Countersink / Counterbore
mm
inch
Counterbore
socket head cap screw
Countersink
flat head screw
Countersink / Counterbore
The clearance hole and the seat for a socket head or flat head screw, from the standard.
Feature
Counterbore
socket head cap screw
Countersink
flat head screw
Standard
Inch
Metric
Screw size
1/4
Clearance fit
Normal fit is intended for general conventional assembly.
Socket head cap screw — counterbore
Flat head screw — countersink
Inch / Unified
Metric
Normal Fit
Close Fit
Machining feature
Method & sources
Engineering reference only.
Verify critical dimensions, parameters, machine/tool limits and governing specifications before use.
Terms & Disclaimer