ANSI Hex Lag Screws — Thread, Head and Lead-Hole Tables

Documents

Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.

Quotation

• The fastener family (ANSI Hex Lag Screws — Thread, Head and Lead-Hole Tables) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
• Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
• Quantity per size and your target delivery date.
• Destination country, and any required documents (for example a mill test certificate) so the quote includes them.

Sample & supply

Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.

Storage & shipping

Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.

Why does the lead-hole diameter change so much with wood group?

Because a lag screw's holding power comes from the wood threads it forms, and those form only if the wood is pushed to its limit without being pushed past it. Hard Group I woods are dense and brittle in this mode: too small a pilot and the torque needed to drive builds until the screw's reduced root (see the D1 column — 0.371 at 1/2) twists off, the classic field failure. Soft Group III/IV woods are the opposite: an over-large pilot strips the fibers the screw needs to bear against, and withdrawal capacity drops sharply. The collected ladder encodes that split — at 1/2 in, 15/64 in soft against 11/32 in hard, a 40% spread on the same screw. The middle column (Group II) is where most general construction lumber sits. For structural connections the pilot is a specified dimension, not a field choice, and moisture content moves it — test on the actual timber.

Which numbers on these tables actually matter when ordering?

Three, in practice. Nominal size and thread length: the thread table's coarse pitches (down to 3-1/4 tpi at 1-1/8) are the withdrawal engine, and thread length is what engages the member — order by nominal size plus length with the thread length stated. Across-flats F for the wrench: the ladder runs one size over nominal (3/4-in wrench at 1/2, 1-7/8 at 1-1/4), which surprises nobody on site exactly once. And the lead-hole column pair for the wood group at install. The head/shoulder table matters for fixture design (the shoulder length S and fillet R set what seats against the surface), but it is geometry you get with the size, not an ordering variable. Coating and material are the other ordering decisions entirely — the tables are geometry, and the corrosion choice is made against the timber treatment, not against these columns.