ASME B18.29.2M pdf download Helical Coil Screw Thread Inserts: Free Running and Screw Locking (Metric Series)
1 0 HELICAL COIL INSERT be the avoidance of bridging between coils. Slight fill- in between closely wound coils, which immediately sep1 0.1 Material Chemical composition of the inserts is austenitic corrosion-resistant (stainless) steel within the limits of Table 2.
1 0.2 Properties
1 0.2.1 Tensile Strength. Wire, before coiling into inserts, shall have tensile strength not lower than 1 035 MPa, determined in accordance with ASTM A 370.
1 0.2.2 Bending. Wire shall withstand, without crack- ing, bending in accordance with ASTM E 290 at room temperature through an angle of 1 80 deg around a diam- eter equal to twice the cross-sectional dimension of the wire in the plane of the bend.
1 0.2.3 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. arates as the coils are axially pulled apart by hand, shall not be considered bridging.
1 0.4 Configuration and Dimensions Insert configurations shall be in accordance with Fig. 2, and dimensions shall be in accordance with Tables 3 and 4.
1 0.4.1 Nominal Length. Each nominal insert size is standardized in five lengths, which are multiples of the insert’s nominal diameter. These are 1 , 1 .5, 2, 2.5, and 3 times nominal diameter. Each nominal length is the minimum through-hole length (material thickness), without countersink, into which that insert can be installed. The nominal insert length is a reference value and cannot be measured.
1 0.4.2 Assembled Length. Actual assembled length of the insert equals nominal length minus 0.5 pitch to minus 0.75 pitch, with insert installed in a basic STI- threaded hole. It cannot be measured in the insert’s free state. 1 0.3 Coatings 1 0.3.1 Dry Film Lubricant Coating. At the option of the user, dry film lubricant coating can be applied to 1 1 INSPECTION AND QUALITY ASSURANCE helical coil inserts. The coating shall meet the require- ments of paras. 1 0.3.1 .1 and 1 0.3.1 .2. The color of dry film– lubricated inserts is dark gray to black.
1 0.3.1.1 Material. The lubricant shall meet the requirements of Aerospace Standard SAE AS5272, Type I, Lubricant, Solid Film Heat Cured, and Corrosion Inhibiting.
1 0.3.1 .2 Thickness. The coating shall be uniformly deposited on the insert with the minimum thickness being complete coverage. The maximum thickness shall 5 Unless otherwise specified by the purchaser, the inspection of inserts shall be in accordance with ASME B1 8.1 8.1 M, with inspection level 3 for the 1 5- cycle torque test described in para. 1 1 .2.3.
1 1.1 Inspection (Nondestructive)
1 1.1 .1 Examination of the Product. Inserts shall be visually examined for conformance with drawings and workmanship requirements in accordance with ASME B1 8.1 8.1 M.
11.1 .2 Threads. The inserts, when assembled in STI- threaded holes conforming to Table 1 , shall form threads conforming to ASME B1 .1 3M Tolerance Class 4H5H or 5H except for the locking feature of screw-locking inserts. The assembled insert, both types, shall accept and function with parts having external MJ threads per ASME B1 .21 M. NOTE: The accuracy of the finished thread when the insert is installed depends on the accuracy of the tapped hole. If the finished tapped hole gages satisfactorily, the installed insert will be within the thread tolerance when the insert meets the requirements of the Standard. It is, therefore, not necessary to gage the installed insert. After the insert is installed, the GO thread plug gage may not enter freely because the insert may not have been fully seated in the tapped hole. However, the insert should become seated after a bolt or screw is installed and tightened.
11.1.3 Tang Removal Notch. The tang removal notch shall be located as shown in Fig. 2 and of such depth that the part may be installed without failure of the tang and that the tang may be removed, after assembly, without affecting the function of the installed insert.
1 1.2 Self-Locking Torque (Destructive) The screw-locking insert, when assembled in threaded holes conforming to Table 1 and tested in accordance with the following paragraphs, shall provide a frictional lock to retain the bolt threads within the torque limits specified in Table 5.
1 1.2.1 Torque Test Bolts. Assembled screw-locking inserts shall be torque tested with bolts in accordance with ASME B1 .1 3M or ASME B1 .21 M, cadmium plated, or having other coating with a similar coefficient of fric-on and hardness of 36 HRC to 44 HRC. The bolts selected for this test shall be of sufficient length so the thread runout does not enter the insert and that a mini- mum of one full thread extends past the end of the insert when the bolt is fully seated. Acceptability of bolt threads shall be determined based on System 22 of ASME B1 .3M.