M42 bolt or screw dimensions and sizes are massive fasteners essential for heavy industrial foundations, large-scale hydroelectric plants, massive ship engines, and heavy mining excavators. This size has a 42.00mm nominal major diameter and is available in M42 x 4.5 for the coarse series, where 4.5 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., Heavy Hex, Stud Bolts, Anchor Bolts), manufacturer, or material grade — always verify with the official product datasheet before use.
M42 x 4.5 Screw & Bolt – DIN 13-1/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
41.437
41.937
Pitch Diameter
38.778
39.014
Minor Diameter
36.006
37.066
Thread Pitch
4.5
Major Diameter
41.437
41.937
Pitch Diameter
38.864
39.014
Minor Diameter
36.092
37.066
Thread Pitch
4.5
M42 x 4.0 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
41.465
41.94
Pitch Diameter
39.118
39.342
Minor Diameter
36.654
37.61
Thread Pitch
4.0
Major Diameter
41.465
41.94
Pitch Diameter
39.202
39.342
Minor Diameter
36.738
37.61
Thread Pitch
4.0
M42 x 3.0 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
41.577
41.952
Pitch Diameter
39.803
40.003
Minor Diameter
37.955
38.704
Thread Pitch
3.0
Major Diameter
41.577
41.952
Pitch Diameter
39.878
40.003
Minor Diameter
38.03
38.704
Thread Pitch
3.0
M42 x 2.0 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
41.682
41.962
Pitch Diameter
40.493
40.663
Minor Diameter
39.261
39.797
Thread Pitch
2.0
Major Diameter
41.682
41.962
Pitch Diameter
40.557
40.663
Minor Diameter
39.325
39.797
Thread Pitch
2.0
M42 x 1.5 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
41.732
41.968
Pitch Diameter
40.844
40.994
Minor Diameter
39.92
40.344
Thread Pitch
1.5
Major Diameter
41.732
41.968
Pitch Diameter
40.899
40.994
Minor Diameter
39.975
40.344
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 M42 screws or bolts?
For metric fasteners, the recommended tap drill size can be calculated using this formula: Major Diameter – Thread Pitch. For an M42 x 4.5 (Coarse), the recommended tap drill is 37.50mm.
What clearance hole size is needed for an M42 screw or bolt?
For an M42 fastener, a 43.00mm drill bit is utilized for a Close Fit, a 45.00mm bit is used for a Normal Fit, and a 48.00mm 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.
