Heavy Hex Bolts

Heavy hex bolts are generally specified for high temperature or high pressure applications, particularly where bolt heads will bear against flanges. Standard diameters are 1/2″ and larger. The main difference between a heavy hex bolt and a regular (or finished) hex bolt is the distance across opposite flats of the hex. Heavy hex bolts are 1/8 of an inch larger than a finished hex bolt of the same diameter. The formula for determining hex size is one-and-a-half times the diameter plus 1/8″.
ASTM (ASME) A193 is one specification that is usually sited in connection with heavy hex bolts. Several different materials are covered by ASTM A193. Nickel Systems can supply bolting to A193 B8 (304 Stainless), A193 B8C (347 Stainless), A193 B8M (316 Stainless), A193 B8R (Nitronic® 50), A193 B8S (Nitronic® 60) and A193B8T (321 Stainless), as well as Strain Hardened ASTM A193 B8 Class 2 (304 Stainless) and A193 B8M Class 2 (316 Stainless).
Nickel Systems is not limited to materials covered by ASTM A193. Currently, we have heavy hex bolts in Hastelloy® C276 (Alloy C276) and Carpenter® 20 (Alloy 20) in stock. Bolting in other materials can be provided.

Several ASTM specifications require a hex head that is larger than a standard (finished) hex head. These specifications include: A193, A320 and A307B. Although A325 and A490 bolts also require a heavy hex head, please refer to Structural Bolts for dimensional specifications, since these bolts have shorter thread lengths than standard heavy hex bolts.

Applications

  • Heavy hex bolts can be used for many different applications that include fastening wood, steel, and other construction materials for projects such as docks, bridges, highway structures, and buildings. Heavy hex bolts with forged heads are also commonly used as headed anchor bolts.

Types

  • Cold Forged Fasteners, Hot Forged Fastener, C-Machined Heavy Hex Bolts, CNC Machined Heavy Hex Bolts, Custom Machined Heavy Hex Bolts, Threaded Heavy Hex Bolts, Non-Threaded Heavy Hex Bolts, Bar Stock Machined Heavy Hex Bolts.

Size Range

  • 5/16" - 6" according to ANSI / ASME
  • M8 - M150 according to ISO / DIN
  • Max Length 6000mm

Threads

  • Coarse, Fine, UNC, UNF, UN, BSW, Acme Threads with Half Thread, Full Thread & Double End Thread Configuration.

Services

Electro Zinc Plating Hot Dip Galvanizing Ptfe Fluorocarbon Coating
Aluminizing Ceramic Filled Fluorocarbon Coating Nickel Plating
Mechanical Zinc Coating Electro Zinc Colbalt Plating Electro Zinc Nickel Plating
Phosphate Coating Electro Less Nickel Plating Electro Cadmium Plating
Dacromet 320 500 Coating Pickled Passivated Fasteners Silver Plating
Zinc Plating Mechanical Galvanization ZN Phosphating
MN Phosphating Cadium Plating Zinco-Nickel Plating
Nickel Electroless Plating Burnishing Geomet
Customised Coating Ceramic Filled Fluorocarbon Coating  

Dimensional Standards

  • Materials - ASTM / ASME / BSI / ISO / Nace / AFNOR / DIN / AISI
  • Hexagonal Bolts - ANSI B18.2.1, ANSI B18.2.3.1M, DIN 931, DIN 933, BS 1768, UNI 5731, UNI 5737, UNI 5739, ISO 4014, ISO 4017, BS 1769, BS 3692
  • Socket/Slotted Set Screws - DIN 913, DIN 914, DIN 915, DIN 916, DIN 551, DIN 553, DIN 438, BS 4168
  • Socket/Slotted Countersunk Screws - DIN 963, DIN 7991, BS 4168, BS 1981, BS 483, BS 2470
  • Socket Cap Screws - ANSI B18.3, B18.3.1M, DIN 912, DIN 6912, DIN 7984, ANSI B18.3, ISO 4762, UNI 5931, BS 2470, BS 4168
  • Stud Bolts - ASME B18.2.1, DIN 976, DIN 938, DIN 939, DIN 2510, BS 4439, BS 2693, BS4882
  • Nuts - ANSI B18.2.2, ANSI B18.2.4.6M, DIN 934, DIN 936, BS 1768, BS 1769, BS 1083, BS 3692, ISO 4032, ISO 4033, ISO 4035, UNI 5587, UNI 5588, UNI 5589
  • Washers - ASME B18.22.1, ASTM F436, ISO 7089, DIN 125, DIN 9021, BS 4320, BS 3410, DIN 127, BS 4464, BS 1802, UNI 6952
  • Common Grades - SAE J429 Gr 5, SAE J429 Gr 8, ASTM A307 Gr A, ASTM A307 Gr B, ASTM A325 Type 1, ASTM A490 Type 1, ASTM A193 Gr B7, ASTM A193 Gr B7M, ASTM A193 Gr B16, ASTM A193 G B8, ASTM A320 Gr L7, ASTM A193 G B8M, BS 3692 Gr 4.8, BS 3692 8.8, BS 3692 Gr 10.9, BS 3692 12.9, JIS B1188 Class F8T, JIS B1185 Class F10T, SS304, SS316, SS316L, BS EN ISO 3506 A2-50, BS EN ISO 3506 A2-70, BS EN ISO 3506 A2-80, BS EN ISO 3506 A4-50, BS EN ISO 3506 A4-70, BS EN ISO 3506 A4-80

 

Bolt Diameter D F C H
Body Diameter Width Across Flats Width Across Corners Height
Max Basic Max Min Max Min Basic Max Min
1⁄2 0.515 7⁄8 0.875 0.850 1.010 0.969 11⁄32 0.364 0.302
5⁄8 0.642 11⁄16 1.062 1.031 1.227 1.175 27⁄64 0.444 0.378
3⁄4 0.768 11⁄4 1.250 1.212 1.443 1.383 1⁄2 0.524 0.455
7⁄8 0.895 17⁄16 1.438 1.394 1.660 1.589 37⁄64 0.604 0.531
1 1.022 15⁄8 1.625 1.575 1.876 1.796 43⁄64 0.700 0.591
11⁄8 1.149 113⁄16 1.812 1.756 2.093 2.002 3⁄4 0.780 0.658
11⁄4 1.277 2 2.00 1.938 2.309 2.209 27⁄32 0.876 0.749
13⁄8 1.404 23⁄16 2.188 2.119 2.526 2.416 29⁄32 0.940 0.810
11⁄2 1.531 23⁄8 2.375 2.300 2.742 2.622 1 1.036 0.902
15⁄8 1.658 29⁄16 2.562 2.481 2.959 2.829 13⁄32 1.116 0.978
13⁄4 1.785 23⁄4 2.750 2.662 3.175 3.035 15⁄32 1.196 1.054
17⁄8 1.912 215⁄16 2.938 2.844 3.392 3.242 11⁄4 1.276 1.130
2 2.039 31⁄8 3.125 3.025 3.608 3.449 111⁄32 1.388 1.175
21⁄4 2.305 31⁄2 3.500 3.388 4.041 3.862 11⁄2 1.548 1.327
21⁄2 2.559 37⁄8 3.875 3.750 4.474 4.275 121⁄32 1.708 1.479

Dimensions per ASME B18.2.1 2010