SS304 Round Bend Clamp U Bolt 

ASME, a global standards organization, provides dimensional guidelines and dimensional tolerances for a wide variety of fasteners and related items. Bent bolts, such as 90-degree bend anchor bolts, U bolts and eye bolts, fall under ASME B18.31.5. ASME B18.31.5 provides information regarding tolerances and quality, and their drawings also indicate where the bolts should be measured from when they are being specified. For instance, the below drawing shows where ASME (and Portland Bolt) will measure a bent anchor bolt, and it’s from inside dimensions. Similarly, U-bolts are measured from inside dimensions: