What material grade does Lag Bolts use?

Lag Bolts are manufactured per the applicable ASTM, ASME, DIN, or ISO specification for the material grade. TorqBolt provides material test certificates (MTC) per EN 10204 3.1 or 3.2 with every supply.

What sizes are available for Lag Bolts?

TorqBolt manufactures Lag Bolts in metric sizes M6 to M100 and imperial sizes 1/4" to 4" diameter, with custom lengths from 10mm to 3000mm. Non-standard sizes are available on request.

Are Lag Bolts NACE MR0175 / ISO 15156 certified?

Yes, Lag Bolts can be supplied with NACE MR0175 / ISO 15156-2/3 sour service certification when specified at order. Material certificates and test reports are provided.

What is the typical delivery time for Lag Bolts?

Standard stock items ship in 1-2 weeks. Custom manufactured Lag Bolts typically ship in 4-6 weeks depending on quantity, material availability, and certification requirements.

Do you provide third-party inspection for Lag Bolts?

Yes, third-party inspection by TUV, Lloyd's Register, BV, DNV, SGS, and Intertek is available upon request for Lag Bolts. Witness testing and stage inspections can be arranged.

Lag Bolts Manufacturer & Supplier

Lag Bolts

Lag bolts are used to fasten wood to wood and metal to wood, attach objects to wood, and affix items to concrete and masonry when combined with lag expansion shields. They are heavy-duty wood screws that are available in larger sizes—both in terms of diameter and length—and usually have a hex head to facilitate higher installation torque using a wrench. While lateral strength is lower than a comparable bolt and nut, lag bolts are useful when access to one side of the joint is limited, the appearance of a nut is undesirable or through-bolt length is excessive. Lag bolts are also known as: hex lag bolts, lag screws, coach screws. Being a thread-forming-type screw, they create their own mating threads during installation—no nut is needed so a through-hole is not required.

TorqBolt manufactures LAG Bolts via cold forging, hot forging and CNC machining. Sizes range from M1.0 to M100 (metric) and 1/16" to 4" (imperial). Available in coarse, fine, UNC, UNF, UN, BSW and acme threads with half, full or double-end thread configurations. Each LAG Bolts batch is supplied with EN 10204 3.1 or 3.2 material test certificates.

Hexagon 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

Surface Treatments & Coatings

Electro Zinc Plating Hot Dip Galvanizing Ptfe Fluorocarbon Coating Aluminizing Ceramic Filled Fluorocarbon Coating Nickel Plating Mechanical Zinc Coating Electro Zinc Cobalt Plating Electro Zinc Nickel Plating Phosphate Coating Electro Less Nickel Plating Electro Cadmium Plating Dacromet 320 500 Coating Pickled Passivated Fasteners Silver Plating

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Lag Bolts — Specifications & Dimensions

Lag bolts are externally threaded fasteners with an integral head, manufactured per ASME B18.2.1, ISO 4014/4017, and DIN 933/931. TorqBolt produces Lag bolts in metric (M6–M100) and imperial (1/4"–4") diameters with custom lengths from 10 mm up to 3000 mm.

Head Styles Available

Hex head — ASME B18.2.1, the workhorse for general bolting

Heavy hex head — thicker head for high-load joints, ASTM A325 / A490 patterns

Socket head cap (SHCS) — ASME B18.3 / DIN 912, ideal where space is limited

Button head, flat head, countersunk — flush-mount applications

12-point flange — tool-engagement-critical assemblies

Thread & Shank

Lag bolts are supplied with full or partial threading. Full-thread (UNC, UNF, ISO metric coarse/fine) for tension-only joints; partial-thread shank for shear loads where the unthreaded grip carries the load. Thread fits per ASME B1.1 (Class 2A) or ISO 965 (6g) by default; tighter Class 3A / 4h6h fits available on request. Engagement length follows the 1.5×D rule for tapped holes; 1.0×D minimum on through-bolting.

Mechanical Performance

Lag bolts achieve characteristic tensile strength, yield, and elongation per the source-material spec, with proof-load testing and hardness verification per ASTM F606 / ISO 898-1. Torque-tension calibration is published per ASME PCC-1 for critical joints. Each lot ships with EN 10204 3.1 (or 3.2 on request) certificates listing chemistry, mechanicals, hardness, and dimensional inspection.

Custom Configurations

TorqBolt can produce Lag bolts to drawing, with non-standard heads, drilled-shank variants, double-end, captive, or matched-set configurations. Coatings include zinc, PTFE, Xylan, hot-dip galvanized, and electroless nickel. NACE MR0175 / ISO 15156 sour-service certification on request.

Specialty Fastener Alloys

TorqBolt manufactures specialty fasteners across the full range of corrosion-resistant alloys (CRAs), high-temperature superalloys, and engineered metallurgies required by the process industries. Beyond the high-volume Inconel, Hastelloy, Duplex, and stainless grades, our supply chain covers a long tail of specification-driven alloys for unique service envelopes — sour wells, extreme cryogenics, pharmaceutical-grade purity, oxidizing acids, chlorinated solvents, and high-temperature cyclic-load fasteners.

Each specialty alloy is sourced from approved mills with full melt traceability through a closed forging route. Heat-treat condition, mechanical properties, and corrosion testing are controlled to the customer's drawing or governing specification — whether ASTM, ASME, AMS, MIL, NORSOK, NACE, or proprietary end-user codes. EN 10204 3.1 (mill cert) or 3.2 (third-party witnessed) material test certificates are issued with every lot, listing chemistry, mechanicals at relevant test temperatures, hardness, dimensional inspection, and any corrosion or NDT test results required.

Third-party inspection by TUV, Lloyd's, BV, DNV, SGS, and Intertek is arrangeable. NACE MR0175 / ISO 15156 sour-service qualification, NORSOK M-650 mill qualification, API 6A wellhead bolting, API 20E subsea bolting, and PED 2014/68/EU pressure-equipment compliance available across the alloy range as the application demands.

Lag Bolts

Lag Bolts

Hexagon Bolts

Socket/Slotted Set Screws

Socket/Slotted Countersunk Screws

Socket Cap Screws

Stud Bolts

Nuts

Washers

Please contact our Sales Team for more information on Lag Bolts

Lag Bolts — Specifications & Dimensions

Head Styles Available

Thread & Shank

Mechanical Performance

Custom Configurations

Specialty Fastener Alloys