Metric clearance Hole

 

A through hole or clearance hole for a screw is a common design in fastening technology. It allows the screw to pass through the workpiece to make a connection on the opposite side. The through hole has a specific size that aims to adequately accommodate the screw and ensure a stable connection.

There are three common ways to make a through hole for a screw. These options are based on different tolerance grades and determine the exact size of the hole:

 

Fine: The through hole with a fine tolerance grade provides a precise fit to ensure an optimal connection with the screw. It ensures high accuracy and a tight fit between the screw and the workpiece.

Medium: The through hole with a medium tolerance class provides some clearance and allows more flexible positioning of the screw. It is suitable for applications where a slightly larger tolerance is acceptable or when a precise fit is not essential.

Coarse: The through hole with a coarse tolerance grade provides the greatest clearance and allows a looser fit. It can be useful when a loose fit is sufficient or when some room for movement is desired.

 

Please note that exact diameters and tolerances may vary depending on requirements, standards and specific applications. It is important to consult the exact specifications and requirements of appropriate standards or engineering drawings to determine the correct size of through hole for the appropriate screw.

 

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metric clearance hole, metric through hole, screw
metric clearance hole

 

The picture on the left shows a through hole for a cylinder head screw. In order to connect workpiece 1 with workpiece 2, a through hole is drilled in workpiece 1. The correct diameter can be found in the following through-hole table.

Clearance Hole Chart for metric sizes (Through Hole Chart)

Metric thread sizes

Fine

(mm)

Medium

(mm)

Coarse

(mm)

 M1  1,1 1,2 1,3
M1,2 1,3 1,4 1,5
M1,4 1,5 1,6 1,8
M1,6 1,7 1,8 2
M1,8 2 2,1 2,2
M2 2,2 2,4 2,6
M2,5 2,7 2,9 3,1
M3 3,2 3,4 3,6
M3,5 3,7 3,9 4,2
M4 4,3 4,5 4,8
M5 5,3 5,5 5,8
M6 6,4 6,6 7
M8 8,4 9 10
M10 10,5 11 12
M12 13 13,5 14,5
M14 15 15,5 16,5
M16 17 17,5 18,5
M18 19 20 21
M20 21 22 24
M22 23 24 26
M24 25 26 28
M27 28 30 32
M30 31 33 35
M36 37 39 42
M42 43 45 48
M48 50 52 56
M56 58 62 66
M64 66 70 74

* All information without guarantee.

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