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Square to Rounds Pattern Only

Ventilation Ducting  | Rectangular Ductwork |  Square to Rounds Pattern Only

Ductwork Transistions

Square to Round Patterns

Note that this product is for a pattern only. The pattern itself may be formed by the purchaser, or it can be used a template to produce additional square to rounds. We will cut out the square to round required on a CNC cutting machine but it will be supplied as a flat sheet steel pattern in two halves (square to rounds are commonly made in two halves). The square to round will not be formed or fixed by us. It is assumed that the purchaser is familiar with the method used to form the piece. If you require the finished piece, i.e. fully formed and fixed please see:

Square to rounds.

Ductwork square to rounds, as the name suggests, convert square or rectangular ductwork to round wherever such a transition is required. This may be to connect rectangular ductwork to ventilation equipment designed for a circular connection, or to change the duct shape to pass through a confined space. In confined areas such as ceiling voids (the space between the suspended and structural ceiling of a building) it's common to see ductwork runs comprised of both rectangular and round spiral duct - the main duct and branches are rectangular as the equivalent sized round duct may not fit into the ceiling void. Square to rounds provide the means to make this transition.

There are many possible shapes and sizes of square to rounds. Most are symmetrical but some may be offset to one side or two sides. They can also be angled, effectively producing a combined elbow and transition in one. We are able to manufacture any square to round required if a clearly dimensioned drawing is supplied to us. Otherwise it is possible to order them online but with limitations to the size and general design (symmetrical and offset to one side - one side is flat - can be defined on the website). Square to rounds offset to two sides and/or with a larger offset will require a drawing.

If you need to calculate the size of the square end of a transition piece relative to the round end, or vice-versa. Please use the link below:

How to calculate square to round transition sizes..

Please use the drop-down menu below to select the width of the square to round required as depicted in the drawing to the right. Depth, diameter, and style can be selected on the following pages.


Ductwork Square to Rounds
75mm Width 100mm Width
150mm Width 200mm Width
250mm Width 300mm Width
350mm Width 400mm Width
450mm Width 500mm Width
550mm Width 600mm Width
650mm Width 700mm Width
750mm Width 800mm Width
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