Wednesday, January 21, 2009

The Last Parts

I'm almost done with the woodworking! The last parts to make are the lectern & the cross that goes in front of the finished pulpit. When they're done, it's on to the finish. So let's get started!

Here is the plan view of the lectern, taken from my SketchUp plan of the pulpit:

As you can see from the drawing, the finished lectern will be 3/4" x 16 3/4" x 20" or so. The exact width will vary somewhat depending upon the curve I cut on the top edge. There will be a cross made from purple heart inlaid into the middle, and a 1/8" wide strip of maple inlaid around the perimeter of the lectern. Three sides will be kept 3/4" in from the edge, while the bottom piece will be kept 1 1/2" from the bottom edge. This is to leave room for a 3/4" thick book stop that will be glued along the bottom edge of the lectern. These will be the first inlays I will ever do.

While I was milling the lumber for the cap rails, I also milled the lumber for the lectern. I had a red oak board about 8 feet long and 9 1/2" or so wide. This board was almost completely flat along its entire length, with just a slight bow, maybe 1/8" along the entire length.

I cut two pieces about 24" long off of the board to glue together for this part. When I placed them on my table saw top to look for high & low spots, there was only a very small gap, maybe 1/64" or so at most, under the boards. The grain on the boards had a nice cathedral arch, and I really didn't want to rip the boards in half, so I skipped face jointing them and just ran them through the planer to clean them up & get them uniformly thick.

After that, I did the grain matching & I edge jointed the boards. I glued them to each other using cauls to keep the faces aligned to each other. Then I put the glue-up aside while I worked on the cap rails & the purple heart & maple trim.

After finishing up the trim, I took the lectern blank, sanded it flush with my ROS, and cut it to final length & width. I set the off-cut from cutting it to width aside to use as the book stop. Next I took a scrap piece of 3/4" plywood about 22" long & 6" or so wide & laid out a grid. I drove a 1" brad partially into the plywood at the intersection points of the grid & snaked a 1/16" thick piece of red oak scrap about 3' long through the brads to get the curve I wanted. I traced the curve on to the plywood, removed the strip & brads, and cut the shape on my band saw.

After cleaning up the edge with some sand paper, I traced the curve onto the lectern blank & cut it on the band saw. Then I used the plywood pattern to pattern route the curve to final shape on my router table. I was extremely pleased with the way the curve came out.

Next, I mounted a 1/4" radius cove bit into the router table & cut a lip along the bottom of the curved edge about 3/8" deep. This provides a grip for the user's fingers when they want to raise the lectern up if it's lying flat on the top shelf. I then used a 1/8" radius round over bit to ease the sharp edge on the finger grip.

Once all of that was done, I got started on the inlays. I went out & bought an inlay router bushing & bit set made by Whiteside. The kit comes with a 1/4" shank, 1/8" diameter solid carbide down spiral straight bit, a brass guide bushing with a 9/16" outside diameter, a special centering rod that you use to make sure the bushing & the router base are centered on the collet, and a special removable bushing that allows you to attach to cut the recess for the inlay & remove to cut the inlay itself.

I started by getting a scrap of 1/4" plywood to use as a template. I laid out the cross inlay on this piece of plywood. The difference between the cutting diameter of the bit and the bushing was 7/16", so I had to make the arms 7/16" wider & longer than the plan. Otherwise, the resulting cross would have been 7/16" narrower & shorter.

I drilled some holes in the template with a 1/4" drill bit & used my jig saw with the speed turned way down & orbital cutting turned off to cut the shape. I made sure I didn't remove the line with the jig saw. I then used a bastard file to smooth & straighten everything out. I checked everything with a straight edge to be sure the arms were all straight.

I measured the lectern to determine where the cross needed to go & used double stick tape to attach the template. With the bit & both bushings from the inlay kit mounted on my plunge router, I set the depth of cut to about 1/16" & went to town removing material. This went fairly quickly & left me with a very clean outline & a pretty clean bottom. I cleaned a couple of small spots that I didn't get with the router up with a chisel & 1/2 of the inlay was done.

I next cut a piece of purple heart the required size off of my second purple heart board. I attached the template to the purple heart, making sure that the grain ran in the same direction relative to the cross as it does in the lectern. The inlay would be a small piece of wood, but I didn't want to risk any kind of cross grain movement issues. I removed the outer bushing & very carefully made one pass around the perimeter of the template.

Next, I had to cut the inlay out of the purple heart. The depth of cut is still only 1/16". You need to essentially resaw the blank to cut the inlay free. I've seen Norm do this on the New Yankee Workshop a few times, and it looked easy. And it essentially is. The only tricky part is getting the rip fence setting right. Which I didn't.

I ended up with a nice slice from the blank with my inlay still attached. And even though the wood that connected my inlay to the rest of this piece was less than 1/16" thick, the stuff did not want to break! This is when I really found out just how strong purple heart is!

In retrospect, I suppose I should have taken the piece to the band saw & carefully cut it out, then cleaned up the edges with a file or sand paper. Instead, I tried to break the cross out & ended up splitting the top & bottom arms off along the grain. I used a utility knife with a new blade to try to cut the cross out, but that took more effort than I would have believed. Did I mention that purple heart is a very hard, strong wood?

In the end I got my pieces & I was able to put them into the hole I had cut out. Since everything split along the grain, everything went back together again pretty much invisibly. The parts split into more pieces when I tried to remove the inlay from the hole. The moral of this story is to resaw everything to the right thickness & don't tap the inlay into the hole until you have glue in the hole!

The next task was to cut the recesses for the maple strips. I used the edge guide for my router for three of these cuts. I removed the inlay guide bushing from the router but kept the same bit chucked in the collet. I set the fence on the edge guide 1 1/2" from the bit & made a test cut on some scrap. I verified the cut was indeed 1 1/2" from the edge. And then I cut the recess for the bottom edge, making sure to start 3/4" from the left edge.

I reset the edge guide for a 3/4" space between its fence & the bit. I made another test cut & verified the setting. I then cut the straight recesses on the sides. These went fine, though I cut one about 1/64" too far.

To cut the curved recess along the top, I used a trick I saw Norm use on the New Yankee Workshop. I took a narrow 3/4" plywood scrap, about 1" wide, and used my drum sander attachment in my drill press to round over one end. I then removed the edge guide & clamped this scrap to the router's base 3/4" from the bit. A test cut confirmed the setting. I then cut the recess, being careful not to twist the router & letting the scrap guide it along the edge. I'm happy to say this worked perfectly.

I took some extra 1/8" maple strips that I had left over from making the maple trim & ripped them in half. I had to hand plane some material off of them to get them to fit. I then carefully mitered the corners & glued them into the recesses. Then I glued the cross into its recess. The last step, after letting the glue dry, was to plane off the excess maple & purple heart using my block plane & then sanding everything flush. Finally, I shaped & glued book stop onto the bottom of the lectern.

Here's a picture showing how the lectern turned out.

Next, I made the cross. Here's a plan view from SketchUp:

The cross was made from four pieces of purple heart, each about 1/2" thick by 3/4" wide, mitered at the center. The purple heart was then wrapped with 12 pieces of maple 3/4" thick by 1/4" wide, mitered at the ends. All of these were glued to each other and a piece of 1/4" thick plywood cut in the shape of the cross. Each arm of the plywood is 1" wide. There are 1/8" wide by 1/4" deep rabbets cut in all of the maple pieces. The plywood is to act as a backer & a gluing surface to firmly attach all of the parts to each other.

I used my table saw to cut the cross shape out of the plywood. I raised the blade to full height & made a mark on the fence parallel to the front edge of the blade. I then make sure I extended all of the edges of the cross on the plywood to the edges. I set the fence to the distance from the edge of the plywood to the nearest vertical edge & made four cuts, stopping each when the intersecting line reached the mark on the fence. I reset the fence for the next two pairs of cuts, as necessary, turned the blank 90°, and cut the cross pretty much free. A little clean up with a chisel in the inside corners & I had a 1/4" plywood cross.

The rest of it was a process of carefully cutting double miters on the purple heart, then cutting the parts to final length. I glued them to the plywood & used 23 gauge pins to hold them in place while the glue dried. Then I carefully mitered a maple strip in which I had cut a 1/8" wide by 1/4" deep (actually the thickness of the plywood) rabbet & wrapped the purple heart with the miter. I used clamps only to hold the long pieces in place, but I did use pin nails on the end pieces.

And here's how the cross came out.

It's taken about 7 months or so to get to this point. I'm very happy with the end result, but I'm also anxious to deliver this piece & clean up my garage!

So next time, it's the start of the finish!

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