What technique is this used to strengthen a miter joint?
Well, a good solution for both of these problems is to add a spline across the miter joint. A spline that's only as wide as a saw kerf can keep the miters perfectly aligned during assembly. And it adds both mechanical and gluing strength to the joint. Cutting miters on the workpieces is where you start the job.
How do you reinforce a corner?
Miter joints are stronger than butt joints. The method of joining the two mitered pieces will determine it's strength. ie: use glue, with screws, nails, splines or biscuits to make it a more secure joint. Dovetail joints are the amoung the strongest joints.
Are miter joints stronger?
How do I make sure my cuts are straight?
How do you make miter cuts better?
How do you ensure a straight cut?
Do you need to reinforce miter joint?