1、Designation: E 210 63 (Reapproved 2005)Standard Specification forMicroscope Objective Thread1This standard is issued under the fixed designation E 210; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A nu
2、mber in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This Standard is American National Standard Microscope Objective Thread (ANSI B1.111958) as developed by American NationalStandards Committee B1 on
3、Standardization and Unification of Screw Threads under the sponsorship of The American Society ofMechanical Engineers and the Society of Automotive Engineers. It is copyrighted by and is reprinted with the permission of thepublishers. The American Society of Mechanical Engineers, 345 East 47th St.,
4、New York, NY 10017.GENERAL AND HISTORICAL1. Scope1.1 This standard covers the screw thread used for mountingthe objective assembly to the body or lens turret of micro-scopes. It is based on, and intended to be interchangeable with,the screw thread introduced and adopted many years ago by theRoyal Mi
5、croscopical Society of Great Britain, generally knownas the “RMS thread” and now almost universally accepted asthe basic standard for microscope objective mountings. Formalrecognition, however, has been extremely limited.2. Referenced Documents2.1 ASTM Standards:ASA B1.61944 Truncated Whitworth Thre
6、ads22.2 ANSI Standard:B 1.71949 Nomenclature, Definitions, and Letter Symbolsfor Screw Threads33. Terminology3.1 The nomenclature, definitions, and letter symbols usedin this standard are in conformance with ANSI B1.71949.4. Truncated Whitworth Thread4.1 Because of its British origin, the basic thre
7、ad possessesthe British Standard Whitworth form, having an included angleof 55 and rounded crests and roots. This same full Whitworthform is also employed as the design, or maximum material,form by the British. The presence (American National) stan-dard, however, the design thread form established i
8、n AmericanWar Standard ASA B1.61944, has been adopted.5. Pitch Diameter Allowance and Tolerances5.1 The pitch diameter allowance and tolerances promul-gated in June 1924 for the RMS thread were subsequentlyapplied by most American manufacturers to their truncatedversions and found to be acceptable.
9、Uniformity of practicewith regard to the allowances and tolerances for the otherdiameters never materialized.6. Attributes of Good Fit6.1 Experience has established that the principal attributesof a good fit for microscope objective threads are:6.1.1 Adequate clearance to afford protection against b
10、ind-ing due to the presence of foreign particles or minor threadcrest damage.6.1.2 Sufficient depth of thread engagement to assure secu-rity in the short lengths of engagement commonly encountered.6.1.3 Allowances for limited eccentricities so that central-ization and squareness of the objective are
11、 not influenced bysuch errors in manufacture.7. Need for Good Fit7.1 The need for the above characteristics stems principallyfrom the inherent longevity of optical equipment and therepeated use to which objective threads are subjected. Themeasures necessary to provide these properties precludedadopt
12、ion of the allowances and tolerances recommended forthreads of this pitch in the American War StandardASA B1.61944. The more significant departures from thestandard are:7.1.1 A larger allowance on the pitch diameter of theexternal thread.7.1.2 Smaller tolerances on the major diameter of theexternal
13、thread and the minor diameter of the internal thread.7.1.3 The provision of allowances on the major and minordiameters of the external thread.1This standard is under the jurisdiction of ASTM Committee E41 on LaboratoryApparatus and is the direct responsibility of Subcommittee E41.01 on Apparatus.Cur
14、rent edition approved May 1, 2005. Published October 2005. Originallyapproved in 1963. Last previous edition approved in 1999 as E 21063(1999)e1.2Discontinued 1951, Available from National Bureau of Standards and Tech-nology, Gaithersburg, MD 20899.3Available from American National Standards Institu
15、te, 1430 Broadway, NY,NY 10018.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.2 The values established and further details regardingthem are given under Specifications.8. Other Applications8.1 Though utilized principally for micro
16、scope objectivemountings, this screw thread is recommended also for otheroptical assemblies of microscopes and associated apparatus,such as photomicrographic equipment.SPECIFICATIONS9. Basic Form of Thread9.1 The basic form of the thread for this standard is theBritish Standard Whitworth form. Basic
17、 dimensions are givenin Table 1.10. Design Form of ThreadThe design, or maximum material, forms of both the externaland internal threads conform to the ASA B1.61944. Thedesign dimensions are given in Table 1.11. Lead of ThreadThe thread is of the single (single-start) type.12. Classification12.1 The
18、re is established herein only one class of threadwhich experience has proved to be adequate to meet thedemands of the applications.13. Nominal Sizes13.1 There is only one nominal size having a basic majordiameter of 0.800 in. and a pitch of 0.027778 in. (36 threadsper in.).14. Allowances14.1 Positiv
19、e allowances (minimum clearances) are pro-vided on the pitch, major, and minor diameters of the externalthread. The allowance on the pitch diameter is 0.0018 in., thevalue established by the British Royal Microscopical Society in1924 and now widely regarded as a basic requirement. Thesame allowance
20、is also applied on both the major and minordiameters.14.2 Where interchangeability with product having full-form Whitworth threads is not required, the allowances on themajor and minor diameters of the external thread are notnecessary, since the forms at the root and crest of the truncatedinternal t
21、hread provide the desired clearances. In such cases,either both limits or only the maximum limit of the major andminor diameters may be increased by the amount of theallowance. Benefits are derived principally from changes in themajor diameter where increasing both limits improves thedepth of thread
22、 engagement, and increasing only the maximumlimit grants a larger manufacturing tolerance. However, unlesssuch deviations are specifically covered in purchase negotia-tions, it is to be assumed that the threads will be supplied inaccordance with the tables in this standard.15. Tolerances15.1 In acco
23、rdance with standard practice, tolerances on theinternal thread are applied in a plus direction from the basic(also design) size and tolerances on the external thread areapplied in a minus direction from its design (maximummaterial) size.15.2 The pitch diameter tolerances for the external andinterna
24、l thread are the same and include both lead and angleTABLE 1 Definitions, Formulas, Basic and Design DimensionsProperty Symbol Formula DimensionBasic Thread FormHalf angle of threadAa . 27 30 minIncluded angle of threadA2a . 55 00 minNumber of threads per inchAn . 36Pitch p 1/n 0.027778Height of fun
25、damental triangle H 0.960491p 0.026680Height of basic thread hb0.640327p 0.0178Radius at crest and root of British StandardWhitworth basic thread (not used)r 0.137329p 0.0038Design Thread FormHeight of truncated Whitworth thread khb U = 0.566410p 0.0157Width of flat at crest Fc0.243624p 0.0068Width
26、of flat at root Fr0.166667p 0.0046Basic truncation of crest from basicWhitworth formU 0.073917p 0.00205Basic and Design SizesMajor diameter, nominal and basic D . 0.800Major diameter of internal thread DnD 0.800Major diameter of external threadBDsD2UG 0.7941Pitch (effective) diameter, basic E Dhb0.7
27、822Pitch (effective) diameter of internal thread EnDhb0.7822Pitch (effective) diameter of external threadCEsDhbG 0.7804Minor diameter, basic KD2hb0.7644Minor diameter of internal thread KnD2k0.7685Minor diameter of external threadBKsD2hbG 0.7626Allowance at pitch (effective) diameterB,CG . 0.0018AAl
28、l other dimensions are given in inches.BAn allowance equal to that on the pitch diameter is also provided on the major and minor diameters of the external thread for additional clearance and centralizing.CAllowance (minimum clearance) on pitch (effective) diameter is the same as on British RMS threa
29、d.E 210 63 (2005)2errors. They are derived from the RMS “standard” of 1924 andare the same as for the current British RMS thread.15.3 The tolerance on the major diameter of the externalthread and the tolerance on the minor diameter of the internalthread are the minimum values which experience has de
30、mon-strated to be practicable. Adequate depth of thread engagementis thereby assured.15.4 All tolerances are given in Table 2.16. Lengths of Engagement16.1 The tolerances specified herein are applicable tolengths of engagement ranging from18 to38 in. (approximately15 to 50 % of the basic diameter).
31、Lengths of engagementexceeding these limits are seldom employed and, consequently,are not provided for in this standard.16.2 For microscope objective assemblies the length ofengagement most generally employed is18 in.17. Limits of Size17.1 The limits of size for both the external and internalthread
32、are given in Table 2. Their application is illustrated inFig. 1.18. Thread Designation18.1 This screw thread shall be designated on engineeringdrawings, in specifications, and on tools and gages by thesymbol “AMO” preceded by the basic major diameter in inchesand the number of threads per inch, as g
33、iven below:(1) 0.80036 AMO19. Keywords19.1 microscope; threadTABLE 2 Limits of Size and TolerancesA0.80036 AMOElementMajor Diameter Pitch Diameter Minor Diametermax min tolerance max min tolerance max min toleranceExternal threadInternal thread0.79410.8092B0.79110.80000.0030 0.78040.78520.77740.7822
34、0.00300.00300.76260.77150.7552C0.7685 0.0030AAll dimensions are given in inches.BExtreme maximum major diameter produced by a new threading tool having a minimum flat of p/20 ( = 0.0014 in.). This maximum diameter is not controlled by gagesbut by the form of the threading tool.CExtreme minimum minor
35、 diameter produced by a new threading tool having a minimum flat of p/12 ( = 0.0023 in.). This minimum diameter is not controlled by gagesbut by the form of the threading tool.E 210 63 (2005)3APPENDIX(Nonmandatory Information)X1. Recommended Gage Dimensions of Microscope Objective Thread 0.80036 AMO
36、TABLE X1.1 Recommended Gage Dimensions of Microscope Objective Thread 0.80036 AMONOTE 1Ring and plug gages made in accordance with the above dimensions are not suitable for checking British product, the rounded roots of whichwill not pass the flat crest truncations of the gages. However, British gag
37、es, which are made to check the full Whitworth form of thread, will acceptAmerican product.Dimension Symbol Formula DimensionA“Go Setting” Thread Plug Gage (AGo)Dgmax Major diameter, max DsMax 0.7941Dgmin Major diameter, min DgMax 0.0004 0.7937Egmax Pitch (effective) diameter, max EsMax 0.7804Egmin
38、Pitch (effective) diameter, min EgMax 0.0002 0.7802“Not Go Setting” Thread Plug Gage (ANot Go)Dgmin Major diameter, min DsMax 0.7941FIG. 1 Disposition of Tolerances, Allowances, and Crest Clearances for AMO ThreadE 210 63 (2005)4TABLE X1.1 ContinuedDimension Symbol Formula DimensionADgmax Major diam
39、eter, max DgMin + 0.0004 0.7945Egmin Pitch (effective) diameter, min EsMin 0.7774Egmax Pitch (effective) diameter, max EgMin + 0.0002 0.7776“Go” Thread Ring Gage (GGo)Egmax Pitch (effective) diameter, max EgMax“ Go” A Plug 0.7804Egmin Pitch (effective) diameter, min EgMin “Go” A Plug 0.7802Kgmax Min
40、or diameter, max DnMin2hb0.7644Kgmin Minor diameter, min KgMax 0.0004 0.7640“Not Go” Thread Ring Gage (GNot Go)Egmin Pitch (effective) diameter, min EgMin “Not Go” APlug0.7774Egmax Pitch (effective) diameter, max EgMax “Not Go” APlug0.7776Kgmin Minor diameter, min EsMin p/3 0.7681Kgmax Minor diamete
41、r, max KgMin + 0.0004 0.7685“Go” Thread Plug Gage (CGo)Dgmin Major diameter, min DnMin 0.8000Dgmax Major diameter, max DgMin + 0.0004 0.8004Egmin Pitch (effective) diameter, min EnMin 0.7822Egmax Pitch (effective) diameter, max EgMin + 0.0002 0.7824“Not Go” Thread Plug Gage (CNot Go)Dgmax Major diam
42、eter, max EnMax + p/3 0.7945Dgmin Major diameter, min DgMax 0.0004 0.7941Egmax Pitch (effective) diameter, max EnMax 0.7852Egmin Pitch (effective) diameter, min EgMax 0.0002 0.7850Tolerance in leadTolerance on half-angle of thread60.0002 in.60 20 minAAll dimensions are given in inches.ASTM Internati
43、onal takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely thei
44、r own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should b
45、e addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standard
46、s, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).E 210 63 (2005)5
