Short answer
Use coarse-thread drywall screws on wood studs and fine-thread drywall screws on light-gauge metal studs. That is the simple rule most manufacturers and suppliers give. A common size for 1/2-inch drywall is a #6 screw about 1-1/4 inches long, though thicker board and heavier framing call for different lengths.
Coarse thread drywall screws
Coarse screws have widely spaced threads and a sharp point that bites into wood fibers. They pull the board tight against wood framing without a pilot hole. In the trade they are often called type W screws. Use them for wood studs and joists.
Fine thread drywall screws
Fine screws have closely spaced, shallow threads and a sharp point (or a self-drilling tip) designed to bite into thin steel. They are commonly called type S. Coarse threads tend not to grip thin metal well, so a coarse screw in a metal stud can spin or fail to hold.
What is a type S screw?
Type S is the usual designation for a fine-thread drywall screw intended for light-gauge steel studs. Some variations, often labeled S-12 or with a drill-point tip, are made for slightly heavier steel. Check the packaging for the maximum gauge of steel the screw is rated for. If your framing is heavy structural steel, ask the supplier which fastener the system calls for rather than guessing.
How to tell coarse from fine
- Count the threads. Over the same length, a fine screw has noticeably more threads than a coarse one.
- Look at the spacing. Coarse threads are deep and far apart, while fine threads are shallow and tight.
- Read the box. Packaging usually says coarse or fine, or lists W or S.
- Check the point. Fine screws for metal often have a very sharp point or a small drill tip.
If you have loose screws with no label, place a known coarse and fine screw side by side and compare.
Choosing length
The screw should go through the board and well into the framing. A common rule of thumb is that the screw should penetrate wood framing by at least about 5/8 inch, and for metal studs it needs to pass through the steel. That is why 1-1/4 inch is common for single layers of 1/2-inch board, and longer screws are used for 5/8-inch board or double layers. Follow your board manufacturer’s or local building code’s fastening guidance if you need to be sure, especially for fire-rated assemblies.
What if you use the wrong one?
- Fine screws in wood: they can hold less well and may strip or spin more easily, so they are not generally recommended. Some pros use them successfully in certain conditions, but the standard guidance is coarse in wood.
- Coarse screws in metal studs: they can fail to grab the steel properly and may back out or spin.
- Wrong length: too short and the screw may not reach the framing, too long and it can poke through or hit wiring or pipes behind the board. Be careful of what is inside the wall. If you are drilling or screwing near a suspected electrical line, turn off power first, and call an electrician if you are unsure.
Installation tips
- Set the screw head just below the paper surface without tearing the paper, creating a small dimple for joint compound. A drywall screw gun with a depth-setting nosepiece helps.
- Do not overdrive. Torn paper reduces holding power. If it happens, drive another screw nearby.
- Keep screws a reasonable distance from board edges and follow the spacing recommended for your board.
- In damp rooms, see drywall for high humidity for board choices, and consider coated or corrosion-resistant screws.
Normal screws vs drywall screws
Drywall screws have a bugle-shaped head, a hardened steel body and a sharp point, built to hold thin board against framing. They are not the same as general wood screws, and they can be brittle under sideways load. For the full comparison, read wood screws vs drywall screws.