There are lots of times when you need to clamp and glue several boards together edge to edge. You know how it goes, you get everything set up, put glue on the edges and everything starts to slip and slide, and you can't get the edges to align correctly. It could be mahogany boards for a new transom or just shelves for the workshop. By making a few of the blocks shown in the picture, it's easy to align the edge of the planks. The cost of the blocks is nothing as they can be made from scrap lumber. The best way to make them is to bore an inch and half diameter hole through a piece of lumber then cut them down the middle on the chop saw. The ones in the picture are pretty dressy but do make them carefully, and they will last years.