Established 2000 0161 304 7800
sales@bridge-engineering.net Trade counter · Stalybridge
BRIDGE ENGINEERING SERVICES LTD INDUSTRIAL PROCUREMENT & ENGINEERING SUPPLIES TRADING SINCE 2000
Call
Workshop & Production Tooling

Drilling, Tapping & Cutting Tools

General-purpose and high-performance tooling for maintenance, fabrication, machine shops and production environments—supported by practical product identification and sourcing.

Start Cutting Tool Finder Tap Drill Chart
Free engineering resources

Cutting Tools Technical Centre

Practical calculators, conversion charts and selection guides to help define an enquiry before Bridge Engineering verifies and quotes the tooling.

Send a Tool Enquiry
01

Cutting Tool Finder

Build a quote-ready recommendation for drilling, tapping, reaming or milling.

Open Tool →
02

Drilling Speed & Feed

Calculate spindle RPM and linear feed from manufacturer-supplied cutting data.

Open Tool →
03

Tapping RPM

Calculate spindle speed and synchronous feed for metric or imperial single-start threads.

Open Tool →
04

Pitch & TPI Converter

Convert metric pitch to threads per inch, or TPI back to millimetres.

Open Tool →
05

Drill Size Conversion

Search fractional, number, letter and metric drill-size equivalents.

Open Tool →
06

Tap Drill Size Chart

Search metric, unified and common British cutting-tap starting sizes.

Open Tool →
07

Tap Selection Guides

Compare spiral-point, spiral-flute, cutting and thread-forming taps.

Open Tool →
Complete cutting-tool supply

Tools for Hole-Making, Threading and Metal Cutting

Bridge Engineering can source standard catalogue tools, replacement references and application-specific tooling. Send the tool reference, required diameter and thread, workpiece material, machine type and whether the operation is through-hole or blind-hole.

01

Drilling

Jobber, stub, long-series, taper-shank, step, centre, spotting, masonry and specialist drill bits.

View dedicated range →
02

Tapping & Threading

Machine and hand taps, spiral-point and spiral-flute taps, thread-forming taps, dies and thread repair.

View dedicated range →
03

Milling & Cutting

End mills, slot drills, indexable milling tools, hole saws, annular cutters and saw blades.

View dedicated range →
04

Finishing & Preparation

Reamers, countersinks, counterbores, deburring tools, rotary burrs and toolholding accessories.

View dedicated range →
Workshop reference

Tap Drill Size Chart

Search common metric coarse, metric fine, UNC and UNF cutting-tap drill sizes. Select a row to prepare a quotation enquiry for the matching tap and drill.

Metric coarse tap drill reference
ThreadPitchRecommended drillConversionEnquire
M1 × 0.25 0.25 mm 0.75 mm 0.0295 in
M1.2 × 0.25 0.25 mm 0.95 mm 0.0374 in
M1.4 × 0.30 0.30 mm 1.10 mm 0.0433 in
M1.6 × 0.35 0.35 mm 1.25 mm 0.0492 in
M2 × 0.40 0.40 mm 1.60 mm 0.0630 in
M2.5 × 0.45 0.45 mm 2.05 mm 0.0807 in
M3 × 0.50 0.50 mm 2.50 mm 0.0984 in
M3.5 × 0.60 0.60 mm 2.90 mm 0.1142 in
M4 × 0.70 0.70 mm 3.30 mm 0.1299 in
M4.5 × 0.75 0.75 mm 3.70 mm 0.1457 in
M5 × 0.80 0.80 mm 4.20 mm 0.1654 in
M6 × 1.00 1.00 mm 5.00 mm 0.1969 in
M7 × 1.00 1.00 mm 6.00 mm 0.2362 in
M8 × 1.25 1.25 mm 6.80 mm 0.2677 in
M10 × 1.50 1.50 mm 8.50 mm 0.3346 in
M12 × 1.75 1.75 mm 10.20 mm 0.4016 in
M14 × 2.00 2.00 mm 12.00 mm 0.4724 in
M16 × 2.00 2.00 mm 14.00 mm 0.5512 in
M18 × 2.50 2.50 mm 15.50 mm 0.6102 in
M20 × 2.50 2.50 mm 17.50 mm 0.6890 in
M22 × 2.50 2.50 mm 19.50 mm 0.7677 in
M24 × 3.00 3.00 mm 21.00 mm 0.8268 in
M27 × 3.00 3.00 mm 24.00 mm 0.9449 in
M30 × 3.50 3.50 mm 26.50 mm 1.0433 in
M33 × 3.50 3.50 mm 29.50 mm 1.1614 in
M36 × 4.00 4.00 mm 32.00 mm 1.2598 in
M42 × 4.50 4.50 mm 37.50 mm 1.4764 in
M48 × 5.00 5.00 mm 43.00 mm 1.6929 in

Cutting taps vs forming taps

These values are for common cutting-tap applications. Thread-forming taps normally require a larger pre-hole and must use the tap manufacturer’s recommended drill size.

Material and engagement matter

The best drill size can change with workpiece material, tolerance, thread engagement and tool geometry. A slightly larger hole may improve tap life where the specification permits.

Verify before production

Confirm the current tap manufacturer’s data, required thread class and machine conditions before production or safety-critical work.

Reference basis: common nominal cutting-tap drill sizes. For application-specific selection, consult the current tap manufacturer’s technical data.

Help us select the right tool

Information to Include with Your Enquiry

  • Required diameter, thread and tolerance
  • Workpiece material and hardness where known
  • Through-hole or blind-hole operation
  • Machine type, spindle and toolholding
  • Current brand and tool reference
  • Required quantity or repeat usage
Tap drill questions

Common Tapping Questions

What tapping drill is commonly used for M8 × 1.25?

A 6.8 mm drill is a common starting size for an M8 × 1.25 cutting tap. Confirm the required thread engagement, material and current tap manufacturer’s recommendation before production.

What is the difference between metric coarse and metric fine?

Fine threads use a smaller pitch than the corresponding coarse thread diameter. They require a different tapping drill and are often selected for controlled adjustment, limited wall thickness or application-specific fastening requirements.

Can this chart be used for thread-forming taps?

No. Forming taps displace material rather than cutting it and normally require a larger pre-hole. Use the forming-tap manufacturer’s specified drill size for the material and required thread engagement.

What should I send when requesting a tap or cutting tool?

Include the diameter and pitch, workpiece material, through or blind hole, machine type, current tool reference and required quantity. A photograph of the tool and its markings can also help identification.

Need Taps, Drills or Cutting Tools?

Send us the size, material, application or existing reference for pricing and availability.