I have come across an interesting corner bar clamp. On the head end it has two clamp points angled 45 degrees from the main bar. The clamp can be used as a regular bar clamp. It can also be used to clamp both corner pieces together at one time. When you need to clamp both pieces of a 45 degree miter joint together, this clamp, because of its head design will grip both pieces at the same time!
I don’t know where my father-in-law found these clamps. I will post the manufacture’s name and a link to the manufacture’s product page in a future post.

