I’m going to cover reinforcing some of the holes for the tetris shelves. At the inside corners, the holes for the shelf pins are very near the edge. I’m afraid that these holes would tear out under moderate loading. To reinforce them, I used some aluminum angle. This ended up being an after thought once the shelves were built. As a result it caused me more trouble than it should have.
First, I went about the lazy way of installing the aluminum by just sitting it on the surface. Once it was done I really didn’t like it and instead flush mounted them. Still, I thought I’d talk about it anyway.
To transfer the location of the holes I used these little center finders that I picked up a while back. They have a point on one end and cylinder on the other. The non-pointy end is placed in the hole. You then put the aluminum on top of it and tap with a hammer. This creates a small dimple in the aluminum that you can use to determine where to drill.
I drilled two sets of holes in the aluminum angle. The larger holes are for the pins and the smaller ones are for the screws that hold it on. I then took the aluminum piece over to the shelves and used them as a template for where to drill pilot holes for the screws.
Then it was back over to the drill press to countersink the screws.
Here’s what they look like when installed.
The aluminum pieces worked but I didn’t like how they sat above the surface.
To flush mount the aluminum pieces requires removing 1/16″ of the material under where the pieces sit. This shifts the width of the area where the material is removed as well which needs accounting for. As the shelves were already built, this greatly complicates the matter of removing the material to flush mount. A router is a great way to do this, but my regular one was to large to fit vertically. Even if it would have, the large base would have kept the bit far from the edges. Luckily there’s a line of small routers known as laminate trimmers. You can guess what they’re primarily used for. They have a 1/4″ collet and accept normal router bits. I picked up one of these to remove most of the material. To limit how far the trimmer moved I clamped in a few stop blocks. One limited the width of the pocket and the other limited the distance from the edge. This made using the trimmer quick and easy.
The router bit is about one inch away from the edge of the base on the trimmer. As a result, the last inch of material had to be removed with chisels. If your depth of cut with the chisel varies some it is ok because the area is covered by the aluminum. Once the aluminum piece fit flush, the center finders were used again and then it was back to the drill press.
I chose to glue the aluminum pieces in this time instead of using screws. I was worried about material thickness under the aluminum and it looks better this way. Gorilla Glue says it can be used on wood and metal. I scuffed the bottom of the aluminum and gave it a try. It worked well other than the expected squeeze out that comes with this kind of glue. Here’s the piece installed.
After that was repeated multiple times, I finally finished the shelves. Here are a couple pictures in different configurations.