As all the vertical and squaring settings have so far been taken from the side panel wall, it does not necessarily follow that the adjacent wall will be parallel to the side panel. To check this place a spirit level onto the side of the side panel ensuring that it is vertical, and at the same time measure across from its outside edge to the adjoining wall at the bottom, middle, and top to compare for any differences in width. If all the measurements are equal, then the adjoining wall is vertical and parallel to the vertical side panel so that the front panel can be cut to this measurement. However, if it is found that top measurement is greater or less than the bottom, the front panel will later need to be marked and cut in such a way that it compensates for this error, by means of 'scribing'.
If the wall and side panel are parallel to each other, measure and cut the front panel height from floor to ceiling less 6mm and at a width that is equal to the width of the opening from above the skirting. Now offer its cut edge up to the skirting board and tight up to the ceiling, while at the same time adjusting it so that it is perfectly vertical on the outer uncut edge, then temporarily pin it in this position as shown in fig 9. Place a spirit level on top of the skirting board and when level strike a line across the panel at this point. Remove the panel and run a second straight line about 3mm below the first, and cut the panel at this second line.
If the wall and side panel are not parallel to each other, measure and cut the front panel height from floor to ceiling less 6mm and to the width that is equal to the widest point of the opening from above the skirting board. Now offer its cut edge up to the skirting board and tight up to the ceiling, while at the same time adjusting it so that it is perfectly vertical on the outer uncut edge, then temporarily pin it in this position as shown in fig 9. Place a spirit level on top of the skirting board and when level strike a line across the panel at this point. Remove the panel and run a second straight line about 3 mm below the first, and cut the panel at this second line. Now place the panel back in position so that it is touching the wall and up to the ceiling and place the spirit level onto the outer uncut edge, adjust it so that it is vertical and temporarily pin it in this position. It will be found that because the panel was cut to the widest measurement, and as the panel is now up to the wall at its narrowest point, the outer uncut edge will overhang the side panel vertically, and at the same time show up the differences between the wall and the panel by means of a diminishing gap where it will be scribed and cut to that shape. After the scribing and cutting of the panel, it should now follow the shape of the wall and at the same time run up to the edge of the side panel from top to bottom.
When correctly positioned the panel should be up to the ceiling and 3 mm below the top of the skirting line, so that when the skirting board is later fitted around the box the joint will be hidden by the fact that the top panel is slotted behind the skirting.
The bottom small bottom section of the front panel can now be cut so that it fits neatly to the bottom of the box and scribed to the shape of the skirting board. Double check that the top of this piece is level, and at least 3 mm below the top of the skirting, and because this is a permanent fixture, can be glued and pinned securely in position.
With the bottom panel now in placed, offer the top section of the panel so that it is up to the ceiling, ensuring that it is also neatly lined up with the outer edge of the box from top to bottom.
If you decide that the front panel is to be detachable, use a few panel pins to hold the panel in place while the panel is measured and marked for the position of the fixing screws. It important to remember that because these screws will be visible, their positions will need to be set equally apart on both edges of the panel. This is best done by measuring the overall height from 50 mm below the ceiling at the top, and 50 mm up above the skirting board at the bottom, and dividing this distance up so that the screws will be positioned about 300 mm apart, adjusting the spaces until they fit equally. 25 mm No7g screws will be sufficient, and can be countersunk into the plywood, or raised by using brass or chrome screw cup, or plastic screw caps.
Now the front panels are in place, the skirting board can be fitted using the techniques outlined in the 'Fitting Skirting Board' section on this site.