Keyhole Shelving Unit Joining Brace

I bought a “Pinnacle” brand shelving unit from Bunnings, The vertical posts are half height and joined in the middle. One shelf is meant to be in a fixed position to strengthen the join. Unfortunately I did not want a shelf in that exact position. So I only attached horizontal pieces on 3 sides. The front side was weaker than I'd like, so I designed these braces for extra support on the missing side. 

It should be possible to use this on all 4 posts if you are short on the horizontal pieces. There is a 45 degree chamfer on all pieces to make it look thinner from viewable angles, and to allow them to fit if you need two braces on a single post.

Simple 2 part brace, joined with Nuts & M5 Bolts (12-16mm). I've chosen to use bolts as they will be the most secure and I want these shelves to handle plenty of weight.

Note: there are 4 different pieces for front & back, left & right. (Left from your point of view, looking at the shelves from the front)

I've used sparkle ABS for the front plates to give a similar look to the original frame.

Designed in OnShape if you would like to make changes