Like all other scarf joints, you can use this joint to create a longer beam out of two shorter timbers. The cogs in this joint are the t-shape projections in the tenon. Since they help lock the joint in place, they also increase the bending strength against horizontal loads. In this example the stop bladed scarf joint with cogs and pegs is secured with vertical hardwood pegs.
Although it takes a bit more effort to cut this than a simple half-lap joint, it is extremely strong and enhances the beauty of any frame. You will be happy to show off your joinery skills with this stop bladed scarf joint with cogs and pegs!