The problem with the vintage machines that do the buttonhole stitch using cams, is that they're not very adjustable. I use my new machines for doing buttonhole applique, because the vintage ones just can't get the exact depth of stitch and as close together as I'd like. This is one of the only functions that I prefer a new machine over a vintage one for. I make sure all my applique can withstand many years of washing and abuse, and I've never liked the product of the cam/buttonhole stitching in any of my cam machines.