DIY TIPS

How to Make a Custom Counterbore Using a Discarded Hex Bolt

Transform a discarded hex bolt into a custom counterbore tool by securing a self-drilling screw into its head and chucking the bolt shank into your drill. This zero-dollar workshop hack creates an effective cutting tool to recess hardware perfectly flush into wood surfaces. It saves you from buying expensive specialized drill bits while delivering clean, professional results.

A close-up of a DIY countersink drill bit tool made by welding a self-drilling screw onto a hex bolt head, clamped in a drill chuck to create a perfect countersink hole on a wooden block with wood shavings around | HomeDIYer

Author

pipi

June 22, 2026

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Materials List

Hex Bolt
Self-Drilling Screw
Angle Grinder
Power Drill
Hammer

图片

DIY countersink bit materials including an old hex bolt, self-drilling screw, angle grinder, cordless drill, and hammer arranged on a workshop workbench | HomeDIYer

Step-by-Step Guide

Step 1: Locate the Center Point.

Use an angle grinder to cut a cross-shaped groove into the head of the old hex bolt. This helps accurately locate the center point.

Step 2: Bore the Pilot Hole.

Align your power drill with the marked center point and bore a clean, straight screw hole directly into the hex head.

Step 3: Hammer for a Secure Fit.

Position the self-drilling screw over the newly drilled hole and use a hammer to drive it firmly into the bolt head.

Step 4: Chuck and Drive.

Insert the threaded bolt shank backward into your power drill chuck and tighten it down, using the exposed screw tip like an electric screwdriver for your flush-fitting tasks.

Give this clever hardware mashup a try on your next project, and let us know how clean your flush pockets turned out!