Seam Allowance Guide
 

I saw this ad http://www.seamallowanceguide.com/ and think it's a neat idea, but why not just buy a magnet that is 5/8" thick and stick it to your scissor? It sure would cost less. Then just follow the edge of the magnet. They are pretty cheap at the hardware store.

I like your idea of the magnet better.

That is a clever product. I have this very old thingy that is made of metal and slides on the top bar of the scissors and lets you adjust the distance you want to measure out when cutting. However, it only goes to 1.25 inches. Using a magnet, you could even use a small ruler (or the broken off end of one) and attach it to the scissors for a guide. Then you'd have a whole range of cutting widths....

Thanks for sharing this!

Great idea. Off to the store to get a magnet. Thanks for sharing your idea.