screwfitmentdatabase

Thread locker and torque on small screws

Small screws fail in two ways: too loose and they back out with vibration, too tight and they strip the hole. Both are avoidable.

Rough torque guidance

These are starting points for steel screws into steel. Always follow a manufacturer figure when there is one.

  • M1.2: about 5-8 N·cm into steel, 3-5 N·cm into plastic
  • M1.4: about 8-12 N·cm into steel, 4-7 N·cm into plastic
  • M1.6: about 12-20 N·cm into steel, 6-10 N·cm into plastic
  • M2: about 25-40 N·cm into steel, 12-20 N·cm into plastic
  • M2.5: about 45-70 N·cm into steel, 20-35 N·cm into plastic
  • M3: about 80-130 N·cm into steel, 35-60 N·cm into plastic
  • M4: about 2.0-3.0 N·m into steel, 0.8-1.4 N·m into plastic
  • M5: about 4.0-6.0 N·m into steel, 1.5-2.5 N·m into plastic
  • M6: about 7-10 N·m into steel, 2.5-4.0 N·m into plastic

Plastic bosses are a different game

A plastic screw boss holds by friction in soft material. Use roughly half the metal figure, and stop the moment you feel the screw seat.

If a boss has stripped, a slightly larger thread-forming screw or a heat-set brass insert will rescue it.

When to use thread locker

Blue (medium strength) for anything that vibrates: drones, bikes, machinery, motor mounts.

Never red on small screws — you will snap the head trying to remove it.

Skip threadlocker entirely on plastic; many formulas attack polycarbonate and ABS. Use a nylon patch screw or a lock washer instead.

Common questions

Do I need a torque driver for laptop screws?

Not usually. Snug plus a very small nudge is right. A preset 0.3 N·m driver helps if you do repairs often.

Can I reuse a screw with dried threadlocker on it?

Clean the old material off first, otherwise it will not seat properly. A wire brush and a little acetone works.

What holds a screw in vibration without threadlocker?

Nylon insert nuts, split or wave washers, serrated flange heads, or a nylon-patch screw.

Keep reading

How to measure a screw and work out its metric sizeRemoving a stripped tiny screw without wrecking the deviceLaptop screw sizes explainedMetric vs imperial screws — the sizes that fool everyoneScrew head shapes and when each one is rightPutting screws into plastic without stripping itChoosing the right screw lengthWhich screw material to use, and what rustsSecurity screws and how to get them outKeeping track of tiny screws during a repairCross-threaded, seized and spinning screwsWashers, locking methods and screws that will not stay tightHow to buy the right screws onlineOpening a laptop, phone or console without damageScrew standards: ISO, DIN, ANSI and JISIdentifying a screw when the manufacturer never published the sizeChoosing and fitting screws in 3D printed partsEyeglass, watch and hearing aid screwsLicense plate, trim and small automotive screwsAll tools

Tools and screws for this job

Affiliate links — they cost you nothing extra and keep this database free.