Q: What is the difference between NAS1351 and NAS1352? Aren’t they both socket head cap screws?
A: Yes, both NAS1351 and NAS1352 are both socket head cap screws. The primary difference is the threads. NAS1351 pertains to socket head cap screws with a coarse thread pitch, whereas NAS1352 applies to only fine thread pitch fasteners. Both of these numbers provide specifications (such as material, coatings, etc.) per the National Aerospace Standards (NAS).