SAE AS 7250D:2013 pdf free

SAE AS 7250D:2013 pdf free.Nuts, Self-Locking, Steel, Corrosion and Heat Resistant High Strength, All Metal 1200 °F Use, UN Thread Form
Each nut shall be a self-contained unit including the self-locking device. The locking device shall not operate by means of separate movement from the installation and shall not depend on pressure on the bearing surface for the locking action. The locking device shall be set to meet the locking torque requirements of 3.9.3 when used with external threads that meet the requirements of 3.9. Tool marks resulting from producing the locking feature shall blend smoothly without abrupt change.
The bearing surface shall be square (flat to concave) with the thread pitch cylinder axis within the limits specified on the part drawing. Bearing surface shall not be convex. Bearing surface squareness shall be tested using a table squareness gage and feeler gage. The squareness requirement shall apply to the complete bearing surface of the nut except that, for nonfloating plate nuts having a bearing surface exceeding 1.5 times the thread major diameter, the squareness requirement shall, unless otherwise specified on the part drawing, apply only to the portion of the bearing surface of the nut contained within a diameter equal to 1.5 times the thread major diameter. The nuts to be inspected shall permit at least three complete turns of engagement on the thread arbor of the squareness gage; plating or coating may be stripped,if necessary, to meet this requirement. Multipiece floating plate nuts shall have the nut element removed from the retainer for checking thread squareness.
This test is applicable to wrenching nuts with hexagon or double hexagon wrenching feature. For this test only, all nuts shall be cleaned to remove all trace of any lubricant, wax, or antiseize coating or compound. At least three nuts shall be tested at room temperature for wrench torque by assembling a nut on an alloy steel bolt having sufficient strength. The nut shall be tightened against a bushing with a hole diameter as in 3.9.1 and having hardness not lower than 40 HRC, and surface roughness of 63 μin Ra. Nuts shall withstand 12 successive applications of the torque specified in Table 2 without destroying the wrenchability of the nut. Wrenches used for this test can be open ended type or socket type.SAE AS 7250D pdf free download.