Sunday, November 16, 2008

Of Mice & Men & Design Changes

Back in October, I decided that the lectern was too plain as originally designed. The design for the improved lectern appeared in my head almost as a vision. I could see what I wanted to do. So I put together the change in Sketch-Up in a couple hours. The picture below shows the idea I had.

Essentially, the lectern will be shaped like a tomb stone with a 1/4" wide strip of maple inlaid 3/4" in from the edges. And there will be a purple heart cross inlaid in the center of the field created by the maple inlay. I'm going to need to purchase an inlay kit for my router to do the inlay. Luckily, these kits aren't too expensive. These will also be my first inlays. I intend to practice a little before doing it for real.

Through out the summer, my pastor kept asking me to add "handle bars" to the pulpit design. At first I thought she might be joking. But she often feels dizzy while preaching as the Holy Spirit works through her and felt she needed something to hold on to, in order to keep from falling over.

After determining that pastor wasn't kidding, and after making the obligatory jokes about putting chopper handlebars & a seat on the pulpit so she could take the pulpit for a spin, I began to wonder exactly how I was going to meet this request.

A number of ideas presented themselves to me & were discarded. One was to actually get a set of motorcycle or bicycle handle bars & add them. That got discarded quickly -- I just couldn't see how to make that work. And I don't think anyone would take seriously any pastor preaching from behind a pulpit so equipped.

Then I had the idea for what I call the "towel rack". This would be two triangular gussets made of maple a full 3/4" wide rabbeted into the corner posts of the center box. Between them would be a rod or dowel made from purple heart a full 1" to 1 1/2" in diameter. This would give pastor a place to hold on. But this still didn't work for me. All the pulpit would need at this point is a pair of wheels in the back & you could tilt it back & push it around.

Then, one night while driving to the Men's Ministry meeting at church, I had another vision of a change to the pulpit. As originally designed, the boxes had nothing but square corners. I saw the pulpit with the inside corners of the center box & the adjacent outer boxes cut off at an angle. And our Elder Jack then suggested cutting an oval hole through the partitions.

This idea appealed to me so much that I started working on modifying the drawing that night. After a few hours work, I came up with the design shown in the picture below.

Since the partitions are made of ply, I first cut the corner off of one of the outside boxes. I then transferred the line to other outside box so they would be cut identically. I then cut the corner off of that box. Next I transferred both lines to the center box & cut those corners off. These cuts were made with my circular saw & straight edge guide. Because my straight edge guide uses a carriage to hold the saw, I couldn't get the blade low enough to cut all the way through the corner posts, so I had to finish these off with my flush cutting saw.

The boxes were then bolted back together & everything sanded with my belt sander. The photo below shows everything after all of these steps were completed.

The next step was to make the handles. I didn't just want to cut oval holes in the ply, as that would make the plies visible. Plus, I wanted to round over the edges of the hole to make the handle more comfortable to hold, and there just wasn't enough room to get a full size 2 1/4 HP router base in there at this point.

So I decided to make the handles out of solid red oak, cut notches to accept the handles in the ply, and glue the handles in. The next step, therefore, was to actually make the handles. Since the boxes come apart, I would have to split each handle in half & glue each in to a different ply partition after the notches were cut.

As you can see from the Sketch-Up image above, these pieces are parallelograms. I drew the shape on one of the ply partitions & set my bevel square to the angle. I then used the bevel square to set my miter gauge. It turns out that the correct miter gauge setting to cut the shape in the drawing is about 25°, give or take a few tenths of a degree.

So I took the two failed bottom rails for the center box & ripped them to 2 1/2" wide. I then cut them into blocks for the handles. After cutting 5 blanks from the two rails, I layed out the oval holes.

Originally, I planned to make the holes by drilling 3/4" holes at the ends with a Forstner bit, then clearing out most of the waste with the same bit. Then I'd clean everything up with my chisels. I also figured I'd use one as a pattern & use a flush trim or pattern bit to get all 4 holes identical. It's important that someone holding the handles doesn't feel any uncomfortable edges because of inconsistencies in the shapes when the boxes are bolted together.

Well, the first attempt didn't come out very well shaped. And the holes were a bit tight on my hands. And when I tried to pattern rout one of the other handles, I inadvertently made a climb cut & the handle split in half. Luckily, I was able to glue that blank back together & you can't tell where the split happened without looking at the end grain.

I decided the best way to recover was to increase the hole diameter to 1 1/8". This was the minimum size I needed to remove all traces of damage to the grain within the hand hole. This time, I did a better job of cleaning everything up & the handle came out much better, as you can see in the next photo below.

Next, I ripped the four blanks to the thickness of the ply and rounded over the hole edges using a 3/8" round over bit in my router table. The photo below shows the handle after rounding it over & sanding everything smooth.

That's enough for now. More on installing the handles next time.


Neil....a Furnitologist said...

Hey Big T.........I see the spirits are on high. Love it!! Pulpit progress keeps moving moving along....Neil

Tony V said...


I have an update I have to write & get out. I'm further along than where I left off.

It's too easy to let your spirits flag at a time like this. I refuse to let that happen. I will be OK & I will get a new job. It's just a question of when, not if.