MS internal wrenching bolts (superseding NAS series) are offered as part of AVIATIONEU NEW ERA product lines. Sourced from quality producers, they are fabricated from 160-180 ksi high-strength steel and are intended for use in both tension and shear applications. Standard AN hex head bolts and washers cannot be substituted for them as they do not have the required strength. NAS 144 to 158 series are supeseded by MS 20004 to MS 20024 series. Refer to the supersedure chart provided.
These bolts are available in different total and grip lengths, thread pitches and diameters in inches as well as with drilled or undrilled heads and shanks. The head of the internal wrenching bolt is recessed to allow the insertion of an internal wrench when installing or removing the bolt. When they are used in steel parts, the bolt hole must be slightly countersunk to seat the large corner radius of the shank at the head. In Dural material, a special heat-treated washer must be used to provide an adequate bearing surface for the head. They should always be used with the designed companion washer MS20002C(size) under the head as these bolts have a noticeable radius at the head to shank juncture. Special high-strength nuts are used on these bolts. To develop full tension use an NAS1804-(size) 180ksi, or an MS21042-(size) 160ksi nut according to your requrements.
Unless specified by the following letters in the part numbers, internal wrenching bolts come with an Undrilled Shank and Undrilled Head.
"A" Drilled Shank (NAS series)
"DH" Drilled Head (NAS series)
"ADH" Drilled Shank, Drilled Head (NAS series)
"H" Drilled Head (MS series)
Use these bolts with companion washers MS20002C(size) under the head and NAS1804-(size) 180ksi, or MS21042-(size) 160ksi high-strength nuts according to requrements.