The screw on the gun is not “a drywall screw.” It is a thread, a point, and a standard. Fine thread into wood still bites; coarse thread into 25-ga steel walks or strips. That is how a hang fails before the taper opens a box.
This page restates public class language from ASTM C1002 (self-piercing tapping screws for gypsum panel products) and ASTM C954 (screws for heavier steel), plus Gypsum Association fastener notes and manufacturer data (Grabber and peers). It is not a SKU catalog and not a substitute for the listed fire design, which can name length and spacing that beat the general C840 / GA-216 table. See how to hang drywall for the hang pattern those screws sit in.
ASTM C1002 — the self-piercing family
C1002 covers steel self-piercing tapping screws for gypsum (and metal plaster base) into wood and into cold-formed steel thinner than 0.033 inch (0.84 mm), and for gypsum into gypsum. Four thread types in the spec:
| Type | Thread (spec language) | What it fastens |
|---|---|---|
| S | Fine-thread | Gypsum to light-gauge steel |
| W | Coarse-thread | Gypsum to wood |
| G | Coarse-pitch, high-thread | Gypsum to gypsum (laminating) |
| A | Coarse-pitch tapping | Metal plaster base to wood or steel |
Bugle head is the interior gypsum default so the head dimples the face paper. Wafer / pan / trim heads are other jobs (lath, steel-to-steel, beads). Corrosion-resistant coating that does not kill compound adhesion is in the spec — do not use a rusty deck screw and hope the mud sticks.
C1002 is the light-gauge and wood document. Once the steel is 0.033 inch and thicker, you are in ASTM C954 territory: self-drilling points, commonly called Type S-12 in the trailer. C954 also runs up through thicker structural CFS. Interior 25-ga / 18-mil drywall stud is C1002 Type S. Structural 33-mil and the exterior backup on the same job often are not. See exterior CFS vs interior light-gauge.
Type S — fine thread, light-gauge steel
Pierces and taps steel that is too thin to want a drill point. Fine thread so the thin flange has enough engaged threads to hold. This is the commercial metal-stud hang screw: interior C645 / AISI S220 drywall stud, shaft-stud face layers when the member is still in the C1002 thickness range, hat channel, resilient channel.
Do not run Type W coarse into that flange. Gypsum Association public fastener notes are blunt: a Type S may be used into wood; a Type W into steel is the wrong recommendation. The coarse thread does not find enough steel.
Collated Type S coils earn their keep on long commercial runs. They do not excuse missing a stud. Depth-sensitive guns exist so you dimple instead of punching paper — production tools, Tools.
Type W — coarse thread, wood
Coarse thread into dimensional lumber, trusses, and wood furring. This is residential production and the wood-frame rooms on a mixed-use job.
Length has to put the required thread into the wood. Manufacturer and gypsum application notes commonly cite at least 5/8 inch penetration into wood for drywall screws; the listed fire design may want a named length (for example a 1-inch minimum in a given UL wall). Do not invent a length from another job.
Edge distance still at least 3/8 inch from paper edges and ends — same hang rule as steel.
Type G — laminating, board to board
Type G is the laminating screw: coarse-pitch, high thread, made to bite gypsum core, not a stud. Used when a face layer is laminated to a base layer (adhesive plus mechanical, or the mechanical part of a laminated system).
Laminating adhesive is a different product on the same takeoff — the gypsum mill’s laminating adhesive, applied to that mill’s pattern. Screws without adhesive, or adhesive without the fastener schedule the design named, are not a silent “double hang.” Base-layer spacing often opens up when the face layer is fastened through to framing; a laminated face that is not driven to the stud follows the laminating schedule, not the single-layer wall table. Rated multi-layer walls are the wrong place to improvise. Pull the UL / GA-600 design.
Type G is not a substitute for Type S into steel or Type W into wood. If the face layer has to hit the stud, you want the thread that matches the stud, at the length that reaches it through both layers.
Type A, briefly
Type A in C1002 is the plaster-base / lath screw. If the wall-and-ceiling package includes metal lath, that is the class. It is not the interior gypsum bugle on a Level 4 corridor.
Length, layers, and the fire design
Public application language and listed designs talk in named lengths, not “whatever is on the coil.” Pattern the trailer sees on multi-layer steel walls (always confirm the design):
- Base layer: often a 1-inch Type S (or S-12) class screw
- Face layer: often 1-5/8 inch so it reaches the steel through the base layer
Wood multi-layer and three-layer shaft faces change those numbers. The listed design wins. AWCI and UL commentary on fire-resistive screws is the same warning: a shorter screw than the design named is how an inspector challenges the wall.
Single-layer spacing (screws, no adhesive) is in the hang guide: walls 16 inches o.c. at 16-inch framing, 12 inches at 24-inch framing, ceilings 12 inches — then tighten to the fire design, which often wants 12 inches on walls anyway.
Dimple, do not punch. Head just below the face paper. Torn paper is a fastener that photographs or blows out.
What belongs on which truck
Residential production. Type W, often collated. Type S only if that house or garage wall is actually steel. Laminating screws show up on overlays, curved work, and the occasional double-layer garage separation — not in the everyday 1/2-inch coil.
Commercial wall and ceiling. Type S is the default hang screw on interior stud. S-12 / C954 on heavier steel, shaftwall faces when the member needs it, and exterior CFS. Type W for wood blocking, nailers, and the wood-frame rooms on the same floor. Type G plus laminating adhesive where the design is a laminated face. Metal-to-metal framing screws are a different SKU — they frame the wall; they do not hang the board. ClarkDietrich and every steel house sell the framing screws; Grabber sits in both Fasteners and Tools.
Do not hang a 1-hour corridor with a wood-screw coil because that is what was on the truck.
Related directory
Fasteners, Grabber, Tools, Manufacturers. Steel thickness that drives S vs S-12: Steel stud / framing, Exterior cold-formed framing.
FAQ
Can I use Type S into wood?
Gypsum Association public notes allow Type S into wood. Production shops still stock Type W for wood because the coarse thread is what that gun and that coil are set up for. Do not treat that permission as a reason to run one coil on every substrate.
Can I use Type W into steel?
Not as the recommended hang into light-gauge drywall stud. Fine thread (Type S) is the C1002 class for that steel. Coarse thread strips or never really bites 18-mil flange.
When do I need S-12 / C954?
When the steel is 0.033 inch and thicker — 20-ga structural, most exterior CFS, many 18-ga and 16-ga members. Self-drilling point, not a C1002 piercing point. If the screw spins on the flange, you likely brought the wrong point.
Is a laminating screw the same as a longer Type S?
No. Type G is made to hold gypsum to gypsum. A longer Type S is made to reach steel through two layers. The listed design says which one you are looking at.
Do collated screws change the spec?
No. Collation is packaging. The screw still has to be the C1002 or C954 type, length, and head the hang and the fire design require.