Wafer Head (Modified Truss) Self-Drilling Screw

Overview

The wide, very low head sits almost flush, so board and trim can go over it. That makes wafer heads the standard screw for steel stud framing, track and metal lath.

Phillips, Pozi and square drives; #2 and #3 points for 0.5–2.5 mm steel.

Applications

Steel stud and track framing
Metal lath
Ductwork

Key features

Low head allows board over the fixing
Wide bearing face for thin sheet
Fast-start drill point
Bulk or boxed

Specifications

Typical values. Every dimension, hardness and coating is confirmed in writing with your quotation.

Wafer Head (Modified Truss) Self-Drilling Screw specifications
Diameter	ST4.2 (#8), ST4.8 (#10)
Length	13–50 mm
Material	C1022 steel, case hardened
Head	Modified truss / wafer
Drive	Phillips, Pozi, square
Drill point	#2, #3
Finish	Zinc plated
MOQ	20,000 pcs
HS code	7318.14 / 7318.12 (by type)

Buying guide

Applies to all self-drilling screws.

Match the drill point to the steel

Point #1 suits sheet up to 0.9 mm, #2 up to 2.8 mm, #3 up to 4.4 mm, #4 up to 5.25 mm and #5 up to 12.5 mm. The drill flute must clear the full material thickness before the thread engages, or the screw will jam and snap.

Choose a washer for weather-tight joints

Roofing and cladding screws take a bonded EPDM washer (14, 16 or 19 mm) under an indented hex washer head. The rubber seals the hole; the steel backing spreads the load so the sheet does not dimple.

Specify corrosion class, not just "zinc"

Electro-zinc gives roughly 72 h to white rust in salt spray. For exterior roofing ask for ceramic coating (500–1,000 h) or AS 3566 Class 3/4 coatings, and for coastal sites move to bi-metal stainless screws.

Ordering

Packing and delivery

Standard terms for this product. Tell us if your market needs something different.

PackingSmall boxes, buckets or 20–25 kg cartons on fumigated pallets; private label available.

Lead timeSamples in 7 days; production 25–35 days after deposit.

PaymentT/T 30 % deposit, 70 % against B/L copy, or L/C at sight.

ShippingFOB Shanghai or Ningbo, CFR or CIF to your port.

Questions about this product

What is the difference between self-drilling and self-tapping screws?

A self-tapping screw forms threads in a pre-drilled hole, while a self-drilling screw drills its own hole first using a drill-shaped point. Self-drilling screws save a step on metal-to-metal joints.

Which standards do your self-drilling screws follow?

We produce to DIN 7504 (K, M, N, P, O forms), ISO 15480–15483 and AS 3566.1/.2, and to customer drawings for non-standard lengths, heads or head marks.

What is your MOQ for self-drilling screws?

Standard sizes start at about 500 kg or 50,000 pieces per size. Mixed sizes can share one container, and stock items can ship in smaller lots.

Self-Drilling Screws