Screws look similar at a glance, yet the thread, head, and tip are shaped for specific materials. Using the right type helps parts hold together and reduces splitting or stripping. This chart compares the common kinds and the jobs they usually do.
Screw Comparison Chart
| Screw | Material | Thread and tip | Typical job |
|---|---|---|---|
| Wood screw | Solid wood | Tapered, partly smooth shank | Furniture and general carpentry |
| Construction screw | Lumber | Sharp, deep thread | Framing and outdoor builds |
| Drywall screw | Wallboard to studs | Fine or coarse thread, bugle head | Hanging wallboard |
| Machine screw | Metal with matching threads | Uniform thread, blunt end | Fixing parts with nuts |
| Sheet metal screw | Thin metal | Sharp thread along full length | Ducts and panels |
| Self-drilling screw | Metal | Drill-like tip | Metal framing |
| Lag screw | Heavy timber | Large hex head | Heavy connections |
Head Shapes in Brief
- Flat heads sit level with the surface once countersunk.
- Pan or round heads sit on top and spread the load.
- Hex heads take a wrench or socket for more turning force.
Drive Types
The recess decides which driver bit fits. Cross-shaped, six-point, and square recesses each resist slipping differently, and the packaging usually names the correct bit. A bit that fits snugly lowers the chance of damaging the head.
Outdoor and Damp Locations
Coatings and metals vary in how well they resist rust. Read the label to confirm a screw is meant for outdoor or damp use. For decks, railings, and anything structural, follow the maker’s guide, check local building rules, and ask a qualified professional.
A few small habits improve nearly every screw job. Drive the screw in a steady motion rather than in bursts, and stop as soon as the head is set. Overdriving can strip the hole or snap the screw. Keep the driver straight, and press firmly to prevent the bit from slipping out. Using lubricant such as wax on threads can help in hard wood, if the maker permits. Store screws in labeled containers by type and length so you can reach for the right one.
Two more details are worth knowing. First, some screws are designed to be driven without a pilot hole, while others work best with one, so the packaging is the best guide. Second, thread length varies. Fully threaded screws grip along their whole length, while partly threaded screws pull two boards together because the smooth shank slides through the top piece. Choosing between them depends on what the joint must do.
When removing old screws, use a bit that fits the damaged head and apply steady inward pressure.
FAQ
Do I always need a pilot hole?
Not always, but it often helps in hardwood or near board ends. The right hole size depends on the screw, so check the maker’s guide.
Can I use drywall screws for everything?
They are brittle and made for wallboard. For load-bearing work, use fasteners intended for it.
The Short Version
Match the screw to the material, the load, and the location. Use a snug bit, drill pilot holes where helpful, and treat structural jobs with extra care.