Standard T-Nuts (ASME B5.1M)
ASME B5.1M T-nut dimensions, nominal sizes M4 to M42 (with inch counterparts): width A3, stud tap E3, width B3, height C3, thickness K3, length L3, and corner rounds — the machine-tool table slot nut ladder.
Last updated: 2026-11
Specifications
T-nuts slide into machine-tool table slots and anchor by a stud threaded through the tapped bore, and the collected B5.1M tables lay out the full geometry across nominal sizes 4 to 42 mm with inch counterparts. Width A3 (the slot-engaging tongue) runs max/min in both units (0.330/8.7 at the 8 mm size — the inch column printed in decimals, the mm column in whole/tenths), tap for stud E3 pairs UNC-3B and ISO threads per size (0.250-20 / M6 at 8 mm up to 1.250-7 / M30 at 36), width B3 max/min (0.562/0.531 to 2.500/2.469 in), and the second table carries height C3 (0.188/0.172 at 8 mm up to 0.938/0.906 at 30), thickness K3 and length L3 (0.562/18 at 8 mm to 2.062/53 at 30). The ladder starts ragged: the 4 and 5 mm rows print "-" across the geometry columns (carried verbatim — the collected source tabulates them by nominal only), and the 42/48 mm rows carry mm-only values with "-" in the inch columns. Table 3 carries the corner rounds R3/W3. Metric T-slot hardware under DIN 508 / ISO 299 are the registered metric identities; this ASME dual-unit table is the inch-machine-tool identity.
| Standard / scope | ASME B5.1M standard T-nuts, nominal sizes 4-42 mm with inch counterparts — dual-unit geometry tables; the 4/5 mm rows print "-" (no tabulated geometry on the collected page) |
|---|---|
| Width A3 / stud tap E3 | A3 max/min: 0.330/8.7 (8 mm) to 1.523/39.25 (36 mm); E3 UNC-3B / ISO: 0.250-20 / M6 (8 mm), 0.500-13 / M12 (16), 0.750-10 / M20 (24), 1.250-7 / M30 (36) |
| Width B3 | Max/min: 0.562/0.531 (8 mm) to 2.500/2.469 (36); mm max/min 15/14 to 64/63 — 42/48 mm rows print mm-only (75/74, 85/84) with "-" in the inch columns |
| Height C3 / thickness K3 / length L3 | C3 max/min 0.188/0.172 (8 mm) to 0.938/0.906 (30); K3 0.281/9 (8) to 1.312/34 (30); L3 0.562/18 (8) to 2.062/53 (30) |
| Corner rounds | R3 and W3 per size (table 3) as printed |
| Not tabulated | Material/hardness, slot class match (the table slot the nut fits is specified by the machine tool builder), stud lengths — per RFQ |
Materials
- T-nuts are case-hardened low-carbon steel as a rule so the threads survive stud clamping while the tongue stays tough; stainless and black-oxide variants exist for corrosion service. The binding selection variable is the table-slot size match — order the nut by the machine tool's slot number/stud size, not by nominal thread alone, and confirm the slot class with the tool builder for heavy clamping
Ordering & documentation
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 (Standard T-Nuts (ASME B5.1M)) 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.
Frequently asked questions
How do I pick the right T-nut for a machine table slot?
From the slot, not the bolt. The controlling dimension is width A3 — the tongue that drops into the table slot — and the collected table shows it paired with the stud tap E3 per nominal size (8 mm nut: A3 0.330/8.7, tapping 1/4-20 UNC-3B or M6 ISO). Machine-tool table slots come in standardized sizes, so the selection order is: read the slot size off the table (or its manual), pick the nut nominal whose A3 max fits that slot, and take the stud thread the E3 column offers — the M-thread and UNC options in the same row exist exactly because inch-slot machines take inch-stud tooling and vice versa. Then check height C3 against your clamp stack and length L3 against slot pitch. Ordering by stud thread alone is the common mistake: a nut can be tapped M10 and still not fit your slot.
The 4/5 mm rows and the 42/48 mm rows print mostly "-" — what does that mean?
That the collected source does not tabulate geometry there, carried verbatim rather than reconstructed. At the small end, the 4 and 5 mm nominals print only the size row — no A3/E3/B3 values — so on this table the practical series starts at 8 mm; if a small-slot fixture genuinely needs a 4 or 5 mm T-nut, its geometry has to come from the tool builder or another standard, not from this ladder, and that is a per-RFQ item. At the large end the 42/48 mm rows carry mm values for B3 (75/74, 85/84) with the inch columns empty — a dual-unit table where the big sizes are metric-only territory. The evidence rule on this page is the usual one: "-" is the source saying "not tabulated here", not a zero, and any size whose geometry this page does not carry is quoted per RFQ.
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support