Tip for sewing HS Triangles and other angles
 

My issue would be holding the cardboard securely, but a great idea for experienced quilters:
http://www.quiltmaker.com/blogs/quil...k-stitch-flip/

Yeah, it seems like a good idea in theory but I wonder how hard it would be to execute. I've seen it done when you put a piece of tape on your machine's bed to use as a guide.

It's easier, to just throw a ruler across the corners, then mark with a pencil or water-erasable marker.

I've got a plastic template that attaches to the foot, sticks out in front, and provides a visual guide. It's like a ruler with a dotted line down the middle. You keep the dotted line on the diagonal - or any other line you want to stitch - it works fine once you get used to it.

Try a strip of fine grit sandpaper; it should stick to the fabric nicely!

There is a guide that fits on the machine over the face plate that has all the angles marked. I don't have one nor have I tried it, but if you did a lot of that type of seam, it might be worth looking into.

I wonder if it would work to use an Emery board as a guide.

I think this is a good idea, it would have some "grip".