Are SAE Grade 2, 5, and 8 bolts available in diameters over 1½"?
No, the SAE J429 specification only covers bolts up to and including 1½” diameter. SAE J429 (1999), the specification that includes Grade 2, 5, and 8 fasteners, states:
“This SAE standard covers the mechanical and material requirements for inch-series steel bolts, screws, studs, SEMS, and U-bolts used for automotive and related industries in sizes to 1½ in. inclusive.”
Consequently, there are no defined dimensional, chemical, or strength requirements for Grade 2, 5, or 8 bolts larger than 1½” diameter. They simply do not exist and cannot be manufactured. We are shocked at the frequency in which SAE J429 bolts are sold in 1¾”, 2”, 2¼” and 2½” diameters. Anyone buying, selling, or installing these large diameter SAE fasteners are exposing themselves and their organization to a tremendous amount of liability. One should also question the competence of any fastener manufacturer or distributor claiming to sell SAE J429 Grades 2, 5, or 8 fasteners larger than 1½” diameter.
When diameters larger than 1½” are required, ASTM specifications should be considered since many cover fasteners larger than 1½” diameter. Generally speaking, for construction applications ASTM is the most appropriate standard. SAE is more commonly specified for automotive, equipment, or machinery applications.
When SAE grades over 1½” diameter have been specified, an obvious mistake has been made, and it is important to work with your customer, contractor, or the Engineer of Record to rectify the error and determine the appropriate grade based on diameter, application, strength, and chemistry. This Strength Requirement by Grade Chart can assist in determining the appropriate grade of fastener when diameters larger than 1½” are required.