M27 screw or bolt dimensions and sizes are heavy-duty fasteners primarily found in large-scale structural steel foundations, heavy maritime equipment, mining machinery, and industrial turbine housings. This size has a 27.00mm nominal major diameter and is available in M27 x 3.0 for the coarse series and M27 x 2.0 for the fine series, where 3.0 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, Anchor Bolts), manufacturer, or material grade — always verify with the official product datasheet before use.
M27 x 3.0 Screw & Bolt – DIN 13-1/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
26.577
26.952
Pitch Diameter
24.803
25.003
Minor Diameter
22.955
23.704
Thread Pitch
3.0
Major Diameter
26.577
26.952
Pitch Diameter
24.878
25.003
Minor Diameter
23.03
23.704
Thread Pitch
3.0
M27 x 2.0 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
26.682
26.962
Pitch Diameter
25.493
25.663
Minor Diameter
24.261
24.797
Thread Pitch
2.0
Major Diameter
26.682
26.962
Pitch Diameter
25.557
25.663
Minor Diameter
24.325
24.797
Thread Pitch
2.0
M27 x 1.5 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
26.732
26.968
Pitch Diameter
25.844
25.994
Minor Diameter
24.92
25.344
Thread Pitch
1.5
Major Diameter
26.732
26.968
Pitch Diameter
25.899
25.994
Minor Diameter
24.975
25.344
Thread Pitch
1.5
M27 x 1.0 Screw & Bolt – DIN 13-21/ISO 68-1
Dimension
Size (mm)
Min
Max
Major Diameter
26.794
26.974
Pitch Diameter
26.199
26.324
Minor Diameter
25.583
25.891
Thread Pitch
1.0
Major Diameter
26.794
26.974
Pitch Diameter
26.244
26.324
Minor Diameter
25.628
25.891
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 M27 screws or bolts?
For metric fasteners, the recommended tap drill size can be calculated using this formula: Major Diameter – Thread Pitch. For an M27 x 3.0 (Coarse), the recommended tap drill is 24.00mm. For an M27 x 2.0 (Fine), the recommended drill size is 25.00mm.
What clearance hole size is needed for an M27 screw or bolt?
For an M27 fastener, a 28.00mm drill bit is utilized for a Close Fit, a 30.00mm bit is used for a Normal Fit, and a 32.00mm bit is recommended for a Loose Fit. A Normal Fit is the industry standard to ensure the 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.
