I MEC I. Section 8: Dimensioning Identification. Completion guidance. h " it J PURPOSE

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1 Sectin 8: Dimensining dentifictin PURPOSE This sectin ims t enble the student t extend their knwledge f Drwing nterprettin frm Engineering Drwings prduced t AS1100 stndrd. Objectives At the end f this sectin yu shuld be ble t: D nterpret infrmtin n detil drwings f engineering cmpnents. D nterpret infrmtin n detil drwings f engineering ssemblies. Cmpletin guidnce The wrk my need t be cmpleted inside nd utside the clssrm if the mjrity f exercises re ttempted. MEC076 Engineering Drwing nterprettin 1 h " it J MEC

2 Dimensining identifictin T cver this sectin the student needs t study the fllwing sheets nd be ble t recgnise nd understnd wht the fllwing dimensins re depicting. Liner dimensins Angulr dimensins Rdii Dimeter Nt t scle dimensin - Auxiliry dimensins Reference dimensin Cmmn feture Tbulr presenttin Squres Hexgns Hles Screw threds Tpers hrizntl, verticl r blique stright dimensins indictin f ngle in degrees, minutes nd secnds r deciml mesure s required. methd used t indicte runded prt. methd used t indicte circle, ften hle. methd f shwing tht dimensin is nt t the scle shwn n the drwing. A thick line is shwn under the dimensin. methd f shwing dimensin tht cn be clculted using existing dimensins shwn n the drwing. A dimensin tht is bsiclly nt necessry but hndy t hve. They re nt tlernced in ny wy nd re enclsed in prenthesis. nther nme fr uxiliry dimensin. methd f dimensining feture tht repets itself. tht is, R5 TYP ( csting hs rdii f 5mm n ll crners typicl) prticulr shpe tht cmes in rnge f sizes. Tht is, ngle irn. (See exmple f vrying size pins t the right). designted by drwing smll squre beside the dimensin which gives the distnce crss the flts. designted by the bbrevitin Hex. Nte: hexgn cn either be dimensined crss the flts (AF) r crss the crners (AC). Tht is, Hex. 5mm AF. lwys be lert. Hex. 86mm AC. Usully AF, but things t be nted here re the shpe f the hle, hw it is t be prduced (drilled, drilled nd remed, punched, brched etc.), whether it is blind, (des nt g ll the wy thrugh the mteril) r thrugh hle (ges ll the wy thrugh the mteril). things t be nted here re the shpe f the thred (vee, squre, cme, buttress, etc.), dimeter, tpping size nd pitch, s well s be wre tht there re mny different thred systems incrprting the ld imperil threds s well s metric nd specil threds. methd f dimensining tpers. Refer t the prticulr symbl Prfile Dtum R D S0 SR used here. methd f dimensining shpe tht des nt hve cnstnt curve r tper. n edge, fce, centre line, centre f hle etc. frm which ll dimensins re tken. Prt millimetres N. A B C D E n tht is mnufctured in 6 different sizes. ndicte5 tht dimen5in refer5 t the dimeter f circle r cylinder, t 5hll be plced in frnt f the dimensin. ndicte5 tht dimen5in refer,; t rdiu5 f prt f circle r cylinder. t 5hll be plced in frnt f the dimen5in. ndicte5 tht dimen5in refer5 t the width cr055 flw f 5qure 5ectin. t 5hll be plced in frnt f the dimen5in. ndicte5 tper nd it5 directin. The centre-line5 5hll be prllel with the xi5 r plne f 5ymmetry f the tpered feture. t 5hll be plced in frnt f the 510pe rti. ndicte5 510pe nd it5 directin. The b5e 5hll be prllel t the dtum plne. t 5hll be plced in frnt f the 510pe rti. ndicte5 the centre-line f prt, feture, Or grup f feture5. t 5hll be lcted djcent t, r n the centre-line.. ndicte5 the dimeter f 5phericl 5urfce. t 5hll be plced in frnt f the dimen5in. ndicte5 the rdiu5 f 5phericl 5urfce. t 5hll be plced in frnt f the dimen5in. MEC076 Engineering Drwing nterprettin 1 ", it: 119 MEC

3 Dimensins This sectin sets ut the recmmended methds used when dimensining drwings, s tht they will cnfrm t the Austrlin Stndrds drwing prctice ASll R5typ Ntes: The drwn utlines indicte the shpe f n bject. The dimensins indicte its size. Only thse dimensins necessry fr mking the bject shuld be shwn n the drwing. All dimensins shuld be shwn n the drwing nce nly. Dimensins shuld be shwn n the view where the detil is seen clerest s n utline. 5 R hles 05---' Adjusting plte R15,--_8 hles 07 equispced 135 Splice plte = t hr AlF R15 24 R15 Hex 12A1F.e /'S '- "$-". 6 hles 08 n FeD The dimensins n these views re ll unidirectinl (red in ne directin) MEC076 Engineering Drwing nterprettin 1, " it: 120 MEC

4 Prjectin nd dimensin lines P;,,,, ",. f must tuch the prjectin line Prjectin line J These g t within lmm f prt being dimensinsd Lctin f dimensins A Hrizntl dimensins re plced bve nd in the centre f the dimensin line. B Verticl dimensins re plced bve nd in the centre f the dimensin line, usully when seen frm the right hnd side f the drwing sheet. C Angulr dimensins. Dimensining smll spces Tw cmmn methds re shwn fr sizes 2 nd 3.,,-Outline f bject Applictin 0] L 1mm gp r_ lmm extensin Dimensin line Dimensin lines spced t suit figures nd clrity Dimensining rdii The leder line shuld be in line with the centre f the rc. The methds shwn my vry n CAD. Dimensining dimeters The methd shwn my vry n CAD. Dimensins relting t dtum line r surfce Auxiliry dimensins These re dimensins used s ) guide nly. Often they re - \- verll sizes. They re shwn in prenthesis. Exmple (60) Dimensins nt t scle 2 4() 4() f--3 f prt f drwing is nt t the crrect scle it shuld be highlighted by underlining. Exmple 0 10, 0 35, 045. R12 Applictin R16 R8 3 - >.03 Dtum hles! {2 l\( -0- Vfj- ' {B '1> - t- - Vi-)- llbq Dtum -<b- -<b- - > F ,- t= _. -- (60) MEC076 Engineering Drwing nterprettin 1 ti " i ' 121 MEC

5 Psitin f dimensins nd prjectin lines Rule (pplies in mst cses) ncrrect Crrect Rule (pplies in mst cses) ncrrect Crrect 1. Dimensins shuld be kept utside the view if pssible, there re times when it is better fr clrity t put the dimensins n the view A Dimensin lines nd prjectin lines shuld nt crss ne nther. Nte: 1. Smllest dimensin shuld be plced nerest the utline prgressing t lrgest dimensin n the utside. 2. Centre lines cn be extended t ct s prjectin lines when dimensining., ; D nt repet dimensins n the drwings. Length f item will be shwn n either frnt view r tp view, nt n bth. {[J] 21 {g 1 1ZJ 24 [J] 24 5B Prjectin lines cn crss g3 ne nther. 12 Pr Much better r-l (A) D nt use centre lines s dimensin lines, they my be used s prjectin lines (B) Dimensin lines shuld nt be prjectin f surfce. $ - A C B -( 1- & '<;1-6. D nt dimensin fetures shwn by hidden utlines. Only dimensin fetures shwn by utlines if pssible. J-t- -c? L_ J - '-- _. Df _ :::. - -<7-4. D Nt use utlines s dimensining lines. 7. When the nte "dimensins re in millimetres" ppers it is nt necessry t shw the millimetre sign with the dimensins. Nte nt shwn E E t Nte shwn 100mm ALL DMENSONS ARE N MLLMETRES t MEC076 Engineering Drwing nterprettin 1 December. 1998, " i:o 122 MEC

6 Dimensining Liner pitches Hles cn be pitched lng stright line. t is clled pitch line nd drwn s centre line. Vrius methds re in use t dimensin the pitch. Exmples: Methd 1 Methd 2 Methd 3 Methds 3, 4 nd 5 vercme ccumultive errrs. -H-+-+-?-+i-l-- 1 S;;Q H-+-+-?-+-1-j- 1 q 1,75.1, ck- -dr -4- -'-- Eh ck-- fq.j 125?nn f-<k-4 --b -.Jr -Ek- -<k-j- Circulr pitches Hles cn be pitched rund circle clled pitch circle which is scribed s circle r prt circle frm centre. The dimeter f the circle is designted s the pitch circle dimeter r PCD. Exmples: 3 hles.08 $( equispced..-- _n, 34PCD / "- /,, 1 \ _ _. lz!, / Methd 1 //' -T-f)9r.038 1, \ {'", \ r \ "" \0" '.( -...J_-- / 4 hles.09 equispced n 38 fcd psitin s shwn This my be clled pitch circle rdius r fcr..-- _-$ ShOles.0//,- / i C--6 R48 i 25T 1 il l Methd 3 Methd 2 Methd 4 Methd 5 -H-+-+-?-+-1-j t t 2 t<) 5 hles.06.5 equispced fcd \..-- _!.05 / / "- /,, " \. tj 'y.09 Methd 4 Methd 5 :MEC076 Engineering Drwing nterprettin 1 ", i ' 123 MEC076-8i]

7 Exercise 8-1 Dimensining The fllwing drwings f cmpnents cntin sme dimensins tht re incrrectly shwn with regrd t AS 1100 Drw circ e rund, r highlight ny dimensin tht is incrrecty shwn, r culd be cnsidered pr chice f psitin t<) r 15 1 N 0 N L \ Hles E 6 lt10 R ' '/ 1V-i5 0,2 hles 810 \ 15 _$2Q ::: , $hle c-/---...l 0 1"- / t<) 1 \ r '<' lo \0 E 4 t.. 6mm 110. i 1.6mm 1 50 Di MEC076 Engineering Drwing nterprettin 1 ", i:o 124 MEC

8 Dtum Dtums re used t: Prevent tlernce grwth during mrking ut nd mnufcturing T keep imprtnt dimensins reltive t certin psitin Exercise 8-2 My be cmpleted freehnd r n drwing brd. Use pencil s yu cn crrect ny errrs. The plte belw is dimensined rndmly. Dimensin the blnk drwing belw it using the left hnd side nd the bttm edge s dtums. Dtums my be edges r centre lines (shwn belw). The symbl fr dtum is filled in tringle (A). This is plced n the dtum line s shwn. A letter inside circle prvides reference fr the dtum. A -- --dr- ---$- R5 ; R / e$ e (() ---- / 7 hles RJ ;, m 3 hlesrj 6 B O@ [t hle,;.06 \i> --<--$ J -<P----i---- Q [ -Ej} - A LR 5 1b 'r J } 1f 2 -r ; - r k c----e MEC076 Engineering Drwing nterprettin 1 December. 1998,,'J 125 MEC

9 Multi-view dimensining Ech dimensin shuld pper n ne view nly All hrizntl dimensins shuld be redble frm the bttm f the sheet All verticl dimensins shuld be redble frm the right side f the sheet All dimensins shuld be utside the views Exercise 8-3 Dimensin the rthgnl views frm the pictril specifictins Lck supprt smetric L--,--r L.' _---J-r'---""".LL...J t------l ld N -'----, r---'--, ' T------L hles 010 r $ -' $ - ncrrect exmple Crrect exmple Mteril: MS 2 thick ====-lj ALL DMENSONS ARE N MLLMERES MEC076 Engineering Drwing nterprettin 1,'1 it:n 126 MEC