A common question we are asked is if you can buy particular steel bed frame parts to make a king size head board adapt to the bed frame of a queen size mattress and boxspring? The answer is no, especially if you want your headboard to look normal and acceptable to others. A steel bed frame that fits a king size mattress is 76 inches wide. The frame is designed to fit and accommodate a king size headboard. The king headboard all though slightly wider than the mattress and steel bed frame by an inch or so is built as such for aesthetic purposes. The king headboard is considerably wider than a queen size mattress and bed frame which measures a significant 16 inches narrower. By using a king headboard with a queen mattress and bed frame it would leave 8 inches of king size headboard exposed on each side of the mattress and would be very unattractive. Here is a link to all standard mattress sizes to help you better understand.