1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2015 SAE International All rights reserved. No part of this p
3、ublication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/MAP4296 AEROSPACE RECOMMENDED PRACTICEMAP4296 Issued 1993-06 Reaffirmed 2015-08 D
5、rawing Interpretations, Standard Machining Practice, Tube Fittings and Connectors, Fluid Systems, Metric RATIONALE MAP4296 has been reaffirmed to comply with the SAE five-year review policy. 1. SCOPE:This SAE Metric Aerospace Recommended Practice (MAP) establishes the drawing interpretations,standar
6、d machining practice for tube fittings and connectors used in metric fluid systems.1.1 Product Classification: This MAP is intended to interpret and clarify engineering drawing requirements relating to the manufacture and inspection of fluid tube fittings and connectors. Because it is impractical to
7、 define every minute detail of the part on the face of the drawing, this document describes general machining tolerances that fall under the heading of, “good shop practice“. This document serves as a supplement to engineering drawings when referenced on applicable documents.2. REFERENCES:2.1 Applic
8、able Documents: The following publications form a part of this specification to the extent specified herein. The latest issue of all SAE Technical Reports shall apply.2.1.1 ANSI/ASME Publications: Available from the American Society of Mechanical Engineers, 345 East 47th Street, New York, NY 10019.A
9、NSI/ASME B46.1 Surface TextureANSI Y14.5M Dimensioning and Tolerancing3. TECHNICAL REQUIREMENTS:3.1 General: 3.1.1 Conflict in Requirements: Where a conflict exists between the requirements of this document and the applicable part drawing, the part drawing shall take precedence.SAE INTERNATIONAL MAP
10、4296 Page 2 of 7 3.1.2 Burrs and Sharp Edges: Finished parts are to have all burrs and slivers removed. Break edges 0.08 to 0.38 mm unless otherwise noted.3.1.3 Dimensioning and Tolerancing: The rules, principles and methods of dimensioning and tolerancing used to define the required configuration a
11、re contained in ANSI Y14.5M.3.1.4 Titanium: When machining and cleaning titanium or titanium alloys, cutting fluids and compounds must not contain chlorides or fluorides.3.2 Tolerances: 3.2.1 Concentricity: See 3.2.5.3.2.2 Angularity: 3.2.2.1 Shapes: Angularity between the legs of shape fittings suc
12、h as tees, elbows, and crosses shall be as shown in Figure 1.FIGURE 1 - Angularity Tolerance Between Legs of Shape Fittings3.2.3 Drilled Holes: 3.2.3.1 Tolerance: For drilled holes without a specified size limit, the tolerances noted in Table 1 shall apply.SAE INTERNATIONAL MAP4296 Page 3 of 7 TABLE
13、 1 - Hole Size Tolerance3.2.3.2 Pilot Drill Size and Depth: The pilot drill size for a reamed or bored hole is generally not specified on the engineering drawing. Unless otherwise noted, the drilled hole may be smaller than the finished machined hole by not more than 0.8 mm. The depth of the reamed
14、or bored hole shall be within 0.8 mm of the drilled hole depth. See Figure 2.FIGURE 2 - Pilot Hole Size and Depth3.2.3.3 Drill Point: For conventional twist drills, the drill point included angle shall be 90 minimum.3.2.3.4 Runout: The angular runout from true center for fluid passage holes shall be
15、 as shown in Figures 3 and 4. The allowable drill runout is in addition to the angle tolerance specified on the drawing.FIGURE 3 - Fluid Passage Hole Runout of Shape FittingsSAE INTERNATIONAL MAP4296 Page 4 of 7 FIGURE 4 - Fluid Passage Runout of Straight Fittings3.2.4 Perpendicularity: Unless other
16、wise specified, machined surfaces shown on engineering documents as being at right angles to each other shall be perpendicular within 030.3.2.5 Eccentricity and Circularity (Roundness): The physical condition generally known as concentricity is sometimes controlled on engineering drawings by the app
17、lication of the “runout“ or “position“ symbols. Any reference to concentricity in this document shall be interpreted to include callouts of “runout“ and “position“ as they are applied to control eccentricity.3.2.5.1 Circularity Tolerance: The circularity (roundness) tolerance of a machined diameter
18、shall not exceed 0.013 mm plus one-quarter the diametrical tolerance and must fall within the limits of maximum material and minimum material conditions as shown in the example in Table 2.TABLE 2 - Example of Circularity Tolerance3.2.5.2 Runout, Diameter on Common Centerline (see Tables 3 and 4): Th
19、e maximum FIM between two machined diameters on a common centerline shall be one-half the sum of the tolerances of the two diameters. If the resultant value from the calculation is less than 0.08 mm, the maximum allowable FIM shall be held to 0.08 mm.SAE INTERNATIONAL MAP4296 Page 5 of 7 TABLE 3 - R
20、unout of Diameter on Common CenterlineExample ATABLE 4 - Runout of Diameter on Common CenterlineExample BSince the resultant value is less than 0.08 mm, the maximum allowable FIM shall be held to 0.08 mm.3.2.5.3 Eccentricity of Machined Diameters and Stock Size: The maximum eccentricity between mach
21、ined diameters and stock size surfaces shall be 0.38 mm.3.2.6 Machining: 3.2.6.1 Surface Texture: Symbols shall be per ANSI Y14.36 and requirements shall conform to ANSI/ASME B46.1. Unless otherwise specified, surfaces shall be 3.2 m Ra. Drilled holes, hex flats, and wrench pads shall not exceed 6.4
22、 m Ra.3.2.6.2 Flaws: Flaws are defined in this document to be dents, scratches, and other local damage visible with the unaided eye caused by unintentional surface contact with another item or surface. Acceptance or rejection of a part containing flaws is dependent upon the function of the part and
23、the criticality of the affected surface. Flaws on sealing surfaces or other critical type surfaces should be controlled on individual engineering drawings.3.2.6.3 Mismatch: Unless otherwise noted, when two machined surfaces intersect, the misalignment between these surfaces shall not exceed 0.25 mm.
24、 The minimum fillet radius at the junction of these surfaces shall be 3 mm. The intersection of the surfaces shall be blended and faired where necessary to avoid abrupt changes.3.2.6.4 Screw Threads: Unless otherwise specified on the engineering drawing, screw threads shall conform to requirements n
25、oted below.3.2.6.4.1 Features: Thread feature such as major, minor, and pitch diameters, root radii, etc. shall conform to the sizes given in the applicable thread standard.SAE INTERNATIONAL MAP4296 Page 6 of 7 3.2.6.4.2 Chamfers and Countersinks: Threads must be chamfered or countersunk as shown in
26、 Figure 5 unless otherwise specified on the engineering drawing.FIGURE 5 - Tolerance of Thread Chamfers and Countersinks3.2.6.4.3 Lengths: Thread length as specified on an engineering drawing shall be understood to mean that the part must accept the thread gage to the dimension noted.3.2.6.5 Holes:
27、Holes shown on engineering drawings normally do not define the methods to be used in producing the hole. While the drawing may, in some instances, imply that a hole is drilled by showing a drill point or by calling a drill depth, the manufacturing department has the option to use other machining met
28、hods provided the finished hole conforms to the dimensions shown on the drawing. Unless otherwise specified, the bottom of the hole may have a curved or conical contour.3.2.6.5.1 Depths: The specified depth of a hole is to be interpreted as the depth of the full diameter of that hole.3.2.6.6 Spotfac
29、ing: Shall be interpreted as noted below.3.2.6.6.1 Machined Faces: On machined faces, the depth of the spotface shall not be greater than 0.8 mm.3.2.6.6.2 Forged Faces: On forged faces, the depth of the spotface shall not be greater than 1.5 mm.3.2.6.6.3 Hole and Thread Depth: When a spotface callou
30、t is used in conjunction with drilled or threaded holes, the depths are to be measured from the spotface surface.3.2.6.6.4 Fillet Radii: Fillet radii for spotface machining shall be 0.25 to 0.5 mm unless otherwise specified.SAE INTERNATIONAL MAP4296 Page 7 of 7 3.2.7 Break Edge Interpretation: 3.2.7
31、.1 Profile: The note, Break Edge .XX-.XX, shall be interpreted as requiring a profile that:a. Will be convex or flat or a combination of bothb. Will be blended into adjoining surfacesc. Will be wholly (including blends) within a tolerance zone defined by the limits specified in the note as shown in Figure 6FIGURE 6 - Break Edge Tolerance ZonePREPARED BY SAE COMMITTEE G-3, AEROSPACE COUPLINGS,FITTINGS, HOSE, AND TUBING ASSEMBLIES
