thread and screw nail (reference standards KS B 1021, KS B 1055) The end of the machine screw thread is drawn flat and the incomplete thread is omitted. The slot of the slotted machine screw thread is
48、 represented by a 45 right up-ward inclined line and the cross of the cross recess is represented by two 45 inclined lines. The screw nail is drawn similar to the actual shape. (Fig. 16) Fig 16. Screw thread and screw nail 7.6. Pipe thread The taper may or may not be drawn. When drawn, it shall be l
49、arge to draw attention. (Fig. 17) Fig 17. Pipe thread Stud side Nut side EDS-A-1022DRAWING PRACTICE FOR SCREW THREAD PAGE: 12/12 ISSUED DATE: 1996. 04. 10 REVISED DATE: 2008. 05. 31 VERSION: 3 GM DAEWOO Auto & Technology 8. REFERENCE STANDARDS KS B 0201 Metric unified thread KS B 0203 Unified coarse thread KS B 0204 Metric fine thread KS B 0206 Unified fine thread KS B 0211 Limits of size and tolerance of metric unified thread KS B 0213 Limits of size and tolerance of unifie
