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Tables with drop-down edges
When specifying a table with a drop-down edge remember that although the overall table thickness is 50mm, you can't just add 50mm to the table base height to achieve the overall height. The core thickness is only 25mm because it's only the edge that drops down. So you would add the table base height to the core thickness to get the overall height. Then subtract the overall thickness (including drop-down) from the overall height to establish the underside of the table top to the floor.
See the diagram below for an example.