What is a heavy hex bolt?
A heavy hex bolt has a larger hex head than a standard hex bolt of the same diameter. For example, a 1/2" heavy hex bolt takes a 7/8" wrench, while a standard 1/2" hex bolt takes a 3/4" wrench. The larger head gives more bearing surface. Heavy hex is the standard head for A325 and A490 structural bolts.
Choose the grade
- A325 structural bolts: heavy hex structural bolts from 1/2" to 1-1/4" diameter, plain or hot-dip galvanized. See all structural bolts.
- A490 heavy hex bolts: structural bolts from 5/8" to 1-1/4" diameter. A490 is a higher-strength structural grade than A325. A490 bolts are plain finish (A490 is not galvanized). Use the grade your drawings call for.
- B7 alloy steel: heavy hex bolts in B7 steel from 1/2" to 1-1/4", in partial-thread and full-thread versions. For threaded rod in the same grade, see B7 studs.
- A307 low carbon steel: general-purpose heavy hex bolts from 1/2" to 1-1/2", plain, zinc or hot-dip galvanized.
- Large diameters: alloy steel from 1-1/8" to 2-1/2", and Grade 5 at 2", in lengths up to 18".
- 18-8 stainless: 18-8 stainless, passivated (3/8" and 1/2").
Thread and size callouts
Heavy hex bolts are listed as diameter-threads per inch x length, for example 3/4"-10 x 3" or 1"-8 x 4". Most are coarse thread. Some larger sizes are 8-pitch, for example 1-1/4"-8. B7 bolts are listed as partial thread or full thread. Check the product title.
Finish
Finishes include plain, zinc and hot-dip galvanized steel. Stainless is passivated. Plain steel has no coating. Hot-dip galvanizing adds a thick zinc coating for outdoor and wet exposure. Use galvanized nuts and washers with galvanized bolts, and keep to one coating process: don't mix hot-dip and mechanically galvanized parts.
Length
Bolt length is measured from under the head to the end of the bolt. Stocked lengths run from 1-1/4" to 18" depending on diameter and grade.
Nuts and washers
Pair heavy hex bolts with heavy hex nuts. A heavy hex nut uses the same wrench size as the heavy hex bolt head on structural sizes. Add flat washers as the joint requires.
Bulk boxes
Heavy hex bolts are sold by the Bulk Box. Bulk box counts depend on size. Need volume pricing? See wholesale.
