Hole fit
Pick the fit first
Choose close, normal, loose, or free fit based on assembly tolerance and location needs.
Hole size and fastener reference
Counterbore Hole Size Chart for Low Socket Head Screws (DIN 7984)
Search Counterbore Hole Size Chart for Low Socket Head Screws (DIN 7984) for quick fastener hole sizing, drawing checks, machining setup, and design review.
Fastener hole reference
Search Counterbore Hole Size Chart for Low Socket Head Screws (DIN 7984)
Filter the chart by fastener size, hole diameter, fit class, counterbore diameter, countersink size, or depth.
Machining check
Check head clearance
Use counterbore or countersink dimensions to confirm the screw head seats as intended.
Reference table
Counterbore hole chart - DIN 7984
| Fastener Size | Pilot Hole Diameter (mm) | Counterbore Diameter (mm) | Counterbore Depth (mm) | ||
|---|---|---|---|---|---|
| Close Fit (H12) | Normal Fit (H13) | Loose Fit (H14) | |||
| M4 | 4.3 | 4.5 | 4.8 | 8.0 | 3.3 |
| M5 | 5.3 | 5.5 | 5.8 | 10.0 | 4.3 |
| M6 | 6.4 | 6.6 | 7.0 | 11.0 | 4.8 |
| M8 | 8.4 | 9.0 | 10.0 | 15.0 | 5.8 |
| M10 | 10.5 | 11.0 | 12.0 | 18.0 | 7.3 |
| M12 | 13.0 | 13.5 | 14.5 | 20.0 | 8.3 |
| M16 | 17.0 | 17.5 | 18.5 | 26.0 | 10.8 |
| M20 | 21.0 | 22.0 | 24.0 | 33.0 | 13.0 |
| M24 | 25.0 | 26.0 | 28.0 | 40.0 | 15.0 |
| M30 | 31.0 | 33.0 | 35.0 | 50.0 | 18.5 |
| M36 | 37.0 | 39.0 | 42.0 | 58.0 | 22.5 |
How to use
Practical checks for fastener holes
Clearance
C = Dhole - Dfastener
Positive clearance gives assembly room between the fastener shank and the hole.
Counterbore depth
depth ≥ head height + allowance
Counterbore depth should seat the head with the required flush, recessed, or proud condition.
Countersink diameter
D = d + 2h tan(θ/2)
Countersink diameter depends on screw head diameter, depth, and included angle.
Fit selection
close < normal < loose
Tighter fits improve location control; looser fits improve assembly tolerance and speed.
Definitions
What the hole size values mean
Pilot Hole
The through hole for the screw or bolt shank before counterboring or countersinking.
Counterbore Diameter
The flat-bottom recess diameter used to seat a cylindrical screw head or washer face.
Counterbore Depth
The recess depth that controls whether the fastener head sits flush, below, or above the surface.
Countersink Angle
The included cone angle used for flat head screws and countersunk fasteners.
FAQ
Counterbore Hole Size Chart for Low Socket Head Screws (DIN 7984) questions
How should I use this hole size chart?
Use it for quick fastener hole sizing, drawing checks, and machining setup planning.
What is the difference between close, normal, and loose fit?
Close fits provide better location control, normal fits suit typical assembly, and loose fits give more clearance for alignment or tolerance stack-up.
Can this chart replace the fastener standard?
No. Use it as a fast reference; final hole dimensions should follow the current standard, drawing notes, tolerance requirements, and manufacturing process.
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