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A short introductory presentation on how to produce an ovolo mould on sandstone using traditional tools and techniques
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Stonemasonry Department 2012
Cutting an Ovolo MouldIntroduction for Stonemasons
Mould Recognition
FACE OF STONE
FILLET
OVOLO
FILLETTOP BED OF
STONEAn ovolo moulding consists of a
number of elements which can be
seen in the diagram. It is essential
that you are able to readily identify
each element so that you can
follow the correct procedures for
setting out and cutting an ovolo
mould.
Roman Mould Development
Begin by marking the total width of the
mould on the base line to form points A and B.
A B140mm
Roman Mould Development
Begin by marking the total width of the
mould on the base line to form points A and B.
A B
Strike lines at 90° to the base line which run through points A
and B
140mm
140m
m
Roman Mould Development
Begin by marking the total width of the
mould on the base line to form points A and B.
A B
Strike lines at 90° to the base line which run through points A
and B
140mm
Mark the total height of the mould from
point A and strike a line to form a perfect
square and form points C and D
140m
mC D
Roman Mould Development
Begin by marking the total width of the
mould on the base line to form points A and B.
Strike lines at 90° to the base line which run through points A
and B
20mm
Mark the total height of the mould from
point A and strike a line to form a perfect
square and form points C and D
Construct the grid for the mould using the
appropriate sizes
60mm
20m
m60
mm
Roman Mould Development
Begin by marking the total width of the
mould on the base line to form points A and B.
Strike lines at 90° to the base line which run through points A
and B
Mark the total height of the mould from
point A and strike a line to form a perfect
square and form points C and D
Construct the grid for the mould using the
appropriate sizes
Using centre E strike a curve hitting points F
and G to form the cavetto.
EG
F
Roman Mould Development
At this stage the mould is complete and you should darken the
appropriate lines to better define the mould. If you are
producing a template you should complete
the template by including all relevant information eg mould
name, type of template, your name, top bed and joint etc.
A STUDENTOVOLO
JOINT TEMPLATE
TOP BED
FACE
Cutting an OvoloHold template to top bed and face
of stone, making sure to align it properly by holding a straight edge
against the aligned face and bringing the template to meet the
straight edge.
Mark template to both joints and scribe
across the top bed and face to join the
profiles.
Cut a splay to remove the waste stone. The splay should be 2-4mm above any cutting
lines.
Run the mould through by setting in along the
arrises, teething down and chiselling. The mould should be checked for
straight between the joints and a reverse template can be used to check for
accuracy.
Set in the mould on both joints and check accuracy with joint and
reverse templates.
Join the fillets along the length
of the mould.
Set in the fillets at the top and bottom of the mould, checking with a sinking
square that they are square and at the correct depth.
Marking a Mitre
There are two common methods of marking a mitre line; using mitre blocks and
using two steel squares. The mitre block method is often easier but a stonemason is
more likely to carry the squares in their toolkit. Your course tutor will demonstrate
each method in the workshop.
A mitre is the term used to describe the arris formed when adjacent mouldings
intersect. There are both external and internal mitres.
EXTERNAL MITRE MITRE BLOCKS STEEL SQUARES
Cutting an Ovolo to an Ashlar StopBegin by marking an external mitre line on the existing mould. The top point of this line is determined by applying the joint template to the back of the stone and squaring, from the face, to the top of the
fillet
Mark a splay to remove the
wastage from the return
mould.
Run the mould through by setting in along the
arrises, teething down and chiselling. The mould should be checked for
straight between the joints and a reverse template can be used to check for
accuracy.
Set in the mould at the mitre and close to the ashlar stop
and check accuracy with reverse
template.
Join the fillets along the length
of the mould.
Set in the fillets at the top and bottom of the mould, checking with a sinking
square that they are square and at the correct depth.
Developed by The Stonemasonry DepartmentCity of Glasgow College
2012