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)
1 GENERAL
1.1 Scope This Standard delineates the dimensional, mechani- cal, and performance data for the metric series helical coil screw thread insert and threaded hole into which it is installed. Appendices that describe insert selection, STI (screw thread insert) taps, insert installation, and removal tooling are also included. The inclusion of dimensional data in this Standard is not intended to imply that all products described are stock sizes.
2 COMPARISON WITH ISO STANDARDS
At this time, no ISO Standard for metric helical coil screw threads exists. Further, no work within ISO is expected for some time.
5 DIMENSIONS
(a) Unless otherwise stated, all dimensions in this Standard are in millimeters and apply before any coat- ing. When plating or coating is specified, the finished product dimensions shall be as agreed upon by the sup- plier and purchaser. (b) Symbols specifying geometric characteristics are in accordance with ASME Y14.5M.
6 DESCRIPTION
Helical coil inserts are screw thread bushings coiled from wire of diamond-shape cross-section. Inserts are screwed into STI-tapped holes to form nominal size internal threads. Inserts are installed by torquing through a diametral tang. This tang is notched for removalafterinstallation. Inthe free state, theyarelarger in diameter than the tapped hole into which they are installed. In the assembly operation, the torque applied to the tang reduces the diameter of the leading coil and permits it to enter the tapped thread. The remaining coils are reduced indiameter as they, inturn, are screwed into the tapped hole. When the torque or rotation is stopped, the coils expand with a spring-like action anchoring 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 of the final assembly is a function of the size of the tapped hole. Helical coil STI taps are available for bothTolerance Class 4H5H– (or Class 4H6H–) and Class 5H–tapped holes. Tolerance Class 5H–tapped holes provide maxi- mum production tolerances but result in lower locking torques when screw-locking inserts are used. The higher and more consistent torques given in Table 5 are met by the screw-locking inserts when assembled and tested inTolerance Class 4H5H–(or Class 4H6H–) tapped holes in accordance with para. 9. 7.2 Compatibility Assembled helical coil inserts will mate properly with items that have M Profile external threads in accordance with ASME B1.13M. Also, due to the radius on the crest of the insert at the minor diameter, the assembled insert will mate with MJ Profile externally threaded parts with controlled radius root threads per ASME B1.21M.
10 HELICAL COIL INSERT
10.1 Material Chemical composition of the inserts is austenitic corrosion-resistant (stainless) steel within the limits of Table 2. 10.2 Properties 10.2.1 Tensile Strength. Wire, before coiling into inserts, shall have tensile strength not lower than 1035 MPa, determined in accordance with ASTM A 370. 10.2.2 Bending. Wire shall withstand, without crack- ing, bending in accordance with ASTM E 290 at room temperature through an angle of180 deg around a diam- eter equal to twice the cross-sectional dimension of the wire in the plane of the bend. 10.2.3 Workmanship. The formed wire shall be of uniform quality and temper; it shall be smooth, clean, and free from kinks, waviness, splits, cracks, laps, seams, scale, segregation, and other defects that may impair the serviceability of the insert.