Narrow hemmer foot driving me insane

[Allington]

It looks so easy on the videos. Quick, simple, beautiful hems.

Mine go lumpy, twisted, and the stitch doesn't always catch the folded fabric, but it is a straight stitch machine (Singer 201) so I can't use a zig zag stitch or alter the position of the needle.

Any advice?

I don't have any experience of that foot but would this article be of any help?

www.threadsmagazine.com/2008/11/20/mastering-the-narrow-hemmer-part-one