There are several different types of corner braces such as inside corner braces, flat corner braces and “L” braces. All of these types of braces serve the same purpose – to keep boards secured in a square or rectangle keeping them even or “square”.
I had the opportunity to use a set of inside corner braces when building a stool. There are screw holes in the two sides (which will allow the user to secure the braces to framing) as well as in the flat, triangular top (to secure a top or seat). The inside corner braces are really, really easy to install. For this demonstration, I am showing how I installed the inside corner braces on the stool frame then attached the top.
So, I have the stool frame assembled which includes legs and aprons. In order to use the inside corner braces, the aprons have to be directly perpendicular to each other on the inside of the legs. I used #6 x 3/4” wood screws and secured the inside corner braces in each corner where the aprons are joined to the legs.
Then, I positioned the frame on the underside of the seat and secured the seat to the frame with the #6 x 3/4" screws through the flat, triangular top portion of the brace into the seat. Super easy!
The inside corner braces would be used on the framing and top of a table in the same manner. They could also be used on the top portion of a box or trunk (without securing them to the top or lid) which would help support the corners if the top or lid is heavy.
Uses for other braces such as flat corner braces and “L” braces can also be decorative. They can be spray painted and used on photo or mirror frames, or as a decorative element on chair or table legs. They can also give an “industrial” look to furniture projects!