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How to use a Torx screwdriver without rounding the screw

Updated: October 2026

You already have a driver and a star screw that still has clean lobes. The job is to seat the matching tip square, turn it by hand until it moves, and stop the moment the tip starts to climb out. That is how to use a Torx screwdriver on a housing, a bike part or a cover. Our [Torx screwdriver set comparison](/hub/hand-tools/torx-screwdriver-set) is where the sets are listed. The Products Compared editorial team wrote this from those amazon.co.uk review themes and public UK sources on 15 October 2026, not from a lab. A qualifying purchase can earn a commission at no extra cost to you.

You already have a driver and a star screw that still has clean lobes. The job is to seat the matching tip square, turn it by hand until it moves, and stop the moment the tip starts to climb out.

Our top picks

SWANLAKE GARDEN TOOLS SWANLAKE 13-piece Torx set T5–T40

Best overall

SWANLAKE GARDEN TOOLS SWANLAKE 13-piece Torx set T5–T40
8.9/10about £11.99
View offer
GURADESIGN GURADESIGN 13-piece Torx set T5–T40

Best value

GURADESIGN GURADESIGN 13-piece Torx set T5–T40
8.7/10about £9.89
View offer
Amtech Amtech L0530 6-piece precision Torx set

Alternative

Amtech Amtech L0530 6-piece precision Torx set
6.1/10about £5.02
View offer
On this page
  1. 1.Match the size code, do not guess from millimetres
  2. 2.Look for a centre pin before you turn
  3. 3.Keep the driver in line, and use the magnet block if the set has one
  4. 4.Stop, and know the jobs that are not yours

Match the size code, do not guess from millimetres

Read the stamp on the screw and the stamp on the driver, and use the pair that matches. The T-number is not a millimetre you can check with a ruler. ISO 10664 gives T20 as 3.95 mm point to point, so a ruler will not pick the size. A driver one size down often feels almost right and still rounds the head. Screwfix’s guide asks you to identify Torx before you confuse it with a Phillips or a hex key. That mix-up is Torx, Pozidriv or Phillips. If T20 is slack and T25 will not enter, stop. Amtech reviews include a T5 tip that warped on laptop screws. If you do not own the stamped size, the buying guide is the detour, not a harder push.

Look for a centre pin before you turn

Before the first turn, look into the star. A small post in the middle is a security screw. A solid tip bottoms on that post and will not turn the screw. You need a bored tip of the same T-code, and the listing has to say that size is bored. The US PRO set says its T8 is not tamper-proof. Which driver fits which screw is on the security Torx and standard Torx page. Do not drill the pin out. Vacuum and washer covers are on the appliance page. Match the pin, then the size, then keep the driver in line.
SWANLAKE GARDEN TOOLS SWANLAKE 13-piece Torx set T5–T40

Testsieger

SWANLAKE GARDEN TOOLS SWANLAKE 13-piece Torx set T5–T40
8.9/10about £11.99
View offer

Keep the driver in line, and use the magnet block if the set has one

Put the tip fully into the recess and keep the shaft in line with the screw. A slanted driver climbs out even when the size is right. Press in as you turn. Most screws undo anticlockwise. If nothing starts, check the size and the pin before you change direction. Several sets that say magnetic arrive with a block you have to use. SWANLAKE reviews say the tips do not hold a screw until that block has been drawn along the blade. Use the demagnetiser where the set includes one. Seat and start the screw by hand. A drill keeps spinning after the lobes let go, so it is a later choice on a screw that is already turning freely. One GURADESIGN reviewer used a light tap on the hard end of a full-size handle. That is not a hammer method, and it does not belong on a precision bit.

Stop, and know the jobs that are not yours

Stop at the first climb-out. If the driver jumps, the lobes are already losing their shape. This page does not cover extractors. Fit the right size, or leave the screw. Unplug a mains appliance and do not start if you cannot show that it is dead. Leave gas appliances alone. Leave brakes, steering, suspension and airbags to someone qualified for that work. At work, the Health and Safety Executive’s PUWER overview expects the employer to provide suitable equipment and to have instructed the user. That duty is not permission to improvise on a restraint system.

Common questions

How do I know the driver is the right size?
The stamps match, and the tip sits fully in the recess without rocking. One size down can feel close and still bear on the corners. If the next size up will not enter and the current one slops, you have the wrong driver. Pressing harder is how a T5 tip in the Amtech reviews warped a laptop screw.
The set says magnetic, but the screw will not stick. What now?
Use the magnetising block if the set has one. SWANLAKE reviews say the tips are not magnetic until that block is used. A demagnetiser, where it is included, takes the pull off when you need to leave a screw in place. If the tip still falls out, the size or the angle is wrong.
Should I use a drill?
Start by hand so you can feel the tip climb. A drill keeps turning after the lobes let go. Once the screw is moving freely and the tip is seated, a slow drill can finish a long fastener. Do not use a drill to test sizes, or on a precision bit the listing says is not for large screws.
When do I stop so I do not round the head?
Stop as soon as the tip climbs out or the handle turns while the screw does not. Reseating the same undersize driver finishes the damage. Fit the stamped size, square to the screw, and press in as you turn. If the head is already rounded, this guide does not move on to extractors.
When is this no longer a DIY job?
Stop for gas appliances, for brakes, steering, suspension and airbags, and for any mains appliance you cannot prove is dead. A screw that is already rounding belongs with a qualified person. At work, instruction is the employer’s duty under PUWER. Owning a T20 driver does not make those jobs safe.

Related pages

Torx screwdriver sets 2026

Best Torx screwdriver set UK: who each pick is for

Torx screwdriver set buying guide: size, pin, form

Torx screwdriver for appliances: start at the screw

Security Torx vs Torx: the centre pin decides the tip

Sources

Public UK sources and the amazon.co.uk listings in this comparison. Method dated 15 October 2026. Page updated October 2026.

  1. ISO 10664:2014 hexalobular internal driving feature (retrieved 15 October 2026)
  2. HSE: PUWER overview (retrieved 15 October 2026)
  3. GOV.UK: General Product Safety Regulations 2005, Great Britain (retrieved 15 October 2026)
  4. Consumer Rights Act 2015, section 9 (retrieved 15 October 2026)
  5. Screwfix: types of screwdrivers (retrieved 15 October 2026)
  6. Insight Security: what is a Torx screw (retrieved 15 October 2026)
  7. Bosch DIY: Torx screwdriver set 1600A02BX6 (retrieved 15 October 2026)
  8. Wonkee Donkee: what are sockets made of (retrieved 15 October 2026)