Togalosh":3s4gkvf8 said:
You say a 30mm thick (side to side ? ) apron.. I thought the height (top to bottom) was the crucial measurement... What would you recommend for the height (top to bottom ) ?
You raise an interesting point. The reason I emphasised the thickness of the apron is because the width (the top to bottom measurement) is constrained by the simple ergonomics of table design.
You don't want the top of the table to be much higher than about 30", in fact if the table will be regularly used by children you might want to lop an inch off that. But at the same time you don't want the bottom of the aprons to drop much below 23" or you won't have enough room for your knees to comfortably fit under, personally I prefer 24"-24 1/2"" of clearance. Dining chair seats are normally about 16" or 16 1/2" high and you want at the very minimum 6 1/2" thigh clearance, and 7 1/2" or 8" makes for a much more pleasant eating experience.
Because I mainly make tables designed for adults to eat at, they tend to have the top of the table at 30" high, and the bottom of the apron at 24 1/2" high. Given that the top will be 1"-1 1/4" thick it means my aprons are normally a shade over 4" wide. So with the width of the apron constrained, for a long table I'll therefore make the apron thickness at least 1 1/4", or 30mm. To give you an idea of what the proportions look like, here's a 2.0m long, breadboard end, eight seater table that I regularly make. I use the same basic scantlings for anything in the range 2.0-3.0m long.
Hope that helps.
Incidentally, building on your South African comments earlier, if you ever get the chance you should pop into Surrey Timbers. The guy who runs it is South African and he keeps some amazing African timbers in stock, stuff that otherwise you'd never find in this country.