Stonemasonry Department 2012

Cutting a Cavetto MouldIntroduction for Stonemasons

Mould Recognition

FACE OF STONE

FILLET

CAVETTO

FILLET

TOP BED OF STONE

A cavetto 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 a cavetto

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 20mm

20m

m20

mm

60m

m

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.

 

E

G

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 STUDENTCAVETTO

JOINT TEMPLATE

TOP BED

FACE

Cutting a SplayMark splay lines on

the joints and scribe lines across the face and top bed to join the

splays. 

Make the lines safe using a half inch chisel. Always work away from the line and toward the

centre of the splay.

 

Pitch the joints to the working lines. You may

wish to support your stone at an angle so that your

splay is sitting level.

 

Using marginal drafts, set in the joints, top and bottom of the

splay.

 

Rough out the centre section

using mel-point and teeth tool.

 

Chisel centre section to flat. Check for flat across

the length, width and diagonals of the splay.

 

If splay is to be seen, polish to fine

finish.

 

Cutting a CavettoHold 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.

 

Cutting a Cavetto Video

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 a Return MouldBegin 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.

 

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 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