Sawdust on the Floor

Over the past 30 plus years we have made several changes to our home. The biggest ones were the conversion of the way too small garage into added living space, and a 320 Sq foot addition onto the back of our house. The converted garage area allowed us to enlarge the kitchen area, and create a formal dinning room. As part of that conversion, we also added a window in the now enlarged kitchen area. This new window not only added air circulation to the kitchen area, but it helped balance out the layout of the kitchen.

Fasting forward several years, we decided to put an addition onto the rear of our house. That kitchen window that we really loved just had to go. The wall that had held it became an interior wall, so the window just wasn’t practical. We did however manage to reuse, or repurpose the window. It was moved to one of the walls of the addition. Despite every thing we loved about the addition, the kitchen area now looked unbalanced, something was missing, the window.

Our solution was to add a mirror that mimics the looks of a window. I would like to tell you that the idea was an original, but the truth is we saw a mirror like ours during an overnight hotel visit. After looking at several poorly made duplicates in our local stores, I decided to make my own.  The process I went through to build this mirror was a bit complex but I think the results were worth it.  Read on to find out how I built this project.

I have made a couple of things before that included a curve edge before and have learned a couple of things that are not in the books. The first is that no matter how well you may think you understand the math and all the angles, somehow it never works out the way you  think it should, or maybe that’s just in my shop.

So to help keep Murphy’s law out of my shop, I tried something different on this project. I took a 4’x4′ piece of ¾” plywood, and laid out the desired curve on that. When I started this part of the project, I had intended for this just to be a layout device, but I later decided to use it for gluing and clamping. I started by dissecting the plywood down it’s vertical center, This line would become the reference point for the curve. We had decided that we wanted the outer width of the mirror to be 32”, so from this center line I placed two vertical lines, equally spaced 16” from the center.

Now if my math is correct, the top of the arc should be equal to the distance from the center line to either edge point, or 16”. But since I refuse to assume anything. I verified that, by using a yardstick compass, also known as a beam compass. The yardstick compass is a set of adjustable points. One is for the center point of your arc, and the other which contains a pencil, is set to the outer edge of your arc. I simply placed the center point of the compass approximately 24” from the top of the board on my center line, verified that it was an equal distance from both vertical edges, and prescribed the outer arch. OK, where did the 24” come from? It was an arbitrary number, I knew that I wanted the arch to be 16” at its peak, but I also wanted to have some room left on the layout board for clamping , so I picked the 24” value.

The entire mirror, with the exception of the munton bars in the arch and bottom portion, is constructed using 6/4 Oak.  I had chosen to make the rails and stiles of the mirror 2 ½” wide, so, keeping the compass at the same setting, I simply moved the center point 2 ½” further down the center line, and prescribed the inner arc.  I also drew, the two vertical inner lines for the stiles. Now I had a real good idea of what the top of the mirror would look like.

The next question was, how many segments did I want to use to make the arched top. I tried several different layouts, but in the end, I decided to use four segments. So lets see, I have a half circle, which is 180 degrees, and I want to divide that into 4 segments. And each segment has two ends, so if I divide 180 by 8, I end up with 22.5 degree angles.

Now that we have the math out of the way, let’s cut some wood. My first step was screw to a piece of 4/4 Oak along the horizontal line, that was even with the intersection of the arch and the vertical rails on both sides. I spent quite a bit of time making absolutely sure that this line was square to the center line, and to the vertical rails. Everything I did after this was going to be referenced off this line.

I then had to determine the length of each of the segments. I simply scribed a 45 degree line from the center point out to each side of the arch. Measuring along the arch, I now had an idea of how long the segments needed to be. Because I know that the angle stops of my miter saw are not perfect, I choose to make trial pieces of each segment.

This drawing may help make a little more sense out of what I am trying to say.

I started by setting the miter saw to 22.5 degrees and cut a trial piece for the first segment. Actually I cut several trial pieces, but only cut the 22.5 degree cut one end. The lengths of the additional trial pieces was left long for now. At this point, I also made up one of the final segment pieces, cutting the preset 22.5 degree angle on one end just as I had one the trial pieces.

On the first trial piece that I used, I cut the angle on both ends . Taking the piece to the full size layout, I placed it into its intended place. Guess what? When I held it tightly against the reference board, the other end did not line up on the 45 Degree line. So I tweaked the miter saw adjustment, and cut an entirely new trial piece. I then marking and discarding the first piece so I wouldn’t accidentally try to use it again. I Placed this piece on the layout and checked the fit. I kept doing this until I had a piece that fit tightly against the reference board and the 45 degree line. Now using this piece as a template, I cut the other end of the final stock, for the first segment.
My next step was to secure this first segment to the layout board. From the underside, I attached screws to the first segment piece, pre drilling because I didn’t want to split the wood. Before I attached the piece, I cut #20 biscuit slots into both ends of the segment.  Now I moved onto the second segment piece. The action is basically the same, as for the first piece. The only difference is that I used the end of the first segment piece and the center line as my guides. When I had a piece that fit onto both ends, I cut the final stock, cut the biscuit slots in both ends. I applied glue and the biscuit to the intersecting joint, clamped it into place, and attached it from the topside of the plywood using pre drilled screws.

After letting this part set up, I moved onto the third and forth segments. After I had the four segment fitted correctly, I had to remove the horizontal reference board, to allow the biscuit to be installed, between the third and forth segment. Everything was left to dry for a couple of days before I moved onto cutting the actual arch.
While the glue dries and everything stabilizes, I think it’s time for me to call it a night and close up the shop. I plan to be back in the shop soon to work on this project, I hope you will join me.