Drawing Office Practice for ScrewThreads
1.Scope
on dravinga of screv chreads and threaded fastners and the expresaion on This Japanese Industrial Standard provides the methods of representationdrawing of screw threads.
with JIS B 0001.
Figure as a rule.The root of inplete thread portlons shall be shoum by oblique straight line and the length of inplete-thread portion shall beput if necessary.
and inplete thread portions shall be fine full lines (broken lines of In the sinplified dravings ot screw threads the lines shoving the rootsshowing the divisions betveen the plete-and inplete-thread portions Intermediate thickness for invisible parts)aa showm in Figure and the lineshall be thick full lines (broken lines of intermediate thickness forinvisible parts).
Figure
screws set screws wood screvs and screv-threaded holes shall be shovn by 2.2 Engaging parts of screw threeds bolts nuts stud bolts machinerule.However 1n the especially simplified drawings as 3.1 (b) 3.2 （b) the use of the simplified drawings as showm in Attached Fig. 1 to 7 as aFig.7 (b) inplete thread portion shall be neglected irrespective of and 3.3 (b) of Attached Fig.3 Attached Fig.4 Attached Fig.5 and Attachedthe provislons of 2.1.
3.Expresslon of Serew Threads
3.1 The expression of a screw thread shall be posed as given belov of the designation and grade of screw thread and the hand and number of thread and shall be put above the horizontal line attached to the leaderline indicating the line showing the crest of external thread or root ofInternal thread by the methods specified under 3. of JIS B 0123. However the hand of thread shall be omitted for right-hand thread and the number ofthread for single thread.Also the grade of screu thread may be omitted vhen it is unnecessary.
The expression of metric trapezoidal screw thread shall be as given in 4.
3.2 When the surface roughness of screw thread is to be expressed itshal1 be put at the endof the expression for the screw thread with the indication mark for the surface or the mark for surface finish specified inJIS B 0031 (see 8.1 and 8.2of Attached Fig.8).
3.3 When the lead of multiple thread is to be expressed it shall be putHowever this rule does not apply to metric trapezoidal screw thread. after the designation of screv thread inserted between round brackets.
Example:Double TH 32 (1ead: 12) (see 8.3 of Attached F1g. 8)
8 screw thread the word"screw thread" shall be added behind the grade of 3.4 When it is necessary to clarify that the expression is concerned withscrev thread （see Attached Fig.9).
3.5 The thread length of internal screw thread and the hole size anddepth before threading 1f they are to be expressed shall be as exampled 1n Attached Fig.10.
3.6 The grades of externel and internal screw threads simultaneously at aengaging part of screw threads 1f required to be expressed shell be as exampled in Attached Fig.1l.
3.7 When it 1s necessary to express the posit1on of bas1c diameter oftoper pipe thread the designation of the basic diameter shell be put in1te position (see Attached Fig.12).
taper plpe thread the particulars of the Internal and external threade shal1 3.8 For the bination of internol parallel pipe thrcad snd extcrnalbe put above the horizontal line attached to the end of the leader line 1nthat order.(see Attached Fig.13).
4. Expresslon of Metrlc Trapezoldal Threads
For expresatng a metrlc trapezoidal thread the symbol representlng thetype of screw thread nomlnal dlameter of screw thread lead pitch hand ofattached to the end f the leader line Indicating the crest of the external thread，and grade of screw thread shall be put ahove the horizontal linethread or root of Internal thread by the method specified in 4of JIS B 0123.(see Attached Fig.14).
Attached Fig.1Engaging Part of Screw Threads
Attached Fig.2 Engaging Part of Screv Threads(for Stud Bolt)
Section AA
Attached Fig.] Bolt and Nut
3.1 HexagonHeadBolt uogexag pue
3.2 Square Head Bolt and Square Nut
3.3 Hexagon Socket Head Cap Bolt
（q）
B 0002- Attached Fig.4 Attached Fig.5 Attached Fig.6 Slotted Head Hachine Cross Recessed Head Set Screw and Screw Machine Screv Wood Screv 4.14.24.35.15.25.36.16.26.3 Pan Head* Oval Flat Pan*0valFlat Slotted Slotted Cylinder Counter- Head Head Counter- Head Set gon Head Head sunk sunk Screw Socket Hood
Head Head Set Screw
Screw
Note":To stress that the head is of pan-head type slightly
Attached Fig.7 Screv-threaded Hole (a)（q）
18
-B 0002-
Attached Flg.8
Attached. Fig.11
