Seller: stlhardware (4,178) 99.9% , Location: Saint Louis, Missouri, Ships to: US & many other countries, Item: 391626766007 Qty. 25 - vintage square head machine bolts 5/16-18 x 1 3/4" with square nuts - steel plain finish - thread length is 1 1/2" - surface rust on the bolts and the threads and the nuts - the machine bolts with square nuts will come packaged in a zip lock bag. I do not know the grade as these are unmarked. New old stock from an oldtime hardware store. Condition: New old stock - surface rust on the bolts and the threads and surface rust on nuts - machine bolts with nuts and will come in a zip lock baggie - these are not marked so I do not know the grade, Fastener Type: Machine Bolt with Nut, Drive Type: Wrench, Head Style: Square, Coating: Plain, Grade: unknown, Material: Steel, Thread Diameter (in.): 5/16-18, Length (in.): 1 3/4", Brand: Unbranded/Generic, Country/Region of Manufacture: Unknown, Model: Square Head Machine Bolt, MPN: Does not apply, Quantity: 25, Thread Length: 1 1/2"