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Proportional reduction of mouldings
By Greg Cheetham
Original given mould
New mould proportionally reduced
Original given mould
X
Y
Drawer out the original mould on an X,Y grid as shown
Original given mould
Required new height of mould
Required new width of mould
Drawer in line A across extremities to establish line for proportional reduction.
Then
Line B parallel to Line A to set a new height and width as required for new height and widths
Line A
Line B
Original given mould
Use a compass from XY intersection to transfer points 1 an 2 to X, Y line as shown.
1 2X
Y
2
1
Project new points 1 and 2 as indicated with arrowed lines
Original given mould
Drawer diagonal as indicated
Project original height and width lines to diagonal and then project down or across as required
Original given mould
Original given mould
Required new height of mould
Required new width of mould
Firm in the outline of the proportionally reduced moulding
Original given mould
Required new height of mould
Required new width of mould
New mould proportionally reduced
