Can button head cap screws handle the same load as socket head cap screws?

No. Button head cap screws have a smaller hex drive recess relative to the thread size, which limits the maximum tightening torque. They are generally not recommended for high-torque or high-tension applications where socket head cap screws are preferred. Always check the manufacturer torque specifications.

Metric Button Head Cap Screw Calculator – M3 to M24 | CalcEngines

Mechanical Fastening Tools · CalcEngines

Button Head Cap Screw Calculator

Full ISO 7380 / DIN 7380 dimensions — head size, hex key, tap drill, counterbore, clearance holes, and thread engagement for M3 to M24.

ISO 7380 / DIN 7380 M3 – M24 mm / inch toggle vs SHCS compare 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

⚠ Drive strength note: Button head cap screws have a shallower hex recess than socket head screws. Do not exceed the manufacturer’s recommended tightening torque — over-torquing will strip the drive.

Button Head vs Socket Head (same thread size)

When to use button head: Low-profile surfaces, decorative/aesthetic applications, larger bearing surface on soft materials. Avoid in high-torque, high-vibration, or structural load-bearing joints.

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 7380 coarse pitch)

Size	Pitch	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 difference between a button head and socket head cap screw? +

Button head screws have a wider, lower dome-shaped head — larger head diameter but smaller head height than a socket head of the same thread size. They also use a smaller hex key. This makes them ideal for low-profile applications but unsuitable for high-torque joints due to the smaller drive recess.

What hex key does an M6 button head cap screw use? +

An M6 button head cap screw (ISO 7380) requires a 4 mm hex key. This is one size smaller than the 5 mm key needed for an M6 socket head cap screw. This is important to remember — using the wrong key can round out the drive.

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

An M8 button head has a head diameter of 14 mm. With a 0.30 mm machining margin the counterbore diameter is 14.3 mm. Counterbore depth is the head height (4.6 mm) plus 0.5 mm clearance = 5.1 mm. This is notably shallower than an M8 socket head counterbore (8.5 mm), which is the main advantage in thin panels.

What standard covers metric button head cap screws? +

Metric button head cap screws are standardised under ISO 7380-1 (plain) and ISO 7380-2 (with flange). The equivalent German standard is DIN 7380. These define all key dimensions for M3 through M24.

Can I use a button head screw instead of a socket head cap screw? +

Only in non-critical, low-torque applications. Button heads have a lower tightening torque rating than socket head cap screws of the same size because of the smaller hex drive. For structural, high-vibration, or precision clamping applications, socket head cap screws are the correct choice.