M3 × 0.5
- Supplier starting drill
- 2.5 mm
- Conditional drill estimate
- 2.545 mm
- Series
- Coarse
More dimensions
- D − pitch estimate
- 2.5 mm
VALICALC · TECHNICAL REFERENCE
Metric Tap Drill Chart
Find a starting drill for a selected metric cutting tap. Source recommendations and formula estimates are displayed separately so their assumptions remain clear.
QUICK LOOKUP
Search within the verified subset. Numeric sizes match complete designations; a nearby size is a candidate, not an exact match.
SELECTED REFERENCE
M8 × 1.25
- Supplier starting drill
- 6.8 mm
- Conditional drill estimate
- 6.863 mm
- Series
- Coarse
All fields & cell provenance
- D − pitch estimate
- 6.75 mm
- Cutting tap: Bolt Depot metric pitch product reference — Metric Thread Pitch Table: diameter 8 · verified 2026-10-06 · source value M8 × 1.25.
- Supplier starting drill: Accu ISO Metric Thread Dimensions — Metric product chart: tapping drill 8 · verified 2026-10-06 · source value 6.8.
- Conditional drill estimate: OSG Tap Drill Size chart — Cutting-tap equation, conditional full-thread percentage · verified 2026-10-06.
- Series: Bolt Depot metric pitch product reference — Metric Thread Pitch Table: diameter 8 · verified 2026-10-06 · source value Coarse.
- D − pitch estimate: OSG Tap Drill Size chart — Authored D-P starting estimate; not a recommendation · verified 2026-10-06.
v1.1.0 · verified 2026-10-06 · values use the valid conditions shown above
M8 × 1.256.8 mmBack to answer ↑
Explore the verified data
16 matching rows · 16 in this subset
| Cutting tap | Supplier starting drill | Conditional drill estimate | Series | Actions |
|---|---|---|---|---|
| M3 × 0.5 | 2.5 mm | 2.545 mm | Coarse | |
| M4 × 0.7 | 3.3 mm | 3.363 mm | Coarse | |
| M5 × 0.8 | 4.2 mm | 4.273 mm | Coarse | |
| M6 × 1 | 5 mm | 5.091 mm | Coarse | |
| M8 × 1 | 7 mm | 7.091 mm | Fine | |
| M8 × 1.25 | 6.8 mm | 6.863 mm | Coarse | |
| M10 × 1 | Not available | 9.091 mm | Fine | |
| M10 × 1.5 | 8.5 mm | 8.636 mm | Coarse | |
| M10 × 1.25 | Not available | 8.863 mm | Fine | |
| M12 × 1.5 | Not available | 10.636 mm | Fine | |
| M12 × 1.25 | Not available | 10.863 mm | Fine | |
| M12 × 1.75 | 10.2 mm | 10.409 mm | Coarse | |
| M14 × 1.5 | Not available | 12.636 mm | Fine | |
| M14 × 2 | 12 mm | 12.181 mm | Coarse | |
| M16 × 2 | 14 mm | 14.181 mm | Coarse | |
| M20 × 2.5 | 17.5 mm | 17.727 mm | Coarse |
M4 × 0.7
- Supplier starting drill
- 3.3 mm
- Conditional drill estimate
- 3.363 mm
- Series
- Coarse
More dimensions
- D − pitch estimate
- 3.3 mm
M5 × 0.8
- Supplier starting drill
- 4.2 mm
- Conditional drill estimate
- 4.273 mm
- Series
- Coarse
More dimensions
- D − pitch estimate
- 4.2 mm
M6 × 1
- Supplier starting drill
- 5 mm
- Conditional drill estimate
- 5.091 mm
- Series
- Coarse
More dimensions
- D − pitch estimate
- 5 mm
M8 × 1
- Supplier starting drill
- 7 mm
- Conditional drill estimate
- 7.091 mm
- Series
- Fine
More dimensions
- D − pitch estimate
- 7 mm
M8 × 1.25
- Supplier starting drill
- 6.8 mm
- Conditional drill estimate
- 6.863 mm
- Series
- Coarse
More dimensions
- D − pitch estimate
- 6.75 mm
M10 × 1
- Supplier starting drill
- Not available
- Conditional drill estimate
- 9.091 mm
- Series
- Fine
More dimensions
- D − pitch estimate
- 9 mm
M10 × 1.5
- Supplier starting drill
- 8.5 mm
- Conditional drill estimate
- 8.636 mm
- Series
- Coarse
More dimensions
- D − pitch estimate
- 8.5 mm
M10 × 1.25
- Supplier starting drill
- Not available
- Conditional drill estimate
- 8.863 mm
- Series
- Fine
More dimensions
- D − pitch estimate
- 8.75 mm
M12 × 1.5
- Supplier starting drill
- Not available
- Conditional drill estimate
- 10.636 mm
- Series
- Fine
More dimensions
- D − pitch estimate
- 10.5 mm
M12 × 1.25
- Supplier starting drill
- Not available
- Conditional drill estimate
- 10.863 mm
- Series
- Fine
More dimensions
- D − pitch estimate
- 10.75 mm
M12 × 1.75
- Supplier starting drill
- 10.2 mm
- Conditional drill estimate
- 10.409 mm
- Series
- Coarse
More dimensions
- D − pitch estimate
- 10.25 mm
M14 × 1.5
- Supplier starting drill
- Not available
- Conditional drill estimate
- 12.636 mm
- Series
- Fine
More dimensions
- D − pitch estimate
- 12.5 mm
M14 × 2
- Supplier starting drill
- 12 mm
- Conditional drill estimate
- 12.181 mm
- Series
- Coarse
More dimensions
- D − pitch estimate
- 12 mm
M16 × 2
- Supplier starting drill
- 14 mm
- Conditional drill estimate
- 14.181 mm
- Series
- Coarse
More dimensions
- D − pitch estimate
- 14 mm
M20 × 2.5
- Supplier starting drill
- 17.5 mm
- Conditional drill estimate
- 17.727 mm
- Series
- Coarse
More dimensions
- D − pitch estimate
- 17.5 mm
How to use this data
Approximate start:D-P. Conditional cutting estimate:D −0.01299×percentage×P. This calculation is separate from the supplier's stated starting drill.
- Cutting taps only. Full-thread percentage is an estimate, not a universal requirement.
- Stock drill selection, material and specified minor-diameter limits still need checking.
CHECK THE METHOD
Worked example
M8×1.25: supplier start 6.8 mm; D-P estimate 6.75 mm; the 70% equation gives 6.863375 mm.
Continue the reference workflow
Common lookup questions
Why do the drill values differ?
Supplier starts and percentage-based estimates use different assumptions. Neither substitutes for the tap maker's material and minor-diameter guidance.
TRACEABLE DATA
Sources, scope & verification
Dataset v1.1.0
Last verified:
Same 16 common metric thread variants; supplier cutting-drill facts available only where individually sourced.
Values are curated product facts or generated scenarios. Paid standards, complete catalogs and source diagrams are not reproduced. A verification date applies to this documented subset.
Bolt Depot metric pitch product reference ↗
Type C · BOLT · page version not stated
Selected dimensional product facts only; no catalog text, diagrams, standard tolerances or full paid-standard tables.
Full provenance & artifact record
- Source checked
- 2026-10-06
- Use basis
- bounded-product-facts
- Artifact SHA-256
- Public web page inspected; no retained source artifact hash.
Accu ISO Metric Thread Dimensions ↗
Type C · ACCU · page version not stated
Selected dimensional product facts only; no catalog text, diagrams, standard tolerances or full paid-standard tables.
Full provenance & artifact record
- Source checked
- 2026-10-06
- Use basis
- bounded-product-facts
- Artifact SHA-256
- Public web page inspected; no retained source artifact hash.
Accu YG-1 M8×1 TD844376 cutting-tap product ↗
Type C · ACCU · Product TD844376, public specification
Selected dimensional product facts only; no catalog text, diagrams, standard tolerances or full paid-standard tables.
Full provenance & artifact record
- Source checked
- 2026-10-06
- Use basis
- bounded-product-facts
- Artifact SHA-256
- Public web page inspected; no retained source artifact hash.
OSG Tap Drill Size chart ↗
Type A · OSG · 800274CA-V3 / 2024
Original equations and generated scenario values; no copied reference table.
Full provenance & artifact record
- Source checked
- 2026-10-06
- Use basis
- authored-formula
- Artifact SHA-256
- 20cf70a1a4b075ed05a818f08b16f1bed2161219258d8752e41d149489f05a51