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 entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro
2、m, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.Copyright 2004 SAE InternationalAll rights reserved. No part of this publication may be
3、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: 724-776-4970 (outside USA)Fax: 724
4、-776-0790Email: custsvcsae.orgSAE WEB ADDRESS: http:/www.sae.orgAEROSPACE RECOMMENDED PRACTICEARP4296REV.AIssued 1990-08Revised 1999-01Reaffirmed 2004-04Supersedes ARP4296(R) Drawing Interpretation and Standard Machining Practices,Couplings, Fittings and Hose Ends, Fluid Systems1. SCOPE:This SAE Aer
5、ospace Recommended Practice (ARP) is intended to interpret and clarify engineering drawing requirements relating to the manufacture and inspection of fluid system couplings, tube fittings, and hose ends. Because it is impractical to define every minute detail of the part on the face of the drawing,
6、this document describes interpretations of dimensioning of general machining features and otherwise undefined 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. APPLICABLE DOCUMENTS:T
7、he following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase order. In the event of conflict between the text of this docume
8、nt and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.2.1 SAE Publications:Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.ARP4266 H
9、ole Contour, Fluid Passage, Tube FittingARP4784 Definitions and Limits, Metal Material Defects and Surface and Edge Features, Fluid Couplings, Fittings and Hose Ends2.2 ANSI/ASME Publications:Available from ASME, 22 Law Drive, Box 2900, Fairfield, NJ 07007-2900.ASME Y14.5M Dimensioning and Toleranci
10、ngCopyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP4296 Revision A- 2 -3. REQUIREMENTS:3.1 General:3.1.1 Conflict in Requirements: Where a conflict exists between the requirements of this docum
11、ent and the applicable part drawing, the part drawing shall take precedence. All requirements herein are meant to apply only if not specified on the drawing.3.1.2 Material Defects and Surface and Edge Flaws: Unless specified on the drawing surface and edge defect definitions and limits shall be in a
12、ccordance with ARP4784.3.1.3 Sharp Edges: Break edges 0.003 to 0.015 unless otherwise noted.3.2 Tolerances:3.2.1 Concentricity: Unless there is a definite need for the control of a features median points, it is recommended in ANSI Y14.5M-1982 or ASME Y14.5M-1994 that a control be specified in terms
13、of a runout tolerance (see 3.2.6) or a positional tolerance.3.2.2 Angularity:3.2.2.1 Shapes: Angularity between the legs of shape fitting such as tees, elbows, and crosses shall be as shown in Figure 1.FIGURE 1 - Angularity of Shape FittingsCopyright SAE International Provided by IHS under license w
14、ith SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP4296 Revision A- 3 -3.2.3 Holes:3.2.3.1 Offset: The allowable fluid passage hole offset, on holes depicted as collinear on the drawing but machined from opposite directions, shall be 0.015 maximum (see F
15、igure 2).FIGURE 2 - Runout of Fluid Passage Holes, Straight Fittings3.2.4 Circularity Tolerance: The circularity (roundness) tolerance of a machined diameter shall not exceed 0.0005 plus one-quarter of the diametrical tolerance and must fall within the limits of maximum material and minimum material
16、 conditions as shown in the example in Table 1.This requirement is not applicable to diameters on thin wall cylinders where the wall thickness is less than 2.5% of the ID.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without l
17、icense from IHS-,-,-SAE ARP4296 Revision A- 4 -3.2.5 Circular Runout, Diameters on Common Centerline (see Tables 2 and 3): The 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 calculati
18、on is less than 0.003, the maximum allowable FIM shall be held to 0.003.Since the resultant value is less than 0.003, the maximum allowable FIM shall be held to 0.003.This requirement is not applicable to diameters on thin wall cylinders where the wall thickness is less than 2.5% of the ID.TABLE 1 -
19、 Circularity ToleranceMaximum limit = 0.880Minimum limit = 0.870Diametrical tolerance = 0.0101/4 tolerance = 0.0025Additional tolerance = 0.0005Total tolerance = 0.003TABLE 2 - Circular Runout, Example ADiameter A is 0.490/0.510 tolerance = 0.020Diameter B is 0.621/0.629 tolerance = 0.008Tolerance s
20、um = 0.0281/2 tolerance sum = 0.014Runout = 0.014 (FIM)TABLE 3 - Circular Runout, Example BDiameter A is 1.2119/1.2125 tolerance = 0.0015Diameter B is 0.7225/0.7250 tolerance = 0.0025Tolerance sum = 0.0041/2 tolerance sum = 0.002Copyright SAE International Provided by IHS under license with SAENot f
21、or ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP4296 Revision A- 5 -3.2.6 Machining:3.2.6.1 Threads: Unless otherwise specified on the engineering drawing, threads shall conform to requirements noted below.3.2.6.1.1 Chamfers and Countersinks: Threads shall be cha
22、mfered or countersunk as shown in Figure 3 unless otherwise specified on the engineering drawing.FIGURE 3 - Thread Chamfer3.2.6.1.2 Thread Lengths: Thread length as specified on an engineering drawing shall be understood to mean that the part must comply with the thread specification requirements to
23、 the dimension noted.3.2.6.2 Holes: Holes shown on engineering drawings normally do not define the method 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 specifying a drill depth, the manufacturer has the option
24、to use other machining methods provided the finished hole conforms to the dimensions shown on the drawing. Other than elbow fittings, the bottom of the hole may have a curved or conical contour. Elbows shall have a spherical radius at the intersection of the two holes, as required in ARP4266. An und
25、efined conical contour in the bottom of a hole shall have a minimum included angle of 110.3.2.6.2.1 Depths: The specified depth of a hole is to be interpreted as the depth of the full diameter of that hole.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproductio
26、n or networking permitted without license from IHS-,-,-SAE ARP4296 Revision A- 6 -3.2.6.3 Spotfacing: Shall be interpreted as noted below.3.2.6.3.1 Machined Faces: On machining faces, the depth of the spotface shall not be greater than 0.030.3.2.6.3.2 Forged Faces: On forged faces, the depth of the
27、spotface shall not be greater than 0.060.3.2.6.3.3 Hole and Thread Depth: When a spotface callout is used in conjunction with drilled or threaded holes, the depths are to be measured from the spotface surface.3.2.6.4 Fillet Radii: Fillet radii for spotface machining shall be 0.010 to 0.020.3.2.7 Bre
28、ak Edge Interpretation: The note, Break Edge .XXX-.XXX, 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 not
29、e as shown in Figure 4.4. NOTES:4.1 The change bar ( l ) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates
30、a complete revision of the document.4.2 Dimensions:All dimensions are in inches.4.3 Key Words:Couplings, fittings, hose ends, machining, drawingsCopyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE ARP4296 Revision A- 7 -FIGURE 4 - Break Edge InterpretationPREPARED BY SAE COMMITTEE G-3, AEROSPACE COUPLINGS,FITTINGS, HOSE AND TUBING ASSEMBLIESCopyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
