Harry Houdini
Aerospace
- Jan 22, 2021
- 18
Hello everyone, hoping someone could point me in the right direction. I am currently aggregating all possible information regarding clearance hole sizing for a fixed fastener calculator. See image below.
All of the values in the tables are based off ASME B18.2.8-1999 which can also be found in the Machinery's Handbook. See images below.
This is what my calculator looks like, but I am missing information regarding minimum counterbore diameter for pan heads, button heads. I can get the MAX head diameter of the different screw types either from NAS or Machinery's Handbook. I could also calculate what the minimum CB diameter could be for a specified position tolerance, but that seems kind of arbitrary. Also I use Soliwroks as a CAD program but the clearance hole values seem to not correlate to any standard.
My question is, is there a standard out there that talks about counterbore depth and width for different fastener types?
Also for anyone who is curious, this is what the calculator looks like.

All of the values in the tables are based off ASME B18.2.8-1999 which can also be found in the Machinery's Handbook. See images below.

This is what my calculator looks like, but I am missing information regarding minimum counterbore diameter for pan heads, button heads. I can get the MAX head diameter of the different screw types either from NAS or Machinery's Handbook. I could also calculate what the minimum CB diameter could be for a specified position tolerance, but that seems kind of arbitrary. Also I use Soliwroks as a CAD program but the clearance hole values seem to not correlate to any standard.
My question is, is there a standard out there that talks about counterbore depth and width for different fastener types?
Also for anyone who is curious, this is what the calculator looks like.
