4mm Pozi Pan Head Chipboard Screws A2 Stainless
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- Stainless grade A2 (304)
- Drive Pozi
How to measure pozi pan head chipboard screws
| Dimension | Symbol | Value |
|---|---|---|
| Thread diameter (nominal) | d | 4.0 mm |
| Head diameter | dk | 7.42 to 8.00 mm |
| Head height | k | 2.68 to 2.92 mm |
| Pozi bit size | PZ | PZ2 |
| Lengths available (under the head, excluding head) | L | 13, 16, 20, 25, 30, 35, 40, 45, 50, 60, 70 mm |
4mm pozi pan head chipboard screws in A2 stainless steel. The rounded head sits on top of the surface, the thread runs the full length, and the pozi recess takes a PZ2 bit. The head sizes are based on DIN 7505, the old German standard for chipboard screws, which has been withdrawn.
A2 stainless steel resists corrosion, so these screws last in damp conditions as well as dry ones. There is no minimum order, so you can buy exactly what the job needs, and larger quantities get a lower price per screw.
Where pan head chipboard screws are used
A pan head has a flat underside that sits on top of whatever it is holding, with a low dome above it. That makes it a good choice for fixing metal brackets, plates and other fittings to board, and for any job where the head is meant to be seen.
The thread runs right up to the head and the point is sharp, so the screw cuts its own way into chipboard, MDF and similar board. Most of the time you can drive it without a pilot hole. Near an edge or corner a small pilot hole is still worth drilling, to stop the board splitting.
A pozi recess has extra contact points, so the bit is less likely to slip out under load than with a Phillips head.
The head stays proud, so there is no countersinking to do. If you want it level with the surface, the 4mm pozi countersunk chipboard screws and 4mm Torx countersunk chipboard screws have a flat head instead.
For solid timber rather than board, the No.8 (4mm) pozi round head wood screws are the better fit. They are partially threaded, so the plain shank under the head can pull one piece of timber tight against another.
Sizes and lengths for the 4mm
4mm is the nominal thread diameter, and No.8 is the nearest trade gauge. The sizes either side are 3.5mm (No.6) and 4.5mm (No.9).
Length is measured under the head, from the flat underside to the tip. The head height is not included, so a 30mm screw goes 30mm into the board and the head sits on top. You can choose from 11 lengths, 13mm to 70mm.
The head is 7.42 to 8.00mm across and 2.68 to 2.92mm high. If you are fixing a bracket or plate, add its thickness to the length you need, and keep the point short of the far face of the board.
A2 or A4 for chipboard work
A2, also called 304 or 18/8, is the standard stainless for fixings. It suits most indoor jobs and general outdoor use. For board fittings that stay damp or humid, A4 is worth considering.
Our guides to A2 stainless steel and A4 stainless steel cover the differences in more detail.
Pan head chipboard screw questions
How big is a 4mm pan head chipboard screw?
A 4mm chipboard screw is 4mm across the thread, which is close to a No.8 gauge. The pan head is 7.42 to 8.00mm across and 2.68 to 2.92mm high, and the pozi recess takes a PZ2 bit.
What bit fits a pozi pan head chipboard screw?
The 4mm takes a PZ2 pozidriv bit. Across this range the 3mm screw takes a PZ1, and the 3.5mm to 5mm sizes all take a PZ2.
Do pan head chipboard screws need a pilot hole?
Usually not, because the sharp point and full thread cut into chipboard and MDF on their own. Near a board edge or corner, a small pilot hole first lowers the risk of splitting.
Should I use a pan head or a countersunk chipboard screw?
Choose a pan head when the head stays on show or has to clamp a metal fitting, because the flat underside bears down on the fitting. Choose a countersunk head when the screw has to finish flush with the surface.
How do you measure a pan head chipboard screw?
Measure length from the flat underside of the head to the tip, so the head is not counted. The measuring guide above the table shows where to place the rule. For thickness, put a caliper across the outside of the thread, where a 4mm screw reads 4mm or a touch under.