Which screw should I use in chipboard?
Which screw should I use in chipboard?
A twin-thread chipboard screw with an unthreaded shank under the head, so it pulls the joint together instead of bursting the board.
Chipboard is chips of wood in resin, so it is strong in compression across the face and weak everywhere else, particularly at an edge where a screw is trying to expand a hole in a material that cannot stretch. The twin thread exists because it removes material as it drives rather than compressing it outwards, and the unthreaded shank under the head exists for a different reason worth knowing generally: if a screw threads into the top piece as well as the bottom one, it jacks the two apart instead of clamping them together. That is why a clearance hole in the top piece makes almost any screwed joint tighter, in board or in timber. Moisture is chipboard's other weakness — a wetted board swells irreversibly and loses all screw holding.
The options, ranked
| Option | Good at | Bad at |
|---|---|---|
| Twin-thread chipboard screw | Drives fast, grips crushed particle board well, and the coarse thread bites into a weak core. | Still splits an edge without a pilot hole. |
| Screw with an unthreaded shank | The plain shank lets the top piece slide so the head clamps the joint tight. | Fully threaded screws are far more common on the shelf and hold the joint apart. |
| Confirmat screw | The flat-bottomed furniture screw used in flat-pack assembly; huge holding power in board edges. | Needs a stepped drill bit and precise hole placement. |
| Cam and dowel fittings | Designed for board edges, demountable, and the reason flat-pack furniture can be assembled at all. | Needs factory-accurate drilling. |
Technique that changes the outcome
- Pilot-drill edges, and use a clearance hole in the top piece
- Keep fixings 30 mm or more from the end of a board
- Do not overtighten; the head buries itself and the fixing is finished
- For a joint that will be taken apart, use knock-down fittings rather than screws
What goes wrong
- Fully threaded screws where you need the joint pulled together
- Re-using a stripped hole without a plug or a larger fixing
- Any exposure to water, which swells the board permanently
Compiled practical guidance rather than a published standard. Product formulations vary by brand and market, so read the label — and where the work is structural, electrical or gas, the regulations that apply where you are govern rather than anything here.
Other screw questions
| For | Use |
|---|---|
| Wood | A pilot hole matching the screw's core diameter in the lower piece and a clearance hole in the upper one — that is what makes a joint tight. |
| Decking | Stainless steel — 304 inland, 316 near the coast — or a screw specifically rated for modern treated timber, which eats ordinary zinc plating. |
| Masonry | A concrete screw into a precisely sized hole, or a plug and screw — and hollow block needs a different anchor entirely. |
| Plasterboard | Coarse-thread bugle-head drywall screws into timber studs, fine-thread into metal studs — and never use them for anything structural. |
| MDF | A straight-shank MDF screw with a parallel thread, always into a pilot hole — the edge splits without one. |
| Sheet metal | A self-drilling (Tek) screw with a drill point matched to the material thickness, or a self-tapping screw into a correctly sized pilot hole. |
| Plastic | A thread-forming screw designed for plastic, or a heat-set threaded insert where the joint will be undone more than once. |
| Roofing sheets | A hex-head screw with a bonded EPDM washer, driven until the washer just spreads — no further. |
| Brass hardware | Cut the thread with a steel screw of the same size first, wax the brass one, and use a driver that fits the slot exactly. |
Common questions
- Which screw should I use in chipboard?
- A twin-thread chipboard screw with an unthreaded shank under the head, so it pulls the joint together instead of bursting the board.
- What should I avoid?
- Fully threaded screws where you need the joint pulled together Re-using a stripped hole without a plug or a larger fixing Any exposure to water, which swells the board permanently
Related pages
- Which screw and pilot hole should I use for wood? A pilot hole matching the screw's core diameter in the lower piece and a clearance hole in the upper one — that is what makes a joint tight.
- Which screw should I use for decking? Stainless steel — 304 inland, 316 near the coast — or a screw specifically rated for modern treated timber, which eats ordinary zinc plating.
- Which screw should I use in masonry? A concrete screw into a precisely sized hole, or a plug and screw — and hollow block needs a different anchor entirely.
- Which screw should I use for plasterboard? Coarse-thread bugle-head drywall screws into timber studs, fine-thread into metal studs — and never use them for anything structural.
- Which screw should I use in MDF? A straight-shank MDF screw with a parallel thread, always into a pilot hole — the edge splits without one.
- Which screw should I use for sheet metal? A self-drilling (Tek) screw with a drill point matched to the material thickness, or a self-tapping screw into a correctly sized pilot hole.
- Which screw should I use in plastic? A thread-forming screw designed for plastic, or a heat-set threaded insert where the joint will be undone more than once.
- Which screw should I use for roofing sheets? A hex-head screw with a bonded EPDM washer, driven until the washer just spreads — no further.
- How do I drive brass screws without snapping them? Cut the thread with a steel screw of the same size first, wax the brass one, and use a driver that fits the slot exactly.
Sources
- Typical range compiled from manufacturer specifications — At One Place