DIN 975 or DIN 976-1? How to specify threaded rod on a purchase order

Threaded rod is simple to make and easy to order wrongly. Most problems come from a missing standard, a missing property class, or galvanized rod ordered without matching nuts.

DIN 975 and DIN 976-1

DIN 975 (1986) is listed by DIN as withdrawn, with the title note "not intended for new designs". DIN 976-1, in its 2016 edition, is current, and the fastener trade treats it as the replacement. Both still appear on drawings and purchase orders, so say which one your drawing names. There is no ISO product standard for threaded rod.

Write the order line in this order

Product, standard, size × length, property class, finish. For example:

Threaded rod DIN 976-1 – M12 × 1000 – 8.8 – zinc plated

Leaving out the class is the most common gap: class 4.8 and class 8.8 rod differ in strength, price and lead time.

Hot-dip galvanized rod needs oversize nuts

Hot-dip galvanizing adds a thick coating to the thread. ISO 10684 handles this by tapping the nuts oversize, to tolerance class 6AZ or 6AX after coating, to mate with the galvanized external thread. Such nuts are marked with Z or X after the property class. Order the nuts with the rod so the two match.

Inch rod: order by ASTM specification

• ASTM A193 grade B7: alloy steel bolting for pressure vessels, valves, flanges and fittings in high-temperature or high-pressure service.
• ASTM A307 grade A: bolts, studs and threaded rod with a minimum tensile strength of 60 ksi, for general applications.
• ASTM F1554 (grades 36, 55 and 105): anchor bolts for fixing structural supports to concrete foundations, including all-thread rod used for anchoring.

Before you send the enquiry

Use the weight calculator to estimate freight, and the size chart for pitch and stress area. Then send the order line, the quantity and length per piece, and the documents you need with the shipment.