DN400 | Twin Chainwinder

When to Specify the DN400

The DN400 Twin Chainwinder is the correct specification when a single chainwinder reaches the limits of its application range. Four scenarios determine the specification decision:

Large awning windows where a single chain cannot distribute load evenly across the sash width. On wide or heavy awning windows, a single-point chain connection creates uneven sash loading — the window opens and closes unevenly, stressing the hinge system and creating operational issues over time. The DN400’s twin chain configuration distributes the operating load across two attachment points, providing balanced sash movement and protecting the hinge framing from asymmetric stress.

Sash weights approaching or exceeding standard single winder thresholds. When used in conjunction with Doric’s Heavy-Duty Stainless Steel stays or a continuous hinge framing system, the DN400 will easily operate awning windows with sash weights up to and beyond 100kg. For commercial buildings, institutional facilities, and premium residential projects where architects and builders are specifying large-format glazing in awning window openings, this is the specification that makes those windows operable without mechanical failure.

Commercial and institutional applications — schools, hospitals, aged care facilities, office buildings, and industrial environments — where large awning ventilation windows require a heavy duty commercial chainwinder that performs reliably across high-cycle use over the building’s service life.

Direct replacement programs on existing large awning window installations where the original twin chainwinder has reached the end of service life and a like-for-like replacement is required without frame modification.

For standard residential awning windows where a twin chain is not required, the DS1 or DS2 single chainwinder is the correct specification. 

View DS1 Chainwinder | View DS2 Chainwinder

Product Configurations — DN400, DN402

The DN400 Twin Chainwinder is available in three configurations. Selecting the correct configuration before specifying is the primary ordering decision:

DN400 — Keyed Twin Chainwinder (Kids Don’t Fly / NCC) Full key lockable configuration. Available with either DS94 (6 Disc Wafer Cylinder) or DS187 (C4 Pin Cylinder). The DS94 can be keyed alike to Doric’s DS126 cylinder, allowing the DN400 to share a key with DS1 Chainwinders and other compatible Doric window hardware across a development — a single key for all window hardware on a mixed single and twin chainwinder schedule.

DN402 — Non-Keyed Twin Chainwinder Non-keyed configuration for applications where security lockability is not a project requirement. Suited to commercial and institutional settings where window operation is managed by facilities teams, or internal large awning windows where the door hardware schedule manages building security.

On large awning windows, restriction compliance carries a higher consequence than on a standard residential opening. A large-format window in a multi-storey setting represents a greater fall risk — and a restriction that is incorrectly set or inconsistently applied across a program is a certifier problem, not just an installation variance.

NCC Compliance & Child Safety — DN400

The DN400 addresses this directly. Restriction is set at the factory before the unit leaves Doric. Across a large commercial program or multi-storey residential development with dozens of restricted large awning openings, this removes an entire class of compliance risk.

Twin Chain Operation — Why It Matters

The defining specification difference between the DN400 and a single chainwinder is the twin chain mechanism. Understanding why this matters is central to specifying it correctly.

On a large awning window, the sash is effectively a lever — the wider the sash and the heavier the glazing, the greater the torque load placed on a single-point chain connection at the winder. A single chain resists this load from one point, creating a rotational force that works against smooth, even opening and closing. Over time and across thousands of cycles, this asymmetric loading accelerates wear on both the winder mechanism and the hinge system.

The DN400’s twin chain configuration distributes the operating load symmetrically across the sash width. Both chains extend and retract in unison from a single lever operation — the user operates one fold-down lever, both chains move together, and the sash opens and closes with balanced, even pressure across its full width. The result is smooth, even operation across sash weights and widths that exceed single chainwinder capacity — windows where a single chainwinder would require significantly more effort, create uneven movement, or fail prematurely under repeated load.

Chain pitching — the mechanical advantage built into the DN400’s twin chain drive — provides greater control and reduced operating effort on large sash openings compared to a standard single chain winder. This is why the DN400 is specified for large awning applications where two separate single winders would create independent chain tension variance and inconsistent sash movement. The DN400 operates as a single, synchronised unit — one lever, two chains, one balanced sash movement.

Material & Construction

The DN400 is built on a die cast zinc body — a different material platform from Doric’s Polesium™-based DS1 and DS2 chainwinders, and the correct choice for a twin chainwinder operating under the higher structural loads associated with large sash windows.

Die cast zinc provides the dimensional rigidity and structural strength the DN400’s twin chain mechanism requires to operate reliably under load. Where the DS1 and DS2 suit standard residential awning windows, the DN400’s zinc construction is engineered specifically for the heavier-duty application it is designed for — a material specification decision that reflects the product’s application range, not a cost consideration.

Stainless steel chain standard — corrosion resistant, dimensionally stable under load, and appropriate for external window applications across all Australian climate conditions, including coastal and tropical environments where salt air and humidity accelerate hardware degradation.

Neutral Salt and Spray tested in accordance with AS2331.3.1 — confirming corrosion performance against Australian Standards for external hardware applications.

Cylinder Options & Keyed Alike

For keyed configurations (DN400 and DN404), two cylinder options are available:

DS94 — 6 Disc Wafer Cylinder: Can be keyed alike to the DS126 cylinder used in the DS1 Chainwinder, enabling DN400 twin chainwinders to share a key with DS1 single chainwinders across a project. For builders and strata managers specifying a development with a mix of standard and large awning windows, the DS94’s keyed alike capability eliminates key proliferation across a mixed single and twin chainwinder hardware schedule — one key for all compatible Doric window hardware on the project.

DS187 — C4 Pin Cylinder: For projects using Doric’s C4 pin keying system across door and window hardware.

Installation — Chain Secure System

The DN400 uses Doric’s Chain Secure system — a removable chain connection from the sash plate that simplifies both installation and ongoing maintenance. The chain can be detached from the sash plate without tools, allowing the winder body to be installed independently of the chain connection and the sash to be cleaned without the chain obstructing access.

For installers on commercial programs with high window counts, Chain Secure reduces per-window installation time and simplifies the installation sequence — the winder body is fixed to the frame, the chain is then connected to the sash plate as a separate step without requiring the sash to be held in position throughout.

The DN400 body is 484mm in length with a 499mm total installed dimension — confirm these dimensions against the window frame profile and reveal depth before specifying on projects where extrusion width or reveal depth is a constraint.

What makes the DN400 a twin chainwinder and when is it required? 

The DN400 uses two chains operated by a single lever to distribute load symmetrically across wide or heavy awning window sashes. It is required when a single chainwinder cannot manage the sash weight or width without creating uneven opening, excessive operating effort, or premature wear on the hinge system. It is the correct specification for large awning windows in residential and commercial applications.

What is the difference between DN400, DN402, and DN404? 

DN400 is the keyed twin chainwinder with DS94 or DS187 cylinder options. DN402 is the non-keyed variant with no cylinder. DN404 is factory pre-restricted for NCC and Kids Don’t Fly compliance, available with either cylinder option. Specify DN404 where NCC restriction on large awning windows is a project requirement — factory pre-restriction ensures consistent compliance across every unit without site-based setup.

When should I specify the DN400 over two separate DS1 chainwinders? 

The DN400 should be specified when the window sash requires synchronised twin chain operation — a single lever controlling two chains simultaneously for balanced, even sash movement across the full sash width. Two separate DS1 chainwinders would operate independently, creating chain tension variance and inconsistent sash movement. The DN400 functions as a single, synchronised unit; two separate single winders do not.

What sash weight can the DN400 handle? The DN400 does not have a published weight or load rating. When used with Doric’s Heavy-Duty Stainless Steel stays or a continuous hinge framing system, the DN400 will easily operate sash weights up to and beyond 100kg. Confirm the stay or hinge system specification with Doric for specific project load requirements.

Why is the DN400 built from die-cast zinc rather than Polesium™? 

Die-cast zinc provides the structural rigidity required for a twin chain mechanism operating under the higher loads of large awning sashes. Polesium™ is the correct material for single chainwinders in standard residential applications; die-cast zinc is the correct specification for the DN400’s heavy-duty application environment. This is a material specification decision that reflects the product’s application range.

Can the DN400 be keyed alike to DS1 Chainwinders on the same project? 

Yes. The DS94 6 Disc Wafer Cylinder used in the DN400 and DN404 can be keyed alike to the DS126 cylinder used in the DS1 Chainwinder. This allows a single key to operate both standard and twin chainwinders across a development with a mixed window hardware schedule.

Is the DN404 factory pre-restricted, or can restrictions be set on site? 

The DN404 is factory pre-restricted — restriction is set before the unit leaves Doric, ensuring consistent NCC compliance across every unit on a project. For projects requiring selective restriction, DN404 can be specified on restricted openings alongside DN400 or DN402 on unrestricted openings within the same hardware schedule.

What are the DN400’s body and installed dimensions? 

The DN400 body is 484mm in length with a total installed dimension of 499mm. Confirm these against your window frame profile and reveal depth before specifying.

Is the DN400 NCC compliant for child safety on large windows? 

NCC compliance is achieved through the DN404 pre-restricted variant. The DN400 and DN402 are not pre-restricted. Specify the DN404 for any large awning window opening where NCC window restriction requirements apply.

What corrosion testing has the DN400 undergone? 

The DN400 has passed Neutral Salt and Spray testing in accordance with AS2331.3.1, confirming corrosion performance against Australian Standards for external hardware applications.