Christmas Light Tree

In recent years my wife and I have traveled out of the area at Christmas to visit family and have not put up a Christmas tree at home.

This year I decided that I wanted some sign of the holiday in the house, so looked around at what I had on hand. (What a friend calls “in inventory”).

I found plenty of things that I could use for a Christmas Light Tree, so I went ahead and built it.

What I found in inventory:

Two Christmas tree light strings, each with 100 lamps and 26 ft long.

2 x 2 ft piece of 1/2" plywood.

Long piece of black 1/2" pipe

White filament for my 3D printer

Corn Husk tree angel

Number 6 wood screws

Tools I used:

Table saw

Hand saw

3D printer

Screw driver

Pipe cutter

Step 1: Designing the Tree

I used two long strings of tree lights, 100 white lamps each and about 26 ft long, according to the box.

I did a quick measure of the living room picture window and decided a 6 ft. tall “tree” would look right from outside. Those two numbers and some arithmetic told me that I could have 8 vertical runs around my light-tree, using just the two strings of lights. (Needed 8 x 6 = 48 Available 2 x 26 = 52)

I found a length of ½ inch black aluminum pipe that was long enough, and cut it to 6ft.

I decided that the top should be about 4" diameter, which was big enough for the tree angel to sit on.

I only had a 2 x 2 foot piece of plywood, so the base was 2 x 2. The tree might look better if the base was a bit larger, perhaps 3 foot diameter.

Step 2: Designing and Building the Top

I have a 3D printer and used that to design and build the top for the tree. It could be done in plywood, if you don't have a printer.

Having the printer allowed me to do a design on my PC using TinkerCAD, and then the 3D printer did all the work of making the actual part. The design took about 1/2 hour, and the printer took less than an hour to build the actual part.

I made the top 4" in diameter which was big enough for the Tree Angel to sit on comfortably, and still have the light strings fit on around her.

I measured the cross section of the wiring on the light string to decide the width and depth of the 8 notches.

I put a hole in the collar for a screw to clamp the top to the 1/2 inch pipe. Screws will self-thread into the soft plastic, and I did that here.

A picture of the TinkerCAD design, design file (STL), and actual part are included.

Step 3: Designing and Building the Base

For the base, the largest piece of ½ inch plywood I had was 2 ft square, so I used that. I think the light-tree would look better with a larger base, perhaps 2 ½ to 3 ft diameter.

I considered cutting the circle with a jigsaw, but ended using my table saw, to get a round circle easily.

I clamped a board with a hole in it to my table saw, as a pivot. I adjusted the position of the hole in the board so that its center was one foot from the saw blade and aligned with the center of the blade. Then I clamped it in place.

I drilled a hole in the center of the 2 x 2 piece, set it on top of the clamped piece, and stuck a post through both holes. This allowed me to rotate the 2 x 2 past the saw blade, cutting a circle. I lowered the saw blade and I did a shallow cut part-way through the 1/2" thickness. Then I raised the saw blade and circled around again for the full depth cut. The goal was to reduce the blade scraping on the wood as I rotated the piece. Even so, this was not a pretty process, creating much smoke and burned edges on the piece from unwanted friction. I am sure you can find a better way of making the circular piece.

I had located the center of the 2 x 2 the usual way, drawing lines diagonally from opposite corners, and drilling where they crossed.

I similarly located the 8 notches around the piece. First drawing a line across the piece through the center hole, by eye. (This might be better done before the hole is drilled, but it was accurate enough for this project.) I next drew a line perpendicular to the first. That located 4 notches. For the other 4, I measured between two adjacent lines at the edge, and marked the ½ way point. I repeated that on the opposite side. And then drew a line through the marked points and the center of the hole, edge to edge. I repeated that on the perpendicular, and that gave 8 edge locations. I estimated the diameter of the light string cord, and drilled 8 holes to form the base of the notches. I then just sawed each notch to the hole.

I took the pieces that were cut off when turning the 2 x 2 into a circular piece, trimmed off the points, and screwed all 4 under the plywood as feet. This lifted the base, which allowed me to string the cords, and hide the plugs under the plywood base. It worked fine on my carpet, but if you are doing this on a wood floor, you probably need thicker feet than the ½ thick ones I used.

I screwed a scrap of plywood under the center hole, to form a bottom stop for the post.

Finally, I painted the top side and edges, of the base white. I didn't bother sanding or otherwise preparing the base for painting. For this project, paint covered it all, including the burn marks along the edges from the table saw.

Step 4: Assembling the Tree

When all the parts were ready, I assembled the tree structure, clamping the top onto the pipe with the screw, and dropping the bottom of the pipe into the hole in the base.

My wife and I strung the two light strings at the same time, working together on opposite sides of the light-tree. We pulled just enough tension as we went so that the pipe stayed vertical. It is important to string both sides of the tree at the same time, as the pipe, plywood and plastic top are not strong enough to support the strain of being pulled from only one side.

We started ½ way around from each other, bottom to top, then to the adjacent notch, top to bottom. Details of the way the light strings fit into the notches are in the photos.

The light strings each had some left over, which we just stuffed under the base. This step took less than 15 minutes. After the light strings had settled for some hours and relaxed to their final length, we went around the light-tree again making small tension adjustments to back to vertical. Mostly just pulling a bit at the bottom of a run, and folding the cord under the base.

Since the strings we used each had an outlet at the far end, we were able to plug the head of one string into the tail of the other. This gave us just the head of the first string to plug into the wall.

Step 5: Making It Look Like a Christmas Tree

My wife turned the light tree into a Christmas Tree, by decorating with Amazon gift bags, some containing actual gifts. My wife also suggested that I take out a corn husk tree angel we had bought some years back and make that the finishing touch on the top of it all.

Step 6: Improvement

Christmas Light Tree finished, Not quite.
I ended up extracting 100 colored lamps from other light strings, and replacing every other one of the white lamps on the light-tree with those to make the tree more festive.

After I powered it up, I discovered that many of the replacements were blinking lamps which really animated the tree. See the attached video.