M64 screw or bolt dimensions and sizes represent some of the largest standard metric fasteners, critical for heavy structural baseplates, industrial forging presses, massive maritime assemblies, and primary foundation anchoring. This size has a 64.00mm nominal major diameter and is available in M64 x 6.0 for the coarse series, where 6.0 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.
M64 x 6.0 Screw & Bolt – DIN 13-1/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
63.32
63.92
Pitch Diameter
59.743
60.023
Minor Diameter
56.047
57.425
Thread Pitch
6.0
Major Diameter
63.32
63.92
Pitch Diameter
59.843
60.023
Minor Diameter
56.147
57.425
Thread Pitch
6.0
M64 x 4.0 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
63.465
63.94
Pitch Diameter
61.106
61.342
Minor Diameter
58.642
59.61
Thread Pitch
4.0
Major Diameter
63.465
63.94
Pitch Diameter
61.192
61.342
Minor Diameter
58.728
59.61
Thread Pitch
4.0
M64 x 3.0 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
63.577
63.952
Pitch Diameter
61.791
62.003
Minor Diameter
59.943
60.704
Thread Pitch
3.0
Major Diameter
63.577
63.952
Pitch Diameter
61.871
62.003
Minor Diameter
60.023
60.704
Thread Pitch
3.0
M64 x 2.0 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
63.682
63.962
Pitch Diameter
62.483
62.663
Minor Diameter
61.251
61.797
Thread Pitch
2.0
Major Diameter
63.682
63.962
Pitch Diameter
62.551
62.663
Minor Diameter
61.319
61.797
Thread Pitch
2.0
M64 x 1.5 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
63.732
63.968
Pitch Diameter
62.834
62.994
Minor Diameter
61.91
62.344
Thread Pitch
1.5
Major Diameter
63.732
63.968
Pitch Diameter
62.894
62.994
Minor Diameter
61.97
62.344
Thread Pitch
1.5
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.
What is the tap drill size for M64 coarse screws or bolts?
For metric fasteners, the recommended tap drill size can be calculated using this formula: Major Diameter – Thread Pitch. For an M64 x 6.0 (Coarse), the recommended tap drill is 58.00mm.
What clearance hole size is needed for an M64 screw or bolt?
For an M64 fastener, a 66.00mm drill bit is utilized for a Close Fit, a 70.00mm bit is used for a Normal Fit, and a 74.00mm 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.
