Keep on playing with Maggie May. You can use a piece of Blue painters tape laid down on the bed of the machine for your 1/4 inch seams. As a suggestion, I use 1/4" graph paper to stitch on when I am trying to determine stitch length or 1/4" settings on a machine that does not have a manual or for reference when I do have a manual. I keep the paper with the manual if I have it or in three ring binder that I keep for my vintage sewing machines. I do think that there is a seam guide attachment that can be used with your 221. It screws onto the bed of the machine. Check your attachment box if you got one with your machine. I know, you are going to ask what it looks like. I am going to see if I have one for my 221 and take a picture for you amd post. If not I will take a picture of one from another machine.