Which bit holder do I need — magnetic, quick-change or extension?

These all look like the same small steel tube on the shelf and they do different jobs. Knowing which is which turns a set of frustrations — screws falling off, bits pulling out of the chuck, bits left in the screw head — into three separate solved problems.

Step by step

1. Start with what a magnetic holder does.A magnet in the body magnetises the bit so a steel screw stays on it. That is all it does, and it is transformative overhead, inside cabinets and anywhere a dropped screw is unrecoverable.
2. Understand the quick-change collar.A sprung collar you pull back to release the bit, so you swap sizes in a second without touching the chuck. On a drill this is the single accessory that makes people actually change bits rather than persevere with the wrong one.
3. Understand what locking means.A locking holder grips a groove in the bit so the bit cannot pull out. Without it, a bit that is tighter in the screw than in the holder stays in the screw, which is how bits get left in walls and behind units.
4. Choose an extension for reach, not for convenience.A 150 or 300mm extension gets a bit down into a recess. It also amplifies every degree of misalignment, wobbles visibly and reduces the torque you can apply cleanly. Use it when you must.
5. Match the shank to the tool.For an impact driver, the holder needs a locking groove on its own shank or it will fall out. For a drill chuck, any hex shank works. This is the mismatch that causes most complaints about holders.
6. Consider a bit holder as a depth aid.A holder with an adjustable nose — a screw setter — stops the screw at a set depth, which is what stops plasterboard screws tearing the paper. It is a specialist item that solves one problem completely.
7. Do not stack accessories.An extension into a holder into an adaptor is a wobbling column of tolerances. Each junction adds runout, and by the third one the bit describes a visible circle.
8. Restore magnetism when it fades.Stroke a strong magnet along the holder in one direction several times. It works, it takes ten seconds, and it saves buying another holder.

Tips

• Magnetic holders attract steel swarf and grit, which then jams the collar. Wipe the nose occasionally.
• If a screw will not stay on a magnetic holder, the screw is stainless or brass and is not magnetic at all. Use a screw-holding driver or start it by hand.
• A holder adds 50 to 60mm to the length of the tool. In tight spaces that is exactly the wrong direction, and a short stubby bit direct in the chuck is better.

Alternatives

• Magnetic quick-change holder: The default for a drill. Fast bit changes, holds the screw, and cheap. The one to own if you own only one.
• Locking bit holder: Adds a mechanism that grips the bit's groove. Worth it for impact drivers and for overhead work where a bit left in a screw is a real nuisance.
• Flexible extension: A sprung shaft for reaching round obstructions. Low torque and it whips if pushed, but nothing else reaches where it does.
• Adjustable depth setter: A collar around the bit that stops the screw at a preset depth. The standard answer for plasterboard and for repeat work at a consistent depth.

Questions people ask