There are two methods to secure a head piece depending on what features you have. Please refer to the descriptions and pictures below:
1) Screws threaded into t-nuts
A screw threaded into a threaded t-nut in a hole in the cushion. The hole in the brackets are 3/8 inch.
2) Wood screws
A wood screw threads directly into the wood. The hole in the frame is usually 3/16 inch and there are no marks on the cushion. If you are replacing a cushion you can measure to one of the original holes to locate the new cushion exactly where the original was located.