How to choose the right screwdriver bit?

A bit that slips, a screw head that rounds off, and screwing becomes a chore. To understand how to choose the right screwdriver bit, you need to consider five criteria: the shape of the recess, its size, accessibility to the screw, compatibility with the tool, and the condition of the material. A more powerful screwdriver will not compensate for a poorly suited bit.

Here is a method for common furniture and small wooden piece assemblies, excluding electrical work or safety fixings. The objective is simple: achieve solid contact in the head, maintain the axis, and stop before damaging the screw.

1. Recognize the recess instead of choosing "approximately"

Clean the screw head and observe it under good lighting. A recess filled with paint or dust may appear smaller than it is. The bit's profile must match the actual shape of the head, not just fit into its center.

Phillips head screws require particular attention. Phillips, denoted PH, and Pozidriv, denoted PZ, are two different profiles. On a Pozidriv screw, small additional markings between the main branches often help identify it. A PH bit may seem to fit into a PZ head, but it will offer poor support.

For a six-lobe recess, look for the exact designation: TORX and TORX PLUS are not synonymous. An internal hex head requires a corresponding hex bit. Security screws with a central pin also require a specific profile.

If the profile remains doubtful, check the screw packaging or furniture documentation. Avoid trying several bits successively by running the machine. Identification should be done while the tool is off: a motorized test with the wrong profile can damage the head even before assembly begins.

2. Choose the size that correctly fills the head

Within the same family, several sizes exist. The number after PH or PZ indicates a recess size; it does not directly correspond to the screw body diameter. Similarly, a TORX size is selected according to the head, not the screw length.

Present the bit without starting the screwdriver. It should sink into the recess and rest on its useful faces. A bit that is too small leaves significant play; too large, it remains perched on the head. Neither should be "adjusted" by applying more pressure.

On a new, removed screw, lightly check the fit with your fingers, without using the tip as a lever. If the screw is already damaged, a good size may still not hold well. Replace the fastener when possible rather than mistaking a worn recess for a dimension problem.

An assortment like the Makita B-55697 kit allows you to compare several profiles and sizes without improvising. Its manufacturer's sheet specifies 43 accessories: 38 bits, three socket adapters, and two bit holders. So it's not 43 different tips.

3. Adapt the length and bit holder to the access

A screw accessible from the front does not require the same equipment as a fastener deep within a recess. Look at the available space around the head: a bit holder that is too wide can touch the furniture before the tip reaches the bottom of the recess.

Choose a sufficient length to reach the screw, without unnecessarily adding several extensions. The longer the assembly, the more difficult it becomes to perceive and correct an inclination. Check that nothing rubs against the decor when you present the tool on its axis.

The bit holder must accept the shank of the accessory and retain it according to its operation. A magnetic retention is not the same as a mechanical lock. Ensure that the bit is properly engaged, then check its hold when the tool is stopped. Do not use an assembly whose elements only interlock by a few millimeters.

Very narrow access may make a manual handle more appropriate than a screwdriver. Maintaining a correct angle is more important than saving a few seconds. Do not deliberately screw at an angle to avoid moving a board or clearing the way: the bit can slip and mark the surface.

4. Check the tool and start with a cautious setting

A common screwdriver bit is not automatically intended for an impact driver. Look for explicit compatibility announced for the bit and bit holder concerned. The presence of a case or a color on the tip is not enough to confirm this use.

On a drill/driver, choose the appropriate screwing mode, without percussion. Start at a low speed and with a cautious torque setting, then adjust on a comparable scrap piece if necessary. The numbers on the collar do not constitute a universal value in Newton-meters: their effect varies depending on the machine and the assembly.

Immobilize the pieces with suitable support. Place the tip in the head before starting, align the tool with the screw's axis, and maintain steady pressure. Fingers that initially held the screw must leave the rotation zone. Avoid loose clothing and accessories that could get tangled.

If the bit comes out of the recess, stop immediately. Check the profile, size, alignment, and resistance of the assembly. Repeating the slippage by accelerating increases the damage. A pilot hole may be necessary depending on the screw, material, and assembly instructions; it is not the bit's job to compensate for poorly prepared material.

5. Inspect and store bits after use

Examine the tips under light. Rounded edges, deformation, a chip, or repeated signs of slippage justify replacing the bit. A worn tip can damage several new screws before the defect is identified.

Clean residues without altering the profile. Do not try to transform a worn tip into a bit of another size with a grinder. The contact surfaces have a precise geometry; an improvised touch-up makes the fit unpredictable.

Replace accessories in their dry and clean slots. Color codes facilitate identification within an assortment, but they are not a common standard across all brands. Always read the profile and size marking. For repetitive assemblies, keep an identical spare bit handy.

Before the next project, count the small accessories used and separate damaged items. An organized kit is primarily for quickly selecting the right tip, not for accumulating bits whose condition or function is unknown.

The right reflex: choosing the right screwdriver bit means matching an identified recess, an adjusted size, and well-aligned access. Find Manuzen screwdriver bits and accessories to only complete the profiles useful for your assemblies.

Technical sources: official composition of the Makita B-55697 kit and recess families presented by Wiha.

Guide documented on September 12, 2026. Illustrative scenarios; always check the manual and the chosen variant.