What Steve said. It takes what is known as back clamp feet. I don't know that you'll find a modern 1/4" foot to fit it. Back clamp style attachments do show up on Ebay from time to time. I've seen them mixed in with other attachments before too so it pays to pay attention.
Rodney
EDIT: All I've ever used for piecing is the standard foot and a seam guide set for 1/4" from the needle.