The tap drill for M4 x 0.7 is 3.3 mm (0.1299 in), which gives about 77% of full thread depth. The exact 75% hole is 0.1306 in (3.32 mm). The table lists every number, letter, fractional and metric drill that gives between 55% and 90% thread, so you can work from the bits you own.
| Drill | Type | in | mm | Thread | Note |
|---|---|---|---|---|---|
| 3.2 mm | metric | 0.1260 | 3.20 | 88% | deep, hard to tap |
| #30 | number | 0.1285 | 3.26 | 81% | deep, hard to tap |
| 3.3 mm | metric | 0.1299 | 3.30 | 77% | chart drill |
| 3.4 mm | metric | 0.1339 | 3.40 | 66% | easier to tap |
| #29 | number | 0.1360 | 3.45 | 60% | easier to tap |
About the M4 x 0.7 thread
M4 x 0.7 is the thread on many electronics and furniture fittings, small brackets, bicycle accessories and the smaller VESA monitor mounts (the 75 and 100 mm patterns on most monitors use M4 screws; large TVs use M6 or M8). It is also common in aluminium extrusion and jig hardware.
Diameter minus pitch gives 3.3 mm, the drill on almost every chart. It is often written as “4m x .7” or “M4 x .7”; the answer is the same. If your set has only 0.5 mm steps, 3.5 mm gives a much shallower thread (about 55%) that may strip in soft metal, so it is worth buying the 3.3 mm bit.
M4 x 0.7 thread dimensions
| Dimension | Value | Also |
|---|---|---|
| Nominal diameter | 4 mm | 0.1575 in |
| Pitch | 0.7 mm | 36.29 threads per inch equivalent |
| Basic pitch diameter | 3.545 mm | 0.1396 in |
| Basic minor diameter (nut) | 3.242 mm | 0.1276 in |
| Tensile stress area | 8.78 mm² | 0.0136 in² |
Clearance hole for M4
The tapped hole is in the part that holds the thread; the part being clamped gets a clearance hole the bolt passes through. For M4 a normal fit is 4.5 mm. Never drill the clearance part with the tap drill: the screw will not pass.
| Fit | Drill | Diameter |
|---|---|---|
| Close (ISO 273 fine) | 4.3 mm | 0.1693 in |
| Normal (ISO 273 medium) | 4.5 mm | 0.1772 in |
| Loose (ISO 273 coarse) | 4.8 mm | 0.1890 in |
How deep to drill a blind M4 x 0.7 hole
| Part material | Full thread wanted | Drill depth (full diameter) | Depth to drill tip (118°) |
|---|---|---|---|
| Steel or cast iron (1 × diameter) | 4.0 mm | 8.9 mm | 9.9 mm |
| Aluminium or brass (2 × diameter) | 8.0 mm | 12.9 mm | 13.9 mm |
Wrench size and torque for M4
- Hex bolt or nut: 7 mm wrench (ISO)
- Socket head cap screw (ISO 4762): 3 mm hex key
| Bolt grade | Dry | Lubricated |
|---|---|---|
| Class 8.8 | 3.1 N·m (2.3 ft-lb) | 2.3 N·m |
| Class 10.9 | 4.4 N·m (3.2 ft-lb) | 3.3 N·m |
| Class 12.9 | 5.1 N·m (3.8 ft-lb) | 3.8 N·m |
Threads easily mistaken for M4 x 0.7
| Thread | Diameter (in) | Diameter (mm) | Pitch |
|---|---|---|---|
| M4 x 0.7 (this page) | 0.1575 | 4.00 | 0.7 mm (36.3 TPI) |
| #8-32 UNC | 0.1640 | 4.17 | 32 TPI (0.79 mm) |
| #8-36 UNF | 0.1640 | 4.17 | 36 TPI (0.71 mm) |
Tips for tapping M4 x 0.7
- VESA mount screws: check the length as well as the thread; screws that bottom out in the TV can crack the panel housing.
- M4 and #8-32 are close in diameter (0.157 vs 0.164 in) but not interchangeable.
- In aluminium, aim for about 8 mm (2 x diameter) of full thread; in steel, 4 to 6 mm is enough.
- An M4 socket head cap screw takes a 3 mm hex key.
Frequently asked questions
What size drill bit for an M4 x 0.7 tap?
3.3 mm, which gives about 77% thread. The exact 75% size is 0.1306 in (3.32 mm).
How deep should a blind M4 x 0.7 hole be?
For a full thread of 1 × diameter in steel, drill about 8.9 mm at full diameter with a plug tap, or 9.9 mm to the drill tip; in aluminium, about 12.9 mm.
What size drill for M4 x 0.7 in inches?
#30 (0.1285 in, 3.26 mm) is the closest inch drill to 3.3 mm; 1/8 in (0.125 in) gives a deeper thread that is harder to tap.
What is the clearance hole for an M4 bolt?
4.3 mm close, 4.5 mm normal and 4.8 mm loose (ISO 273).
Sources and method
Every dimension and percentage on this page is computed from the formulas listed, not copied from another chart. Values are basic (nominal); real parts are made to tolerance classes (2A/2B for inch, 6g/6H for metric).
- ASME B1.1 and FED-STD-H28/2B (Unified inch), ISO 68-1 and ISO 261 (metric): basic thread profile and stress area formulas.
- Machinery’s Handbook (Industrial Press): percentage-of-thread relation used by our tap drill size calculator.
- ASME B94.11M twist drill series (number, letter, fractional); 0.1 mm metric drill steps.
- ISO 273 metric clearance holes; inch close, normal and loose fits as published in the ASME B18.2.8 clearance classes.
- SAE J429 and ISO 898-1 proof strengths; T = K × D × F torque relation (see our bolt torque chart for the full method).
- Wrench and hex key sizes: ASME B18.2.1, ASME B18.3, ASME B18.6.3, ISO 4014/4017, DIN 933 and ISO 4762 values as widely published.
More thread and fastener tools
- All thread and fastener charts
- UNC and UNF thread chart
- Metric thread pitch chart
- Tap drill chart (inch and metric)
- Clearance hole chart
- Nail size chart
- Wood screw size chart
- Lag screw pilot hole chart
- Bolt torque chart
- Wrench size chart
- Drill bit size chart
- Thread engagement chart
- Nail gun nail sizes by gauge
- Screw and nail size calculator
- Tap drill size calculator
- Clearance hole size calculator
- Tapped hole depth calculator
Last reviewed: 24 October 2026. How we build and check our data: methodology and corrections. Spotted an error? Please let us know.