M52 Bolt & Screw Dimensions: Diameter & Head Size

Q: What clearance hole size is needed for an M52 screw or bolt?

For an M52 fastener, a 54.00mm drill bit is utilized for a Close Fit, a 56.00mm bit is used for a Normal Fit, and a 62.00mm bit is recommended for a Loose Fit. A Normal Fit is the industry standard to ensure the massive bolt shank passes through the assembly without binding while maintaining structural alignment.

Q: What is the difference between a bolt and a screw?

The difference is based on the intent of the fastener’s use; If the primary intent is for the fastener to pass through an unthreaded hole and be assembled with a nut, it is a Bolt. In this application, you usually hold the head and turn the nut to apply tension. But if the primary intent is for the fastener to be installed into a threaded (tapped) hole, it is a Screw. In this application, the connection is tightened by turning the head of the fastener itself.

M52 bolt or screw dimensions and sizes are heavy-duty fasteners critical for massive structural steel joints, heavy maritime engineering, large-scale industrial presses, and primary infrastructure anchoring. This size has a 52.00mm nominal major diameter and is available in M52 x 5.0 for the coarse series, where 5.0 represents the thread pitch in millimeters. This reference chart follows respective DIN and ISO standards for each head style and DIN 13-1 (coarse) and ISO 68-1 standards for thread dimensions to ensure global compatibility.

Disclaimer: Actual dimensions and tolerances may vary slightly depending on head style (e.g., Heavy Hex, Stud Bolts, Anchor Bolts), manufacturer, or material grade — always verify with the official product datasheet before use.

Thread diagram for bolt and screw depicting the major diameter, minor diameter, pitch diameter, and thread pitch

M52 x 5.0 Screw & Bolt – DIN 13-1/ISO 68-1
Dimension	Size (mm)
Dimension	Min	Max
Major Diameter	51.399	51.929
Pitch Diameter	48.445	48.681
Minor Diameter	45.365	46.516
Thread Pitch	5.0
Major Diameter	51.399	51.929
Pitch Diameter	48.531	48.681
Minor Diameter	45.451	46.516
Thread Pitch	5.0

Major Diameter – The largest diameter of the external thread, measured crest to crest. This defines the nominal size (e.g., M12 which is 12 mm of nominal major diameter).
Pitch Diameter – The diameter of an imaginary cylinder where the thread thickness equals the space between threads. This is the critical dimension for thread fit (Tolerance classes 2A/3A for Imperial; 6g/4g6g for Metric).
Minor Diameter – The smallest diameter of the external thread, measured root to root. This represents the core strength of the fastener and is the theoretical maximum diameter of the tap drill.
Thread Pitch – The distance from a point on one thread to the corresponding point on the next.

Hex Head – DIN 933/ISO 4017
Dimension	Size (mm)
Dimension	Min	Max
Width Across Flats	78.1	80
Width Across Corners	88.25	Not specified
Head Height	32.5	33.5

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Frequently Asked Questions

What is the tap drill size for M52 coarse screws or bolts?

For metric fasteners, the recommended tap drill size can be calculated using this formula: Major Diameter – Thread Pitch. For an M52 x 5.0 (Coarse), the recommended tap drill is 47.00mm.

What clearance hole size is needed for an M52 screw or bolt?

For an M52 fastener, a 54.00mm drill bit is utilized for a Close Fit, a 56.00mm bit is used for a Normal Fit, and a 62.00mm bit is recommended for a Loose Fit. A Normal Fit is the industry standard to ensure the massive bolt shank passes through the assembly without binding while maintaining structural alignment.

What is the difference between a bolt and a screw?

The difference is based on the intent of the fastener’s use; If the primary intent is for the fastener to pass through an unthreaded hole and be assembled with a nut, it is a Bolt. In this application, you usually hold the head and turn the nut to apply tension. But if the primary intent is for the fastener to be installed into a threaded (tapped) hole, it is a Screw. In this application, the connection is tightened by turning the head of the fastener itself.