Sawdust on the Floor

Hey welcome back, it’s finally time to get busy working on the trim for the upper portion of the built in bookcase in our family room. The trim for this upper portion of the built in bookcase is actually made up of three individual pieces.  Starting at the bottom of the trim, I installed a strip of dentil molding, followed by a flat piece of trim.  At the junction of the bookcase and the ceiling is a piece of cove molding. I made the dentil molding and the flat trim in my shop, the cove molding was purchased at the local DIY store.

Making the dentil molding wasn’t really difficult.  Figuring out the spacing for the teeth of the molding was a different issue. If you recall from the last posting, at the right and left ends of the book case and at the junctions of the three individual bookcases there are vertical trim pieces.  And I wanted the spacing of the teeth of the dentil molding to be setup so that a “tooth” would occur directly over these vertical pieces. In a perfect world, the spacing between these vertical pieces would be “exactly” at an equal distance apart.  However, the perfect world doesn’t exist in my shop.  The spacing is close to being exactly the same, there is about 3/8″ difference overall between the three sections of the bookcases. Not a lot, but enough of a difference that required that the spacing for the teeth had to be calculated for each section.

Since the width of the vertical trim pieces was 2″ wide, that dictated the width of the first and last tooth of each section. The width of the teeth between these points was adjusted wider or narrower as required.  The gaps between the teeth were set to 1/2″ wide and 3/8″ deep.  Starting out with a piece of 4/4 oak that had been dressed by the jointer and surface planer, I began the layout.  I marked the placement of the known teeth, where the vertical pieces meet the dentil molding.  Then using a trick I figured out a while ago, I installed strips of painters tape between the known points.  As I am trying to figure out the spacing, I mark the trial spacing on the tape.  If I got it right, then I can transfer or continue the marks onto my wood. If not, I remove and replace the tape and try again. Using a fresh piece of tape for each attempt is easier then erasing the all of the errant marks on your wood.  It’s too easy to miss a prior mark when doing the erasing, and depending on the species of wood you are working with, pencil marks can leave indentations on the wood.  Plus residue from the pencil and/or the eraser leaves more marks on the wood that you have to be sure to remove before any finish is installed. The spacing for all three sections was calculated using this method.

To cut the gaps, I used my shaper table equipped with a 1/2″ straight bit.  I borrowed the miter gauge from my table saw to act as a guide for the stock as it passes over the knife.  I also installed a sacrificial piece of stock on the face of the miter gauge for added support. For further support of the stock I used every roller stand that I have to support the ends of the stock.  I began work near the center of the stock, cutting the dados that would form the gaps between the teeth.  To help ensure that the gaps were made square to the face of the stock, I used small bar clamps to help keep the stock tight against the face of the miter gauge. After each dado was cut, the stock was moved to the location of the next uncut dado.  The bar clamp was then installed before the dado was cut.  Yes, it added a lot of time to release the clamp, reposition the stock, and then reinstall the clamp for each dado that needed to be cut.  But it helped keep the stock secured to the fence, which in turn produced straighter dados.

Once all of the dados were cut, I took an hour or so to hand sand the dados.  The router bit left the surface a little rougher then I liked.  The faces of the teeth were sanded with random orbital sander, starting at 80 grit working up to 180 Grit.  That left only one task left to be performed on the dentil molding.  Strictly for decorative purposes I decided to round over the faces of all the teeth that are not directly over the five vertical trim pieces.  Those five teeth would remain straight.  To help keep me from making a mistake and rounding over those teeth, I covered those five teeth with blue painters tape.  I installed a 3/8” round over bit in my router and went to work on the remaining teeth.  Because I was a little concerned that the corners of the individual teeth could break off if I took too large of a cut with the router bit, I rounded over the teeth by making several small cuts. After all of this work was done, I ripped the dentil molding to a final width of four inches.

The next step was to build the flat trim that was installed over the dentil molding.  This was really simple.  I dressed the stock, making it flat, square and true.  I cut it to its final length and width.  On the lower edge of the flat trim I used a ½” round over bit to treat the edge. Both the dentil molding and the flat trim were sanded, cleaned and finished before being installed.

The upper cabinets were installed with a 6” gap between the tops and the ceiling.  This was done to provide space to install mechanical “L” brackets from the tops of the cabinets and the wall.  The above molding was installed to cover this gap.  To help with the installation of the molding, I ripped a common 2×8 stud to fit the space from the top of the cases and the ceiling.  The 2×8 was then cut into several lengths.  Each piece of 2×8 was sized to fit from the face of the cabinets to the wall.  The wall had a small bow that caused me to size each piece individually. Installation of the 2×8 pieces was accomplished using woodworking glue and small nails shot from the underside of the top shelves.

The dentil molding was then glued and nailed to the three bookcases.  I worked to make sure that the bottom edge of the dentil molding and the bottom of the top shelf aligned together. The flat molding was then installed next.  It was nailed and glued to the face of the dentil molding.  There is a 2” offset from the bottom of the dentil molding to the bottom edge of the flat molding.  On top of all of this I installed Oak Cove molding at the junction of the molding and the ceiling.

With all of that work done, its finally time to build the face frames and the doors for the lower portion of the built in book cases.  But that will have to wait until the next time we meet.

Getting the three upper book cases in place and secured to the wall seemed easy, easier than trying to figure out how to trim them out. I was faced with three open shelf book cases, pretty damn boring and plain looking. I wanted something to tie them together, something to make them look like one unit instead of three separate units.

Looking at several pictures of built in bookcase, I noticed that almost every one featured wide molding along the top of the book, this wide molding often featured dentil molding which was further capped with crown molding. I also noticed that most of the vertical trim molding featured fluted case work.  After thinking about it for a while we decided to try to replicate this treatment on our built in book case.

Unfortunately, I don’t have ready access to a mill shop where I can purchase hardwood molding, so like most of us I am limited to the hardwood molding offered by the big DIY stores.  While their selection seems to be getting better, it is still very limited in variety, while at the same time the price seems to be escalating.  So it wasn’t much of a surprise that they didn’t have either the dentil molding or any fluted case work that would fit my requirements.  So, as I tend to often do, I decided to make my own molding in my shop.

I started by working on the vertical molding that would cover the joints where the three units are connected together. This same molding would be used along the left and right hand edges of the case, where the case met the side walls. My first thought was to use 1 1/2″ wide molding to cover the joints, but when I put a straight edge over these vertical joints, I noticed that they tended to wander in and out ever so slightly.  The drift wasn’t significant, but I realized that the molding had to be wider to cover this drifting.  So the molding became 2″ wide.  The length of the vertical fluted trim was set to 62 1/3″.  This is the distance from the bottom of the upper book case to the bottom edge of the top fixed shelf of the case.  I wanted the edge of the upper shelf to be covered by the horizontal dentil molding.

I went through the same process for preparing the stock for the molding as I would for any other piece of narrow stock used in my shop.  One edge is dressed flat on the jointer, then the stock is ripped to a width slightly wider then desired.  This second edge is then also dressed on the jointer. This step is to remove any marks left by the table saw blade.  After getting the edges dressed, I then make one surface flat, by passing it over the jointer.  The final step is to pass the stock through the surface planer, with the only face not yet dressed against the knives of the planer.  This ensures that your stock is truly flat and square.

The set up for cutting the flutes actually took longer than the act of cutting them.  I installed a 1/4″ diameter fluting bit in the shaper, set the fence of the shaper so that there was exactly a 1/2″ from the face of the fence to the inside edge of the bit. The fluting bit was set for 3/8″ height off of the table surface. Then I measured 2″ from the front and rear ends of the bit and drew reference lines on the shaper table.  I wanted to stop the flutes at 2″ of either end of the stock, and these lines would serve as the starting and stopping position of the stock as it passes over the bit.  I also installed a feather board on the table to keep the stock securely against the fence. Then, with my dust collector attached to the shaper and my hearing protection on, I cut the flutes into the trim stock.

With the bit at full speed, the stock is slowly lowered down onto the bit.  The trick is to lower the stock exactly the mark 2″ from the rear of the bit. I find that this is sometimes easier said than done.  I finally resolved that it’s better to lower the stock so that it’s just past the end marker, and then carefully pull the stock back slowly until you reach the first marker. If you choose to use this method, ensure that you have the stock secured with a good feather board, and that the contact between the stock and the fence is very tight.  Otherwise the stock can be thrown back at you. It also goes without saying, use push sticks to move the stock past the bit. 

When the stock reaches the other mark on your shaper top, stop pushing and turn the machine OFF.  It’s safer to remove the stock after the bit has stopped turning than to try and remove it while the bit is spinning. Now turn the stock end for end and repeat the process to cut the other flute. Doing so will hopefully produce two flutes that are 1/2″ from either edge, and a 1/2″ apart from each other.

I found out that when I pulled the stock back toward the bit, it tended to burn the wood. So a little more hand sanding was required to clean up the flutes and remove any burn marks.  For most of the flutes, I simply wrapped pieces of sandpaper over a 1/4″ dowel rod,  for the ends I used the same sandpaper, but switched to a rubber sanding pad that conformed to the shape of the flute.

The five fluted trim pieces were sanded and finished using the same processes as the book case.  After they were dry they were installed with glue and finish nails from my pneumatic nail gun. As they were installed, I used my 4′ level to ensure that they went up totally vertical and that they were centered over the joints.  The two outside pieces were scribed into the side walls and the 4′ level was used to ensure that the inside edge of these pieces were installed totally vertical. 

I know that I should trust my ability to measure, but I’ve learned the hard way that it’s much better to mark, rather then to measure. With that concept in mind, I wanted these vertical pieces in place before I laid out the dentil molding. The reason for this is that I wanted the teeth of the dentil molding over the five vertical fluted trim pieces to align perfectly with the vertical pieces.  I realized that the spacing between the fixed teeth might have to be adjusted, and I could live with that, just so that the five vertical pieces aligned correctly. So knowing the width of the room, and the placement of the five vertical trim pieces I could calculate the spacing  between the teeth. 

But it’s time to clean up the shop for the day and get cleaned up for dinner.  Hope to see you later.