Threaded Insert Drilling Depth (Metric Threads)
Per-thread drilling data for threaded insert installations in metric sizes M2 through M45 — tap drill diameter, drilled-hole diameter limits, tap minimum outer diameter, and the drilling depth the hole needs for insert engagements from 0.5d to 3d.
Specifications
A threaded insert is only as good as the hole you drill for it, and on a blind hole the depth error shows up as either a coil floating above the floor or a tap that bottoms out before the thread is complete. This chart gives the machining numbers for metric threads from M2 to M45: for each designation (coarse pitch plus the fine-pitch variants the source tabulates, e.g. M8, M8x1; M12, M12x1 / M12x1.25 / M12x1.5), the drill bit diameter for the pre-tap hole, the minimum and maximum drilled diameter the tap can accept, the tap minimum outer diameter, and the drilling depth required for insert engagements of 0.5d, 0.75d, 1d, 1.5d, 2d, 2.5d and 3d, where d is the nominal thread diameter. The engagement columns are the design input: pick how deep the insert must sit (commonly 1d to 1.5d for standard installations, deeper for soft parent material or high pull-out loads), then take the drilling depth straight from that column instead of computing tap approach by hand. Three cells in the source's largest rows carry obvious print defects — M36x1.5 at 2d (49.3), M36 at 0.75d (13.8) and M42 at 2.5d (9935) — and are carried here verbatim with flags rather than silently corrected; read those three cells against their row neighbours. Parent-material drilling factors, insert material and length selection are not tabulated here and are quoted per RFQ.
| Coverage | 57 metric thread rows, M2 through M45 — coarse pitches plus the fine-pitch variants the source tabulates (M8x1, M10x1, M10x1.25, M12x1/1.25/1.5, M14x1.25/1.5, M16x1.5, M18x1.5/2, M20x1.5/2, M22x1.5/2, M24x1.5/2, M26x1.5, M27x1.5/2, M28x1.5, M30x1.5/2, M33x2, M34x1.5, M36x1.5/2/3, M39x3, M42x3, M45x3) |
|---|---|
| Columns | Pitch (mm); drill bit diameter; drilling diameter min./max.; tap minimum outer diameter; drilling depth at 0.5d / 0.75d / 1d / 1.5d / 2d / 2.5d / 3d engagement — all mm as printed |
| Reading the depth columns | d = nominal thread diameter; the column value is the drilled depth the engagement needs, including tap approach — take it directly, do not re-derive |
| Verbatim defects (flagged, not normalized) | M36x1.5 2d prints 49.3; M36 0.75d prints 13.8; M42 2.5d prints 9935 — read against row neighbours |
| Not tabulated | Parent material drill-speed correction, insert length selection, insert material/coating — per RFQ |
| Nominal Diameter | Pitch (mm) | Drill Bit Diameter (mm) | Drilling Diameter | Tap | Minimum Drilling Depth | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| min. | max. | Min Outer Diameter | 0.5d | 0.75d | 1d | 1.5d | 2d | 2.5d | 3d | |||
| M2 | 0.4 | 2.1 | 2.09 | 2.18 | 2.52 | – | – | 3.6 | 4.6 | 5.6 | 6.6 | 7.6 |
| M2.5 | 0.45 | 2.6 | 2.60 | 2.70 | 3.08 | – | – | 5.1 | 6.3 | 7.6 | 8.9 | 10.1 |
| M3 | 0.5 | 3.2 | 3.11 | 3.22 | 3.65 | – | – | 5.8 | 7.3 | 8.8 | 10.3 | 11.8 |
| M3.5 | 0.6 | 3.7 | 3.63 | 3.76 | 4.28 | – | – | 6.9 | 8.6 | 10.4 | 12.2 | 13.9 |
| M4 | 0.7 | 4.2 | 4.15 | 4.29 | 4.91 | – | – | 7.8 | 9.8 | 11.8 | 13.8 | 15.8 |
| M5 | 0.8 | 5.2 | 5.17 | 5.33 | 6.04 | – | – | 9.2 | 11.7 | 14.2 | 16.7 | 19.2 |
| M6 | 1.0 | 6.3 | 6.22 | 6.41 | 7.30 | – | – | 11.2 | 14.2 | 17.2 | 20.2 | 23.2 |
| M7 | 1.0 | 7.3 | 7.22 | 7.41 | 8.30 | – | – | 12.1 | 15.6 | 19.1 | 22.6 | 26.1 |
| M8x1 | 1.0 | 8.3 | 8.22 | 8.41 | 9.30 | – | – | 13.0 | 17.0 | 21.0 | 25.0 | 29.0 |
| M8 | 1.25 | 8.4 | 8.27 | 8.48 | 9.62 | – | – | 14.2 | 18.2 | 22.2 | 26.2 | 30.2 |
| M9 | 1.25 | 9.4 | 9.27 | 9.48 | 10.62 | – | – | 15.2 | 19.7 | 24.2 | 28.7 | 33.2 |
| M10x1 | 1.0 | 10.25 | 10.22 | 10.41 | 11.30 | – | – | 15.0 | 20.0 | 25.0 | 30.0 | 35.0 |
| M10x1.25 | 1.25 | 10.4 | 10.27 | 10.48 | 11.62 | – | – | 16.2 | 21.2 | 26.2 | 31.2 | 36.2 |
| M10 | 1.5 | 10.5 | 10.32 | 10.56 | 11.95 | – | – | 17.3 | 22.3 | 27.3 | 32.3 | 37.3 |
| M11 | 1.5 | 11.5 | 11.32 | 11.56 | 12.95 | – | – | 18.3 | 23.8 | 29.3 | 34.8 | 40.3 |
| M12x1 | 1.0 | 12.3 | 12.22 | 12.41 | 13.30 | – | – | 17.2 | 23.2 | 29.2 | 35.2 | 41.2 |
| M12x1.25 | 1.25 | 12.4 | 12.27 | 12.48 | 13.62 | – | – | 18.2 | 24.2 | 30.2 | 36.2 | 42.2 |
| M12x1.5 | 1.5 | 12.5 | 12.32 | 12.56 | 13.95 | – | – | 19.3 | 25.3 | 31.3 | 37.3 | 43.3 |
| M12 | 1.75 | 12.5 | 12.38 | 12.64 | 14.27 | – | – | 20.3 | 26.3 | 32.3 | 38.3 | 44.3 |
| M14x1.25 | 1.25 | 14.4 | 14.27 | 14.48 | 15.62 | 13.2 | 16.7 | 20.2 | 27.2 | 34.2 | 41.2 | 48.2 |
| M14x1.5 | 1.5 | 14.5 | 14.32 | 14.56 | 15.95 | – | 17.7 | 21.3 | 28.3 | 35.3 | 42.3 | 49.3 |
| M14 | 2.0 | 14.5 | 14.43 | 14.73 | 16.60 | – | – | 23.3 | 30.3 | 37.3 | 44.3 | 51.3 |
| M16x1.5 | 1.5 | 16.5 | 16.32 | 16.56 | 17.95 | – | 19.3 | 23.3 | 31.3 | 39.3 | 47.3 | – |
| M16 | 2.0 | 16.5 | 16.43 | 16.73 | 18.60 | – | – | 25.3 | 33.3 | 41.3 | 49.3 | 57.3 |
| M18x1.5 | 1.5 | 18.5 | 18.32 | 18.56 | 19.95 | 16.3 | 20.8 | 25.3 | 34.3 | 43.3 | – | – |
| M18x2 | 2.0 | 18.5 | 18.43 | 18.73 | 20.60 | 18.3 | 22.8 | 27.3 | 36.3 | 45.3 | 54.3 | 62.0 |
| M18 | 2.5 | 18.75 | 18.54 | 18.90 | 21.25 | 20.2 | 24.7 | 29.2 | 38.2 | 47.2 | 56.2 | 64.0 |
| M20x1.5 | 1.5 | 20.5 | 20.32 | 20.56 | 21.95 | 17.3 | 22.3 | 27.3 | 37.3 | 47.3 | – | – |
| M20x2 | 2.0 | 20.5 | 20.43 | 20.73 | 22.60 | 19.3 | 24.3 | 29.3 | 39.3 | 49.3 | – | – |
| M20 | 2.5 | 20.75 | 20.54 | 20.90 | 23.25 | 21.2 | 26.2 | 31.2 | 41.2 | 51.2 | 61.2 | 71.2 |
| M22x1.5 | 1.5 | 22.5 | 22.32 | 22.56 | 23.95 | 18.3 | 23.8 | 29.3 | 40.3 | 51.3 | – | – |
| M22x2 | 2.0 | 22.5 | 22.43 | 22.73 | 24.60 | 20.3 | 25.8 | 31.3 | 42.3 | 53.3 | – | – |
| M22 | 2.5 | 22.75 | 22.54 | 22.90 | 25.25 | 22.2 | 27.7 | 33.2 | 44.2 | 55.2 | 66.2 | – |
| M24x1.5 | 1.5 | 24.5 | 24.32 | 24.56 | 25.95 | 19.3 | 25.3 | 31.3 | 43.3 | 55.3 | – | – |
| M24x2 | 2.0 | 24.5 | 24.43 | 24.73 | 26.60 | 21.3 | 27.3 | 33.3 | 45.3 | 57.3 | – | – |
| M24 | 3.0 | 24.75 | 24.65 | 25.05 | 27.90 | 25.1 | 31.1 | 37.1 | 49.1 | 61.1 | 73.1 | – |
| M26x1.5 | 1.5 | 26.5 | 26.32 | 26.56 | 27.95 | 20.3 | 26.8 | 33.3 | 46.3 | 59.3 | – | – |
| M27x1.5 | 1.5 | 27.5 | 27.32 | 27.56 | 28.95 | 20.8 | 27.6 | 34.3 | 47.8 | 61.3 | – | – |
| M27x2 | 2.0 | 27.5 | 27.43 | 27.73 | 29.60 | 22.8 | 29.6 | 36.3 | 49.8 | 63.3 | – | – |
| M27 | 3.0 | 27.75 | 27.65 | 28.05 | 30.90 | 26.6 | 33.4 | 40.1 | 53.6 | 67.1 | – | – |
| M28x1.5 | 1.5 | 28.5 | 28.32 | 28.56 | 29.95 | 21.3 | 28.3 | 35.3 | 49.3 | 63.3 | – | – |
| M30x1.5 | 1.5 | 30.5 | 30.22 | 30.56 | 31.95 | 22.3 | 29.8 | 37.3 | 52.3 | 67.3 | – | – |
| M30x2 | 2.0 | 30.5 | 30.43 | 30.73 | 32.60 | 24.3 | 31.8 | 39.3 | 54.3 | 69.3 | – | – |
| M30 | 3.5 | 31.0 | 30.76 | 31.21 | 34.55 | 30.3 | 37.8 | 45.3 | 60.3 | 75.3 | – | – |
| M33x2 | 2.0 | 33.5 | 33.43 | 33.73 | 35.60 | 25.8 | 34.1 | 42.3 | 58.8 | 75.3 | – | – |
| M33 | 3.5 | 34.0 | 33.76 | 34.21 | 37.55 | 31.7 | 40.0 | 48.2 | 64.7 | 81.2 | – | – |
| M34x1.5 | 1.5 | 34.5 | 34.32 | 34.56 | 35.95 | 24.3 | 32.8 | 41.3 | 58.3 | 75.3 | – | – |
| M36x1.5 | 1.5 | 36.5 | 36.32 | 36.56 | 37.95 | 25.3 | 34.3 | 43.3 | 61.3 | 49.3 | – | – |
| M36x2 | 2.0 | 36.5 | 36.43 | 36.73 | 38.60 | 27.3 | 36.6 | 45.3 | 63.3 | 81.3 | – | – |
| M36x3 | 3.0 | 37.0 | 36.65 | 37.05 | 39.90 | 31.1 | 40.1 | 49.1 | 67.1 | 85.1 | – | – |
| M36 | 4.0 | 37.0 | 36.87 | 37.34 | 41.20 | 34.8 | 13.8 | 52.8 | 70.8 | 88.8 | – | – |
| M39x3 | 3.0 | 40.0 | 39.65 | 40.05 | 42.90 | 32.6 | 42.4 | 52.1 | 71.6 | 91.1 | – | – |
| M39 | 4.0 | 40.0 | 39.87 | 40.34 | 44.20 | – | 46.1 | 55.8 | 75.3 | 94.8 | – | – |
| M42x3 | 3.0 | 43.0 | 42.65 | 43.05 | 45.90 | 34.1 | 44.6 | 55.1 | 76.1 | 97.1 | – | – |
| M42 | 4.5 | 43.0 | 42.98 | 43.50 | 47.85 | – | 46.0 | 57.5 | 78.5 | 9935 | – | – |
| M45x3 | 3.0 | 46.0 | 45.65 | 46.05 | 48.90 | 35.6 | 46.9 | 58.1 | 80.6 | 103.1 | – | – |
| M45 | 4.5 | 46.0 | 45.98 | 46.50 | 50.85 | – | 49.3 | 60.5 | 83.0 | 105.5 | – | – |
- Row 49 (M36x1.5): M36x1.5 2d cell prints "49.3" on the collected page — breaks the row own depth ladder (43.3 to 61.3); carried verbatim, not normalized.
- Row 52 (M36): M36 0.75d cell prints "13.8" on the collected page — out of ladder with its neighbours (34.8 / 52.8) and against the M36x1.5 row (34.3); carried verbatim, not normalized.
- Row 56 (M42): M42 2.5d cell prints "9935" on the collected page — carried verbatim, not normalized.
Materials
- The chart is material-independent — it sizes the hole; the insert is the material decision. State the parent material (aluminum, cast iron, steel, plastic) with the thread callout on the RFQ, because parent material sets both the engagement depth you choose from the d-columns and the insert series (wire, self-tapping, heat-set) we quote. Inserts are supplied in carbon steel, stainless (A2/A4) and exotic alloys per the family pages
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 (Threaded Insert Drilling Depth (Metric 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 quantities and lead times for this family are confirmed at quotation — send your sizes, grades and quantities on the RFQ and the quote will carry a firm schedule. Sample availability is confirmed with the 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 deep should I drill for a 1d insert engagement, and is 1d enough?
Read the 1d column at your thread row — that value already includes the tap approach the machining needs, which is why it is bigger than the nominal d. Whether 1d is enough is a joint decision, not a chart decision: 1d is the common choice in steel for standard load levels, 1.5d to 2d in aluminum and other soft parents where pull-out strength scales with engagement, and deeper where the load case is dynamic. The chart's job is to make whatever engagement you choose manufacturable: take the engagement column at your size, add your bottom-clearance margin, and the drilled depth is set. Watch the three flagged cells (M36x1.5 2d, M36 0.75d, M42 2.5d) — the source prints defective values there, so interpolate from the adjacent columns and confirm on the drawing before cutting metal.
Why are there several rows for the same nominal size, and which one applies?
Because pitch changes the tap and therefore the numbers. M12 appears as M12 (coarse, 1.75), M12x1.5, M12x1.25 and M12x1 — each fine pitch needs a smaller pre-tap drill and produces slightly different depth values, and a fine-pitch insert installed on coarse-pitch machining data runs a drilled hole at the wrong diameter limits. Match the row to the pitch printed on your drawing callout (M12x1.5 means fine pitch 1.5), not to the nominal size alone. If the drawing carries a pitch the chart does not tabulate, quote it per RFQ with the callout — the insert series is supplied across the family pages, and the machining data for untabulated pitches comes from the insert manufacturer's installation data for that series.
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