ASME B1.5:1997 pdf download ACME SCREW THREADS
Publisher: The American Society of Mechanical Engineers (ASME)，Three Park Avenue,New York,NY10016; Order Department: 22 Law Drive, Box 2300.Fairfield，NJ 07007-2300
1.4 Reference Temperature
The reference temperature is 68°F (20°C) for dimensions listed.
1.5 Units of Measure
All dimensions and values are expressed in inchesunless otherwise noted.
1.6 Terminology
Definitions, terms, and symbols relating to Acmescrew threads are found in ASME Bl7M. Explanationof ISO fundamental deviation symbols used for allow.ance in this Standard are:
El: lower deviation, internal thread allowance (fundamental deviation).
es. upper deviation, external thread allowance (fundamental deviation); es is always negative for an allowancefit or zero for no allowance
1.7 Computer-Generated Size
All computer-generated values for standard sizesherein are identical to previous Acme publications. Fora nonstandard nominal size, D, apply the next largernominal size given in the table. For computer calculationof Acme product and gage size or tolerance, use ASMEB!.30M and formulas herein. Parties should be advisedin contract.
2 SPECIFICATIONS FOR GENERAL PURPOSEACME SCREW THREADS
2.1 Angle of Thread
The included angle between the flanks of the threadmeasured in an axial plane, shall be 29 deg. The linebisecting this 29 deg angle shall be perpendicular tothe axis of the screw thread.
2.2 Pitch and Lead of Thread
The pitch of the thread is the distance, easuredparallel to its axis, between corresponding points onadjacent thread forms. The lead of a thread is the distance traversed in one revolution of a screw thread.On multiple-start threads,the lead equals pitchmultiplied by the number of starts.
2.3 Height of Thread
The basic height of the thread is equal to one-halfof the pitch.
2.4 Thickness of Thread
The basic thickness of the thread profile at the pitchline is one-half of the pitch.
2.5 Allowance (Minimum Clearance) at Majoland Minor Diameters
A minimum diametral clearance is provided at theminor diameter of all threads by establishing the maximum minor diameter of the external thread 0.020 inless than the basic minor diameter for 10 threads/inand coarser, and 0.010 in. less for finer pitches.
A minimum diametral clearance at the major diameteris obtained by establishing the minimum major diameteof the internal thread 0.020 in. greater than the basicmajor diameter for 10 threads/in. and coarser, and 0.010in. greater for finer pitches.
2.6 Chamfers and Fillets
External threads may have the crest corners chamferedat an angle of 45 deg with the axis to a maximumdepth of P/15.This corresponds to a maximum widthof chamfer flat of 0.0945P.
The internal and external threads may have optionafillets; see Fig. 3.
2.7 Basic Thread Form Dimensions
The basic dimensions of the Acme thread form forthe most generally used pitches are given in Table 1The basic thread profile is symmetrical and is illustratedin Fig. l. Design profiles are shown in Fig. 2
2.8 General Purpose Standard Acme ThreadSeries
A selected series of diameters and associated pitchetof Acme threads,listed in Table 2,are recommendedas preferred. These diameters and pitches have beencarefully selected to meet present needs with the fewestnumber of items in order to reduce to a minimum theinventory of both tools and gages. For sizes over 5in,see Appendix H.
ASME B1.5:1997 pdf download
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