Key takeaways
- Coarse thread for timber studs, fine thread for light steel studs, drill point for steel heavier than 0.9 mm.
- Penetrate at least 16 mm into timber or 10 mm past steel.
- Phosphate screws are for dry interiors; use zinc or cement board screws in damp areas.
Drywall screws look alike, but the thread decides what they hold in. Picking the wrong one is the most common reason for popped screws and stripped studs.
Coarse thread: timber studs
Coarse, widely spaced threads grab wood fibres and pull the board tight. They are also the default for general woodworking with drywall screws.
Fine thread: steel studs
Thin steel studs (0.5–0.8 mm) do not have enough material for a coarse thread. Fine threads put more thread turns into the steel and hold without stripping. A sharp point pierces the stud.
Drill point: heavier steel
For 0.9–2.5 mm steel, a drywall screw with a #2 drill point prevents the screw from skating across the stud face.
Choosing a length
| Board | Timber studs | Steel studs |
|---|---|---|
| 9.5 mm | 3.5 × 25 mm | 3.5 × 25 mm |
| 12.5 mm | 3.5 × 32 mm | 3.5 × 25 mm |
| 2 × 12.5 mm | 3.9 × 41–51 mm | 3.5 × 41 mm |
Loose or collated
On commercial jobs, collated screws on plastic strips save labour and give consistent countersink depth. Make sure the strip pitch fits the auto-feed tool your crews use.
Frequently asked questions
Can I use fine thread screws in wood?
They will hold in hardwood but tend to strip in softwood studs. Use coarse thread for timber.
Why do drywall screws snap?
Usually over-hard heat treatment or driving at too high a torque. Good drywall screws balance a hard surface with a tougher core.
