I'm with Dunster. If I bought the "specialty" ruler for every project I do, I wouldn't be able to get to my sewing machine. Most of the time, your regular 6" X 24" ruler will have angle lines marked on it. May not be as fancy a gadget, but will probably get the job done. Another thing to consider is are you going to do multiples of the same project? If it's only to use for one project, I'd have to think really hard about spending the money.