ASME B18.2.9:2007 pdf download Straightness Gage and Gaging for Bolts and Screws
1 SCOPE
This Standard describes a gage and procedure forchecking bolt or screw straightness at maximum material condition (MMC).
2 COMPARISON WITHISO 4759-1:2000
This Standard uses an adjustable gage, instead of plainsleeve gages like the example shown in ISO 4759-1Annex C, Figure C.24. The adjustable gage avoids thenecessity of a different gage for each diameter-lengthcombination,and for each difference in the specifiedtolerances on diameter and/or straightness of the fastener.
REFERENCED STANDARDS3
For undated references, the most recent issues of thereferenced standards apply.ASME B18.12，Glossary of Terms for Mechanical Fas-tenersASMEY145M,Dimensioning and TolerancingPublisher: The American Society of Mechanical Engineers (ASME)，Three Park Avenue，New York，NY10016-5990;Order Department: 22 Law Drive，POBox 2300,Fairfield,N 07007
ISO 4759-1:2000 Tolerances for fasteners – Part 1: BoltsScrews, Studs and Nuts – Product Grades A, B, and CPublisher: International Organization for Standardization (ISO),1. ch. de la Voie-Creuse, Case Postale 56CH-1211 Geneve 20,Switzerland/Suisse
4 TERMINOLOGY
For definitions of terms relating to fasteners or features thereof used in this Standard,refer to ASME B1812
DIMENSIONS
For definitions of terms relating to dimensioning andtolerancing, refer to ASME Y145M.
GAGE
The gage consists of a stationary rail, an adjustablerail, micrometers that indicate the distance between therails at each end, and a means to secure the adjustablerail in place. A typical gage is illustrated in Fig. 1.
7 PROCEDURE
(a) The excluded length, illustrated in Fig. 2, is thelength, if any, that is to be excluded from the straightnessgage, as specified by the product standard.(b) The gaged length, illustrated in Fig. 2, is calculatedas the bolt or screw length minus the excluded length(c) The straightness tolerance at MMC for the productto be inspected is calculated for the gaged length by theformula specified in the product standard.
(d) The resultant condition is calculated as the largerof the maximum major diameter of the thread or themaximum body diameter of the bolt or screw, plus thestraightness tolerance at MMC.
(e) The adjustable rail of the gage is adjusted to provide a parallel space between the rails equal to the resultant condition by obtaining common readings on bothmicrometer heads, and is secured in place.
(f) The gaged length of the product to be inspectedis inserted between the rails, then rotated by handthrough a full 360 deg. Any interference occurringbetween the product and the gage sufficient to preventrotation indicates that the specified straightness is notmet.