Drill bits and accessories: what belongs in the box?

Start with the hole, not the set

Before buying a drill bit, work out what material you need to drill, what the hole is for and which tool will make it. A bit intended for wood is not a general answer to every surface. Masonry bits are designed for masonry, while other materials need accessories intended for their own applications.

The job also determines the diameter and depth you need. Those requirements may come from a fixing or component manufacturer. Read that information first rather than choosing a bit that looks close enough. If the material is uncertain, identify it before selecting an accessory.

Understand the common names

A pilot hole is a smaller hole used to guide a screw and help reduce splitting. A countersink is a cone-shaped recess that lets an appropriate screw head sit flush with or below the surface. These are different purposes, even when both appear in the same project.

An auger bit is intended for relatively deep holes in wood. A masonry bit is designed for masonry and often has a carbide-tipped cutting end. The name is a useful starting point, but it does not replace the accessory’s stated applications, size limits or instructions. Avoid assuming a bit is suitable because it has the right diameter.

Check the connection to the tool

The part of an accessory held by the tool is its shank. Its shape and size must suit the tool’s holder or chuck. An adjustable drill chuck and a quick-release hex holder are different arrangements. A bit fitting physically does not establish that the whole combination is suitable for the task.

Check the exact tool manual and accessory packaging. Some systems need a particular fitting, and accessories can have limits on operating mode or speed. Do not improvise an adapter to force a combination the manufacturer has not approved. Keep the compatibility information with the accessory if it is easy to confuse with another one.

Keep drilling and driving separate

A drill bit makes a hole. A screwdriver bit engages with the head of a fixing. The correct driving bit needs to match the recess type and size; a poor match can damage both the fixing and the bit. A collection of nearly right tips is less useful than a few suitable ones in good condition.

If you use an impact driver, choose accessories rated for that use. Do not assume every hex-shank accessory is impact suitable. Check the tool and accessory instructions together, including any limits on extension holders or other parts between the tool and the working tip.

Buy for a real list of jobs

Write down the materials and fixing sizes your next project actually needs. That gives you a way to compare a small set with buying individual accessories. Consider replacements as well: an everyday size that is easy to buy again may matter more than several unusual sizes you will rarely touch.

Look at the case and labels too. Being able to identify a bit and return it to the right place saves uncertainty next time. A clear size marking and readable application information are more useful than a high piece count on the front of the box.

• Check material suitability.
• Check diameter, useful working length and fitting.
• Check tool, operating mode and accessory compatibility.
• Keep the instructions and size information.

Condition and workholding still matter

An unsuitable or damaged accessory can spoil the job even when the drill itself is capable. Inspect accessories before use and replace damaged ones according to the manufacturer’s guidance. Stop if the setup is behaving unexpectedly rather than trying to solve the problem with more force.

The workpiece also needs appropriate support and restraint. Plan workholding and suitable protection alongside the bit purchase. Before drilling into a building surface, check the substrate and possible hidden services; this buying guide does not establish that any particular drilling location is safe.

The takeaway

• Match the accessory to the material and purpose of the hole.
• Check the exact fitting and manufacturer compatibility guidance.
• Driving bits and drill bits do different jobs.
• Choose useful sizes and clear labels over a large piece count.