ASME B1.1 UNF Thread Limiting Dimensions — External 2A / Internal 2B (#0 – 1 1/2 in)

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 (ASME B1.1 UNF Thread Limiting Dimensions — External 2A / Internal 2B (#0 – 1 1/2 in)) 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.

Fine (UNF) threads carry similar tolerances to coarse — so what actually changes when a drawing moves from UNC to UNF?

What changes is where the metal is and what assembly must deliver. The collected charts show it directly: at 1/2 in, UNF runs 20 TPI against UNC's 13, so the fine thread's minor diameter max is 0.4392 in versus roughly 0.4069 for the coarse — a larger core, which is why a fine-thread bolt of the same grade carries more tensile load and why fatigue-critical and vibration-exposed joints specify fine. Per turn, the nut advances less (finer clamp adjustment), and the shallower helix resists backing off. Against those gains, three operational costs. First, engagement length: the fine thread needs a longer engaged length to develop the same stripping strength, so thin tapped walls or short bosses may be forced back to coarse. Second, handling: shallower flanks bruise more easily — a dropped fine-thread part that a coarse one would shrug off can be ruined, and dirty or paint-bridged holes assemble harder. Third, gaging discipline: the tolerance bands gage at higher TPI, so worn NOGO rings and skip-dirty plug gauges mislead more readily — keep gage calibration tighter on fine work. The limits on this page give both faces of the 2A/2B pair for checking any of it; 3A/3B or UNEF stays per RFQ.

What is the MOQ and lead time for threaded parts on this standard?

The minimum order quantity is 10,000 pieces. Stock items ship in 3–7 days; non-stock items are confirmed at quotation. Common thread sizes on this standard are widely stocked; confirm the exact schedule against quantity and size mix at quotation.