Chipboard screws buying guide: diameter then length

Updated: 22 October 2026

You are fitting a cupboard carcass, a loft panel or a batten onto chipboard, and the amazon.co.uk grid mixes 30 mm furniture screws with 60 mm boxes and mixed tubs.

You are fitting a cupboard carcass, a loft panel or a batten onto chipboard, and the amazon.co.uk grid mixes 30 mm furniture screws with 60 mm boxes and mixed tubs. This chipboard screws buying guide keeps one order: diameter, then length, then thread, then drive, then finish. The ten boxes, with GBP prices and the conflicts on their cards, sit on the chipboard screws comparison. Figures here are those listings and the public UK sources named below, not a live checkout and not a laboratory pull-out test. A qualifying purchase can earn a commission at no extra cost to you. By the end you should know which decision comes next, and which sentence on a listing to leave unsettled.

Our top picks

Badge	Product	Size	Thread	Drive	Note	Price	Offer
Best overall	fischer fischer Power-Fast II 4.0 x 40 mm	4.0 x 40 mm	Fully threaded	Phillips	7.9	about £19.85	View offer
	TIMCO TIMCO Solo 4.0 x 50 mm	4.0 x 50 mm	Fully threaded	PZ in the title; Phillips in the drive field	9.0	about £5.40	View offer
Alternative	Ulti-Mate Ulti-Mate floorboard 4.2 x 50 mm	4.2 x 50 mm	Partial, disputed	Phillips and square	7.6	about £9.99	View offer

Best overall

fischer fischer Power-Fast II 4.0 x 40 mm

7.9/10about £19.85

View offer

Rank 2

TIMCO TIMCO Solo 4.0 x 50 mm

9.0/10about £5.40

View offer

Alternative

Ulti-Mate Ulti-Mate floorboard 4.2 x 50 mm

7.6/10about £9.99

View offer

On this page

1.Start with the job and one size
2.Length, then full thread or part thread
3.Drive and finish
4.Read the title against the spec block

Start with the job and one size

A chipboard screw, in the Screwfix buying guide, is the countersunk screw whose coarse thread runs to the head. For one indoor box, the usual single size in this set is 4.0 mm, the old No. 8. That is the TIMCO Solo 4.0 x 50 mm, 200 pieces at about £5.40, and the band of the fischer 4.0 x 40 mm box of 1,200 at about £19.85. You are choosing a diameter the board and the bit can live with. An assortment is a workshop tub, not one specified fixing. Gorffy, ANVINKU and Ulti-Mate’s 1,600-piece box do not print one diameter you can hand to a drawing. If the drawing says 4.0 x 50 mm, buy that size. Who each row is for is on best chipboard screws.

Length, then full thread or part thread

A part thread, or a flooring screw with a smoother shank and an upper thread, is the clamp. If the thread grips the top board as well, it can hold the joint open. Ulti-Mate’s 4.2 x 50 mm floorboard screw says partially threaded in the field, and one UK review says the thread runs to the head. You cannot call that box both patterns.

Testsieger

fischer fischer Power-Fast II 4.0 x 40 mm

7.9/10about £19.85

View offer

Drive and finish

PZ2 covers most 3.5–5.0 mm timber screws. Pozidriv is the cross with the small tick marks between the arms. Phillips is a plain cross, and PH2 is the bit many household drivers already hold. Shop4Fasteners states that a Phillips bit in a Pozidriv screw slips and damages the head. The full split, including Torx, is on the Pozidriv vs Torx screws page. Read the recess the listing states, and buy the matching bit if the box does not include one you can trust. The TOPYWMSP bullets claim a 72-hour salt-spray test and a never-rust guarantee. That is the seller’s wording, not a service life. If the job is outdoors in the weather, leave this set.

Read the title against the spec block

A star line is not a pull-out test, and a tidy title is not the spec block. On the TIMCO Solo the title says PZ. The drive-system field says Phillips and the head-type field says Hex. The maker page for 40050SOLOC says PZ2, double countersunk, fully threaded, zinc and yellow, carbon steel. Open one screw and match the bit to the recess you can see. Two UK review texts also name 15 mm or 100 mm rather than 4.0 x 50 mm. Call a professional when the floor is a warranty or building-control deck, when you cannot see what is under the board, or when the joint needs a declared structural value the listing does not have. A SENCO article cites EN 14592 for that screw only. ETA-19/0175 covers fischer Power-Fast II from 3.0 mm to 6.0 mm, not an unbranded assortment.

Common questions

What should I decide first: diameter, length, thread, drive or finish?

Decide the job, then the diameter, then the length, then whether you need a full thread or a clamp, then the drive, then the finish. A 4.0 mm indoor box is the usual carcass choice in this set. A 3.5 x 30 mm screw is light furniture. Finish comes last, because a yellow coating does not fix a recess stated twice.

Is a thread that runs to the head the chipboard-screw pattern?

Screwfix defines a chipboard screw as the one whose thread extends to the head, and uses that point to separate it from a coach screw. A full thread grips both pieces of chipboard. A part thread clamps a board down onto a joist. If the listing says both, look at one screw from the parcel.

When do I want a part thread instead of a full thread?

Use a part thread, or a shank that can slide, when you are pulling a board down onto a joist and you do not want the thread to grip the top piece. A full thread is the better grip when both pieces are chipboard. In a floor, a full thread can hold the board off the joist.

Is yellow zinc in this set an outdoor finish?

Yellow, blue and bright zinc here are plated steel, and none of the ten boxes is A2 or A4. The TIMCO Solo maker page for code 40050SOLOC gives corrosion rating 1, for clean, dry, low humidity. That is not the class 2 rating on TIMCO’s separate C2 screw. A 72-hour salt-spray bullet is not approval for a fence, a deck or the coast.

Why does a box title sometimes disagree with its own spec block?

Sellers paste more than one catalogue row onto one Amazon page. The TIMCO title says PZ while the drive field says Phillips. The fischer 5.0 x 60 mm title says TX and full thread while a bullet says PZ and part thread. Measure one screw before you drive a room of them.

Is an assortment a substitute for one specified size?

Only when the job itself is mixed and short, such as a few hinge blocks and a light batten. Gorffy, ANVINKU and the 1,600-piece Ulti-Mate tub do not print one diameter. If you need 4.0 x 50 mm or 5.0 x 60 mm, buy that size. UK reviews already describe a Gorffy box arriving mixed.

Screws for chipboard flooring