Published July 26th 2023

How To Work An Ovolo In Stone

A classical segmental ovolo mould
A classical segmental ovolo mould

The ovolo is a classical stone moulding consisting of a quarter circle, radius a-b, bounded by two fillets c and d. The line formed by a-d being perpendicular to that formed by a-c.


Steps For Working An Ovolo Mould In Stone

Applying The Template To The Stone

Initial stage of working an ovolo in stone
Marking the mould on the stone

The process of working an ovolo  mould begins by marking the template onto the parallel joints of the stone using a scriber. Templates for stone are traditionally made from zinc sheeting.


Working The Initial Chamfer

Working the initial chamfer on the stone
Working the initial chamfer on the stone

The next step is to scribe a large chamfer on the stone. Note from the picture that the chamfer is marked on such that it touches two of the outer edges of the mould to be worked. Working to two points of the mould like this maximises efficiency.


Working The Fillets

Working the fillets of the ovolo mould
Working of the fillets of the ovolo mould

With the large chamfer finished, the two fillets are worked. As with all stages of working stone, the fillets are checked with a straight edge for trueness.


Working Further Chamfers

Working a series of chamfers on the round of the ovolo mould
Working a series of chamfers on the round of the ovolo mould

Once the fillets are worked the curve of the mould is defined further with smaller chamfers. The marking of the chamfers on the stone is done with a sliding bevel to ensure they are the same angle and parallel.


Finishing The Ovolo Mould

The finished ovolo mould worked in stone
The finished ovolo mould worked in stone

Following on from the previous stage, the curve of the mould is refined by working further chamfers on the stone with each being smaller than the last until a true curve is produced. The final stage is to tool the curve over to remove any flat spots with a bolster and dummy.

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