Planning on making a table using cherry that would be 30" deep with a 4" skirt and a 3/4" thick top. Planning on having a sewing machine sit in the middle of the span. How far apart can I space the legs before I have a problem with the weight of the machine cause a sag in the table? I like to be able to go 7p-1/2 to 8ft between legs, but this feels like I am asking for trouble. I could put a leg in the back in the middle of the span and brace from front to back inside the skirt, but really don't want a leg in the front between the two end legs.

Thanks.

Brian