What is the tap drill size for M6 socket head cap screw?

The tap drill for M6×1.0 thread is 5.0 mm (d minus pitch: 6.0 − 1.0 = 5.0 mm). This gives approximately 75% thread engagement, the standard for most materials.

What clearance hole should I use for an M10 socket head cap screw?

For M10, the ISO 273 clearance holes are: Close fit 10.5 mm, Normal fit 11.0 mm, Large fit 12.0 mm. Normal fit is recommended for most general engineering applications.

What is thread engagement length for metric screws?

Recommended minimum thread engagement is 1× diameter (1d) for steel into steel, 1.5× diameter (1.5d) for steel into aluminium, and 2× diameter (2d) for steel into cast iron or plastics.

Metric Socket Head Cap Screw Calculator – M1.6 to M24 | CalcEngines

Mechanical Fastening Tools · CalcEngines

Socket Head Cap Screw Calculator

Full ISO 4762 / DIN 912 dimensions — head size, hex key, tap drill, counterbore, clearance holes, and thread engagement for M1.6 to M24.

ISO 4762 / DIN 912 M1.6 – M24 mm / inch toggle Counterbore calc Free to use

Parameters

Nominal Size

Thread Pitch (mm) Coarse pitch shown first

Counterbore Margin (mm) Added to head Ø for pocketing

inch

Screw Dimensions

Select a size above and click Calculate.

Drilling & Fit

Recommended Thread Engagement Length

Thread engagement rule: Steel into steel ≥ 1×d · Steel into aluminium ≥ 1.5×d · Steel into cast iron / plastic ≥ 2×d

Full Reference Chart (ISO 4762 coarse pitch)

Size	Pitch (mm)	Head Ø dk	Head H k	Hex Key s	Tap Drill	Counterbore Ø	CB Depth	Clr Close	Clr Normal	Clr Large

Common Questions

What is the counterbore size for an M8 socket head cap screw? +

An M8 SHCS has a head diameter (dk) of 13 mm. With a standard 0.30 mm machining margin the counterbore diameter is 13.3 mm. Counterbore depth should be at least 8.5 mm (head height k + 0.5 mm clearance). Adjust the margin in the calculator above for your specific application.

What is the tap drill for an M6 socket head cap screw? +

The tap drill for M6×1.0 coarse thread is 5.0 mm (calculated as d − P = 6.0 − 1.0). This gives ~75% thread engagement, recommended for most engineering materials. For soft materials like aluminium or plastic, consider a 70% engagement drill slightly larger.

What is the difference between ISO 4762 and DIN 912? +

ISO 4762 is the international standard; DIN 912 is the German standard. They are dimensionally identical for all practical purposes — screws manufactured to DIN 912 will meet ISO 4762. Most modern metric SHCS sold globally are made to both standards simultaneously.

What clearance hole should I use for M10? +

For M10, ISO 273 defines three fits: Close 10.5 mm (precision alignment), Normal 11.0 mm (general engineering — recommended), and Large 12.0 mm (easy assembly where position tolerance is less critical).

How do I calculate minimum thread engagement length? +

As a rule of thumb: ≥ 1× diameter for steel into steel, ≥ 1.5× diameter for steel into aluminium, and ≥ 2× diameter for steel into cast iron or plastics. The calculator shows these values automatically for each selected screw size.