I will start by saying I am embarrassed to post this. I cannot saw a board at a 90* angle using a handsaw. If I have to saw a 3" wide board at 90* the cut will veer off. A magnetic saw guide for sawing right angles would keep the saw straight through the cut. In the past I have used a magnetic guide for dovetails and using the guide helped me to the point where I no longer need to use it. Of course, my dovetails are usually only 3/4" deep. I really don't want to make such a device. I would like to hear from folks who own a 90* saw guide and what they like or dislike about it. Thanks.