Sawdust on the Floor

It’s Saturday morning, the sun is shining, the coffee is hot and it’s time to get back to work on the arched top mirror. And before I forget to say it, “thanks for coming back”. If you missed the earlier parts of this project, here are the links to Parts 1 and 2.  Woodworking Project -Arched Top Miror Part 1 and Woodworking Project – Arched Top Mirror Part 2. 

Okay, now that you’re all up to date, let’s get to work.  The rails, stiles and top arch are all done, and the back of the mirror has been prepared for the actual mirror itself. All that remains is to fabricate and install the decorative trim that will go over the mirror. I wanted to be able to get you a firm definition on what these pieces were called, some printed materials I have read called them muntons, some mullions and some mutton pieces. But the truth is the more I read the more confused I get. Here is the way I understand the differences between muntons and mullions. A mullion is a structural member that can be used to separate a window, whereas a munton is a non structural piece. Both can used to create true divided lights, and both can be used both on interior and exterior work. And for a mutton, well that’s the meat of a sheep. So for our discussions these things are muntons.

Enough with the English lesson, let’s make some saw dust. To create the muntons, I had purchased a special set of Freud 99-270 1-17/32-Inch Divided Light Cabinet Door Router Bits that were designed to cut both profiles in the wood. I started out by working on the inside of the rails, stiles and the arched top by installing the bit shown here on the right.
I used the same techniques that I had when I formed the outer profiles of the mirror. I placed the entire mirror on a scrap piece of plywood, and secured it using several clamps. Because the potential for the router tilting on the small surfaces of the rails and stiles still existed, I temporarily installed pieces of 6/4 scrap stock on the outside of the mirror for added surface area and support. Then I carefully routed out the entire interior edge of the mirror. I took caution in the corners the keep the profile consistent and even.

I found that the radius of the bit was too large to work into the corners of the arch. I took the router bit as close as I could, and then went to work on the corners with a combination of sand paper, sharp chisels and riffler files to complete the profiles. It felt really good to get back to some old fashion hand woodworking for a while.

This is the same profile that would be cut on to the sides of the muntons, and that really wouldn’t be a problem, other than the safety issues involved with working with very thin pieces of stock. The issue was how to cut the opposing profile into the ends of the these very thin muntons.

I had used my large plunge router to cut the profile on the interior edge of the mirror frame itself, but elected to use the shaper table equipped with the same bits for the muntons. I know from past experiences that it is not only unwise , its very unsafe to try to cut the opposing profiles on thin, unsupported stock. The best case scenario is that the work is damaged by tear out, the worst case is that the stock is caught by the router bit and forcefully ejected from the work surface. A very dangerous and scary situation.

My solution was to cut the opposing profiles all at once. I had determined that the ideal width of the muntons was to be 1″ wide, and that I would need one long piece for the center vertical munton and four shorter pieces. Two for the horizontal pieces on the bottom of the mirror and two for the upper curved area. I took a piece of 4/4 stock that had been squared using the jointer and the surface planer, and cut it to an overall length of 40″ and 6″ wide. My plan was to rip it to the correct 1″ width after the end profiles were cut. I figured that I easily get the vertical center piece from one length and could cut the remaining pieces in half length wise for the remaining pieces.

I also cut a couple of other pieces of stock to the same 5″ width to be used as trial pieces, and to act as backer pieces when I ran the stock across the router bit. I also chose to use a shaper sled to help support the wood. This sled runs in the miter gauge slot of the shaper, while the clamps on top, keep the stock secured to the surface. And more importantly, it keeps your fingers away from the spinning router bit.

I started working with the scrap pieces, cutting profiles in the ends and then attempting to match them to the profile of the mirror. I adjusted the bit height and the shaper fence either in or out until I got the precise profile match. Then I took my good stock piece and ran it across the router bit. I used one of the scrap pieces as a backer piece to prevent tear out at the rear of the cut. Logic would tell me that process should NOT shorten the board, but because I like to verify everything, I checked. Any deviation from the original 40″ would have to be accounted for.

I found that because of the way I had set everything up, I actually took 1/16″of an inch off the length. Knowing this length, I knew that I had to add it back into the length I was going to cut for each piece. My measurement of the inside of the mirror, top to bottom was 27 7/8″ long. I added back my 1/16th of an inch, and cut the board to 27 15/16″. Now I ran this board back over the shaper, cutting the end profile in the other end of the board.

Taking the board back to my table saw, I carefully ripped a 1″ piece off the edge of the stock. This was to be the vertical munton. The remaining stock, which already has the end profile on both ends was going to become the horizontal munton and the two muntons for the top. I placed this center munton into place, and carefully centered it. then measured the distance for each of the two horizontal muntons. After adding the 16th of an inch back in, I cut that length off of the stock.

The remaining 5″ wide board was still wide enough to safely use on the shaper, so I cut the end profile on this piece. Once again I took the stock to the tablesaw and ripped the stock into two 1″ wide pieces, creating the horizontal muntons.

I modified my original drawing of the projected mirror to include the muntons in the arched area. My original concept was to have four muntons, but after laying it out, it just looked too busy, so I ended up with the three as shown. The math on this was pretty simple, the total arch was 180 degrees so each segment had to be at a 60 degree angle. So my first task was to cut the angle at the junction of the muntons and the horizontal rail. Now my miter saw won’t cut a 60 degree angle without some fancy modifications or jigs, but it will cut a 30 degree angle. which is the complementary angle for the 60 degree cut

Thinking about what I was trying to do, brought me to the understanding that for each of the remaining two muntons, one end would need to be at the 60 degree angle, while the other would be very close to zero. I also realized that I would be better off cutting the angled end first, and then fitting the square for length, rather then the other way around. So I put the remaining stock into the miter saw and cut off the non profiled end at 30 degrees.

With the fence of the shaper sled at the same 30 degrees, I ran this end of the stock across the router bit to create the end profile. Now I took the stock to the table saw and ripped it into two 1 ” wide pieces. Now the fun part of the project, I carefully measured the length of the two angled muntons, added back in my 1/16th of an inch. Being very careful to remember if my measurement was on the inside or outside of the angle, I cut each piece to the final length.

Once that was done, all that was left was to cut the profile in the end of each of these angled muntons. To add a safety factor and to prevent tear out, I used a piece of scrap wood behind the muntons when I cut them.

As I was going along on this part of the project I kept making dry fit tests to ensure that I hadn’t goofed. Thankfully I was still good to go so I continued to the next step, cutting the opposing profile in the sides of the muntons. To do this I had to put the same router bit that I had used on the insides of the mirror into the jointer.

To get the correct height adjustment on this bit, I used the mirror it self as a standard. With the bit at the correct height, I cut a trial piece, tweaked the height until I was happy with it. Then using two feather boards, one on the vertical edge to keep the wood down on the router bit and one on the horizontal edge the munton tight against the router bit, I cut the profile on both sides of the muntons. I used two push sticks to guide these small pieces across the router bit, I didn’t want my fingers any where near the router bit while it was spinning.

One last task, and that was to cut the bottom off of the muntons. The router bit set I was using cut the design for true divided light muntons, I wanted to use a single pieces of mirror on both the bottom and the arched top. I simply ripped off the bottom edge of the muntons, so that the muntons would lay flat against the face of the mirror.

After hand sanding each of the muntons and the inside edge of the mirror, I glued each of the muntons into place. Glue, blue painters tape and small spring clamps were used to secure the muntons in place while they sat up.

There is nothing more that I can or dare to do on this project today. I don’t want to rush the glue up, so its time to clean up and see what other kind of trouble I can get into. As soon as the glue is cured, then its a complete sanding and finishing. More on that later. Check back in a couple of days and we’ll finish this project up in Part 4.

Related posts:

1. Woodworking Project – Arched Top Mirror Part 2
2. Woodworking Project – Arched Top Mirror Part 1
3. Woodworking Projects – Hall Mirror