ASME B18.29.1 pdf download

ASME B18.29.1 pdf download Helical Coil Screw Thread Inserts— Free Running and Screw Locking (Inch Series)
1.4 Class of Fit 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 both tolerance Classes 2B and 3B tapped holes. Tolerance Class 2B tapped holes provide maximum 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 in tolerance Class 3B tapped holes in accordance with section 2.
1.5 Compatibility Assembled helical coil inserts will mate properly with items having UN external threads in accordance with ASME B1.1. In addition, due to the radius on the crest of the insert at the minor diameter, the assembled insert will mate with UNJ profile external threaded parts with controlled radius root threads per SAE AS8879.
1.6 Types of Inserts
1.6.1 Free-Running. The free-running insert pro- vides a smooth, hard, and free-running thread.
1.6.2 Screw-Locking. The screw-locking insert pro- vides a resilient locking thread produced by a series of chords on one or more of the insert coils.
2 STI TAPPED HOLE The tapped hole into which the insert is installed shall be in accordance with ASME B1.1, except that diameters are larger to accommodate the wire cross-section of the insert. Dimensions of the STI tapped holes are shown in Table 1 and calculated per Note (3) of Table 1.
2.1 Screw Thread Designation
2.1.1 Designation for Tapped Hole. The drawing note for the STI threaded hole per Table 1 to accept the helical coil insert shall be in accordance with the following example: EXAMPLE: 1 ⁄ 4 -20 UNC-2B STI thread 0.430 min. depth, per ASME B18.29.1.
2.1.2 Designation for a Helical Coil Insert. Designa- tion of the helical coil insert on parts lists, spares lists, purchase orders, etc., shall be in accordance with the following examples:
EXAMPLES:
(1) ASME B18.29.1, 1 ⁄ 4 -20 UNC 0.375 long helical coil free-running insert.
(2) ASME B18.29.1, #10-32 UNF 0.380 long helical coil screw-locking insert.
2.1.3 Designation for STI Threaded Hole Including Installed Helical Coil Insert. The drawing note for the STI threaded hole per Table 1, having a helical coil insert installed, shall be in accordance with the following example:
EXAMPLES:
(1) 1 ⁄ 4 -20 UNC-2B STI thread 0.430 deep.
(2) ASME B18.29.1, 1 ⁄ 4 -20 UNC 0.375 long helical coil free-running insert.
2.2 Gages and Gaging Acceptance of the threaded hole is determined by gaging with STI GO, NOT GO (HI), and plain cylindrical gages designed and applied in accordance with System 21 of ASME B1.3 (see Nonmandatory Appendix C).