ASME B18.29.2M:2005 pdf download

ASME B18.29.2M:2005 pdf download Helical Coil Screw Thread Inserts: Free Running and Screw Locking (Metric Series)
ASTM B 209M,Standard Specification for Aluminumand Aluminum Alloy Sheet and Plate
ASTM E 290,Standard Test Method for Bend Testing ofMaterial for Ductility
ASTM A 370,Standard Test Methods and Definitionsfor Mechanical Testing
ASTM F 568M,Carbon and Alloy Steel ExternallyThreaded Metric Fasteners
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4TERMINOLoGY
For definitions of terms relating to fasteners or compo-nent features thereof used in this Standard, refer toASME B18.12.
5 DIMENSIONS
(a)Unless otherwise stated, all dimensions in thisStandard are in millimeters and apply before any coat-ing. When plating or coating is specified, the finishedproduct dimensions shall be as agreed upon by the sup-plier and purchaser.
(b) Symbols specifying geometric characteristics arein accordance with ASME Y14.5M.
6DESCRIPTION
Helical coil inserts are screw thread bushings coiledfrom wire of diamond-shape cross-section. Inserts arescrewed into STI-tapped holes to form nominal sizeinternal threads.Inserts are installed by torquingthrough a diametral tang. This tang is notched forremoval after installation. In the free state, they are largerin diameter than the tapped hole into which they are installed. In the assembly operation, the torque appliedto the tang reduces the diameter of the leading coil andpermits it to enter the tapped thread. The remainingcoils are reduced in diameter as they, in turn, are screwedinto the tapped hole. When the torque or rotation isstopped, the coils expand with a spring-like actionanchoring the insert in place against the tapped hole.
7 CLAss OF FIT
7.1 Tolerance Classes 4H5H and 5H
Since helical coil inserts are flexible, the class of fit ofthe final assembly is a function of the size of the tappedhole.Helical coil STI taps are available for both ToleranceClass 4H5H- (or Class 4H6HI-) and Class 5Hl-tappedholes.Tolerance Class 5H-tapped holes provide maxi-mum production tolerances but result in lower lockingtorques when screw-locking inserts are used. The higherand more consistent torques given in Table 5 are metby the screw-locking inserts when assembled and testedin Tolerance Class 4H5H-(or Class 4H6H-) tapped holesin accordance with para.9.
7.2 Compatibility
Assembled helical coil inserts will mate properly withitems that have M Profile external threads in accordancewith ASME B1.13M.Also, due to the radius on the crestof the insert at the minor diameter, the assembled insertwill mate with MJ Profile externally threaded parts withcontrolled radius root threads per ASME B1.21M.
8TYPES OF INSERTS
8.1 Free-Running
The free-running insert provides a smooth, hard, andfree-running thread.
8.2 Screw-Locking
The screw-locking insert provides a resilient lockingthread produced by a series of chords on one or moreof the insert coils.
9 STI-TAPPED HOLE
The tapped hole into which the insert is installed shallbe in accordance with ASME B1.13M, except that diame-ters are larger to accommodate the wire cross-section ofthe insert (see Fig.1). Dimensions of the STl-tapped holeare shown in Table 1 and are calculated per GeneralNote (c) to Table 1.
9.1 Screw Thread Designation
9.1.1 Designation for Tapped Hole.The drawing notefor the STI-threaded hole per Table 1 to accept the helicalcoil insert shall be in accordance with the followingexample:
EXAMPLE: M8 × 1.25-5H STI; 23.5 T per ASME B18.29.2M.
9.1.2 Designation for a Helical Coil Insert
(a) Helical coil inserts shall be designated by the following data, in the sequence shown:
(1) product name
(2) designation of the standard
(3) nominal diameter and thread pitch
(4) nominal length
(5) insert type (free-running or screw-locking)