#0000 / #000 / #00 Miniature Machine Screw Threads
Unified miniature machine screw threads for #0000, #000 and #00 — external and internal thread limits at 160/120/90/96 TPI (NS class 2), with the collected tables: major, pitch and minor diameter limits and tolerances.
Last updated: 2026-11
Specifications
Below #0 the unified thread system leaves the numbered series and enters the miniature screw thread series: #0000 at 160 threads per inch (a 0.0210 in maximum major diameter — about half a millimetre), #000 at 120 TPI (0.0340 max major), and #00 at 90 or 96 TPI depending on the series called out (both a 0.0470 max major, differing in pitch diameter limits). These are the threads of instruments, optics, watch-level electronics and fine mechanism work, where the thread itself is often the largest feature on the part. The collected tables give both thread halves at class 2, NS series. The external table carries per thread: major diameter allowance and max/min (0000-160: 0.0210/0.0195), pitch diameter max/min with tolerance (0.0169/0.0158, tol. 0.0011) and a minor diameter value (0.0128 — the source prints a single value where its header implies a pair; see the table footnote). The internal table carries pitch diameter min/max with tolerance (0.0169/0.0181, tol. 0.0012) and major diameter minimum (0.0210); the internal minor diameter prints "---" in the source — not tabulated for these sizes. Two cautions belong on this page. First, the external allowance column prints 0.0000 throughout in the source, so the table does not show a separate allowance figure for these threads. Second, matching is unforgiving: #00 exists in both 90 and 96 TPI with different pitch limits, and a 90-TPI screw in a 96-TPI tapped hole will bind or strip — confirm the TPI from the drawing, not from the screw gauge alone. Materials and finishes are not tabulated — per RFQ.
| Thread series | Unified miniature screw threads, NS series, class 2: 0000-160, 000-120, 00-90 and 00-96 (both #00 pitches tabulated; pitch limits differ) |
|---|---|
| External limits | Major max/min: 0.0210/0.0195 (0000-160), 0.0340/0.0325 (000-120), 0.0470/0.0450 (both #00); pitch max/min/tol.: 0.0169/0.0158/0.0011 (0000-160) → 0.0402/0.0386/0.0016 (00-96); minor value 0.0128 → 0.0334 |
| Internal limits | Pitch min/max/tol.: 0.0169/0.0181/0.0012 (0000-160) → 0.0402/0.0418/0.0016 (00-96); major min: 0.0210 (0000-160) → 0.0470 (#00); internal minor not tabulated by the source ("---") |
| Selection caution | #00 exists at 90 and 96 TPI with different pitch diameter limits — a 90-TPI screw will not mate correctly with a 96-TPI tapped hole; confirm TPI from the drawing |
| Materials / finishes | Not tabulated by the collected specification — per RFQ (state material and finish at quotation) |
| Nominal Size and Threads per Inch | Series | Class | Major Dia. Allowance | Major Max | Major Min | Pitch Dia. Max | Pitch Dia. Min | Pitch Tol. | Minor Dia.* |
|---|---|---|---|---|---|---|---|---|---|
| 0000-160 | NS | 2 | 0.0000 | 0.0210 | 0.0195 | 0.0169 | 0.0158 | 0.0011 | 0.0128 |
| 000-120 | NS | 2 | 0.0000 | 0.0340 | 0.0325 | 0.0286 | 0.0272 | 0.0014 | 0.0232 |
| 00-90 | NS | 2 | 0.0000 | 0.0470 | 0.0450 | 0.0398 | 0.0382 | 0.0016 | 0.0326 |
| 00-96 | NS | 2 | 0.0000 | 0.0470 | 0.0450 | 0.0402 | 0.0386 | 0.0016 | 0.0334 |
- Row 1 (0000-160): The source prints "0.0000" in the major-diameter allowance column for every row — reproduced verbatim; the allowance prints as zero rather than a negative figure. The minor diameter prints a single value (marked *) where the source header implies a max/min pair — treat it as the minor envelope and verify against ASME B1.1 for critical design.
| Nominal Size and Threads per Inch | Series | Class | Minor Dia. Min* | Minor Dia. Max* | Pitch Dia. Min | Pitch Dia. Max | Pitch Tol. | Major Dia. Min |
|---|---|---|---|---|---|---|---|---|
| 0000-160 | NS | 2 | --- | --- | 0.0169 | 0.0181 | 0.0012 | 0.0210 |
| 000-120 | NS | 2 | --- | --- | 0.0286 | 0.0300 | 0.0014 | 0.0340 |
| 00-90 | NS | 2 | --- | --- | 0.0398 | 0.0414 | 0.0016 | 0.0470 |
| 00-96 | NS | 2 | --- | --- | 0.0402 | 0.0418 | 0.0016 | 0.0470 |
- Row 1 (0000-160): The internal minor-diameter cells print "---" for every row in the source — reproduced verbatim; the source does not tabulate the internal minor limits for these sizes.
Materials
- Material and finish specified per RFQ — miniature screws are commonly stainless or brass in instrument work; state the material and any plating with the order
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 (#0000 / #000 / #00 Miniature Machine Screw Threads) 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
Why do #00 threads come in two pitches, and how do I avoid mixing them?
The 90 and 96 TPI variants of #00 are parallel series that both exist in supply, and the collected tables show exactly how they differ: same major diameter envelope (0.0470/0.0450 external on both), different pitch diameter limits — external pitch max/min 0.0398/0.0382 at 90 TPI versus 0.0402/0.0386 at 96 TPI, and internal pitch 0.0398/0.0414 versus 0.0402/0.0418. The numbers are close enough that a screw gauge reads both as #00, which is how the mixing happens: a 90-TPI screw driven into a 96-TPI tapped hole engages only partially, binds after a turn or two, and strips the fine aluminium or brass thread it was meant to hold — at these sizes there is no recovery. The discipline is procedural, not dimensional: treat the two pitches as different fasteners in stores (label by TPI, not just by gauge size), and confirm the tapped drawing before ordering either half of the pair. The same care applies across the whole miniature series: thread wall thickness at 160 TPI is 0.00625 in per flank, so these threads carry alignment and light clamping loads, not structural ones — thread engagement of 2–3 diameters is the usual rule, and any load-bearing application should be an explicit RFQ line rather than an assumption from the table.
What is the MOQ and lead time for this item?
The minimum order quantity is 10,000 pieces. Stock items ship in 3–7 days; non-stock items are confirmed at quotation. Confirm the exact schedule against quantity and size mix at quotation.
Related knowledge
- Thread-Forming vs Thread-Cutting vs Thread-Rolling Self-Tapping Screws: What the Evidence Settles on Base Material
- Screw Family Selection by Base Material: Wood, Machine and Self-Tapping Threads, Engagement and Coating
- Hex Bolts vs Socket Head Cap Screws: What the Evidence Settles on Strength, Clearance and Cost
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