About Counterbores
![](https://www.mcmaster.com/prerenderstable/mvPRE/contents/gfx/small/a2bga60_abbr.png?ver=1276007986)
Counterboring—Enlarge the top of an existing hole to create a cylindrical-shaped opening with a flat bottom that acts as a seat for the head of a screw or wood plug.
More
Drill-Bit Counterbore Sets
![](/prerenderstable/mvPRE/contents/gfx/imagecache/310/3105a31p1-a02b-digital@halfx_637072655282895624.png?ver=imagenotfound)
Convert standard jobbers’ or brad-point drill bits into counterboring drill bits for drilling and counterboring in one step.
For technical drawings and 3-D models, click on a part number.
Sizes Included | Number of Pieces | For Use On | Container Type | Each | |
Uncoated Steel | |||||
---|---|---|---|---|---|
3/16", 1/4", 5/16", 3/8", 7/16", 1/2" | 6 | Plastic, Wood | Wood Stand | 0000000 | 0000000 |