M30 bolt or screw dimensions and sizes are heavy-duty industrial fasteners essential for large-scale construction, bridge pylons, heavy engine mounting, and industrial crane tracks. This size has a 30.00mm nominal major diameter and is available in M30 x 3.5 for the coarse series and M30 x 2.0 for the fine series, where 3.5 and 2.0 represent the thread pitch in millimeters. This reference chart follows respective DIN and ISO standards for each head style and DIN 13-1 (coarse), DIN 13-21 (fine), 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., Hex Head, Heavy Hex, Stud Bolts), manufacturer, or material grade — always verify with the official product datasheet before use.
M30 x 3.5 Screw & Bolt – DIN 13-1/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
29.522
29.947
Pitch Diameter
27.462
27.674
Minor Diameter
25.306
26.158
Thread Pitch
3.5
Major Diameter
29.522
29.947
Pitch Diameter
27.542
27.674
Minor Diameter
25.386
26.158
Thread Pitch
3.5
M30 x 2.0 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
29.682
29.962
Pitch Diameter
28.493
28.663
Minor Diameter
27.261
27.797
Thread Pitch
2.0
Major Diameter
29.682
29.962
Pitch Diameter
28.557
28.663
Minor Diameter
27.325
27.797
Thread Pitch
2.0
M30 x 1.5 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
29.732
29.968
Pitch Diameter
28.844
28.994
Minor Diameter
27.92
28.344
Thread Pitch
1.5
Major Diameter
29.732
29.968
Pitch Diameter
28.899
28.994
Minor Diameter
27.975
28.344
Thread Pitch
1.5
M30 x 1.0 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
29.794
29.974
Pitch Diameter
29.199
29.324
Minor Diameter
28.583
28.891
Thread Pitch
1.0
Major Diameter
29.794
29.974
Pitch Diameter
29.244
29.324
Minor Diameter
28.628
28.891
Thread Pitch
1.0
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.
What is the tap drill size for M30 screws or bolts?
For metric fasteners, the recommended tap drill size can be calculated using this formula: Major Diameter – Thread Pitch. For an M30 x 3.5 (Coarse), the recommended tap drill is 26.50mm. For an M30 x 2.0 (Fine), the recommended drill size is 28.00mm.
What clearance hole size is needed for an M30 screw or bolt?
For an M30 fastener, a 31.00mm drill bit is utilized for a Close Fit, a 33.00mm bit is used for a Normal Fit, and a 35.00mm bit is recommended for a Loose Fit. A Normal Fit is the industry standard to ensure the large 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.
