A magnetic screwdriver has a magnetised tip that holds ferrous (iron/steel) screws in place during driving. This keeps both hands free, prevents dropped screws in hard-to-reach spots, and makes starting fasteners dramatically easier - especially overhead or in tight spaces.
How Magnetic Tips Work
There are two main ways a screwdriver tip becomes magnetic:
- Permanent magnetism - the tip is made from or treated with a material that retains a magnetic field. Chrome vanadium and S2 steel tips can be permanently magnetised during manufacturing. The magnetism weakens slowly over years of use but lasts a long time.
- Induced magnetism (rare-earth magnet insert) - a small neodymium magnet is embedded in the bit holder or shaft. The magnet induces a temporary magnetic field in the bit and screw. The bit itself is not permanently magnetised, so the effect disappears when you remove the bit from the holder.
Magnetiser / Demagnetiser Tools
A magnetiser/demagnetiser is a small block (usually about 40 x 30 x 25 mm) containing two opposing magnets. Slide a screwdriver shaft through the "magnetise" slot and the domains in the steel align, creating a magnetic tip. Slide it through the "demagnetise" slot and the domains are scrambled, removing the magnetic field. These cost a few dollars and work on any steel driver or bit.
When Magnetic Tips Help
- Starting screws one-handed or overhead
- Working inside deep recesses where screws drop and get lost
- Precision electronics assembly with tiny screws
- Retrieving dropped ferrous screws from tight spaces
When to Avoid Magnetic Tips
- Near magnetic storage media (hard drives during repair) - the magnetic field can corrupt data
- Working with sensitive electronic components like magnetic sensors, Hall effect sensors, or pacemaker circuitry
- In environments where metallic debris collection is a problem (food processing, cleanroom)
- With stainless steel or brass screws - non-ferrous materials are not attracted to magnets
Keep a magnetiser/demagnetiser in your toolbox. Magnetise your drivers for general work, then demagnetise before working on sensitive electronics. It takes two seconds.
