a tool for enlarging a drilled hole for a portion of its length, as to permit sinking a screw head.
the portion of the hole so enlarged.
to enlarge (a drilled hole) along part of the length of the hole by drilling with a bit having a greater diameter.
- coun·ter·bor·er, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024
How to use counterbore in a sentence
That it may always do this and yet leave sufficient clearance, the counterbore has been devised.Farm Engines and How to Run Them | James H. Stephenson
The jaw end is counterbored out with a 45-degree counterbore to form a bearing for the forward end of the micrometer screw.Measuring Tools | Unknown
For enlarging a hole for a certain distance the counterbore is employed.Modern Machine-Shop Practice, Volumes I and II | Joshua Rose
A counterbore in the arbor hub provides clearance for the hub of the pulley which projects beyond the rim on one side.Turning and Boring | Franklin D. Jones
For counterboring small holes or for facing the metal around their ends, the form of counterbore shown in Fig. 1746 is employed.Modern Machine-Shop Practice, Volumes I and II | Joshua Rose