A Table Lamp that Tips

Tipped to the Right.

Why a lamp that tips?   

Not for momentary joy or by a design mistake. With a way to keep the lamp leaning over at least a few obvious benefits become available.  Park the lamp on a corner of a table, then let it tip toward the middle to better illuminate the table surface.   Have kids that like to play on the floor?  Tip the lamp out to better illuminate the floor beside the table.  Using one or more 1"d steel balls and a rim of dished pockets you can move the Center Of Gravity around so the lamp will stay leaned in the direction the ball(s) are positioned at. Maximum lean angle is 12.5 degrees. 

Maximum Lean

This design consists of three wood parts.  A hub that the light hardware connects to. A simple center post. Lastly a domed base. Simple. Three parts. The lamp can tip but won't fall over. The base is a larger mimic of the top hub. The power cord runs up through the center post which is done in two halves. It exits the side of the base which is also cut in top and bottom halves.  The 1" steel balls were ordered from the jungle store, along with the 12mm threaded brass balls.  I used two halves each for the post and base to make it easy to route the power cable through. Base is 2.25" thick and the center post large diameter is 1.5". 

Almost Straight Up

A 12mm diameter brass ball screws down onto the harp. The shade ring with a 3/8" diameter hole rests on it and stays level no matter how far the lamp tips.  

I used the modelling tools in Aspire to make the pockets for the 1" steel ball on the curved surface of the base top. The moulding toolpath was used to shape all the other parts. Nine pockets evenly spaced around the perimeter allow just 3 steel balls to vary how far and in which direction the lamp tips.  

Undecided

This project, as many do, threw a few challenges to me when making the parts.  2-sided CNC projects must be perfectly aligned when flipped over.  Even when I think I have that challenge solved it is worth verifying alignment before each new cut. 

First try making the bottom of the base proved my design theory was wrong.  The curve was so flat the weight of the base itself was so heavy it wouldn't tip even with the steel balls all on one side.  

Second try I recut the bottom dome using 1/2 the previous radius.  It still was harder to rock the base than I want it to be.  Adding the light hardware, bulb, and shade might have made a difference so I added them to check. Testing proved the weight of the light hardware and shade weren't enough to make a difference.   

I had a cherry block that was large enough and thick enough to make a new base bottom. 1+5/16" thick.  Third try did indeed tip with the steel balls rather easily.   A bottom dome with close to a 6" radius center works well. 

This concludes my chase to see if this crazy idea works. I'll throw some maple stain and a top finish on the parts next time I have my finish table set up.   

Comments welcomed and appreciated. 

4D

 

A Delicate Tea Table

Hard Maple

This maple tea table was inspired by a metal version I found on the web.  

I remembered I had a maple panel.  It was a bit thicker than 3/4".  19" x 14".  Room enough to cut four 3" strips from that were 19" long. Glued them together to make a 3" x 3" x 19" block I used to make the center post from:

Center post 

Mounted on my radial axis. First step was to turn the square block into a 3" cylinder. 

18 inches of 3"d cylinder

Then the roughing cut, which pointed out a few flaws in my setup. The square section left next to the 3-jaw chuck didn't care to run into the router chuck as it created a burning smell and left the router chuck black with carbon. 

I made a finish pass down the cylinder to cut the desired shape.  A few visible flaws left from the roughing cut that went haywire. I took the post from the CNC out to my garage lathe to clean up and sand. 

For the base I glued up some maple boards.  They were a bit thinner than 1.5" thick. When the glue was dry I scraped off what squeezed out, then used my drum sander to clean off and flatten both sides.

Uniformly flat, clamped to my CNC bridges, and getting the bottom cove cut out.

Cove cut.  Almost done.

Board flipped over, new file loaded, and the top surface was cut. Next to the bandsaw to cut off the corners.  After that a trip to my trim router table to flush trim the bottom edge, then round over the bottom edge just a little (1/8"r). 

Base trimmed and cleaned up.  Post trying it on for size.

A good snug fit. 

Next came the top for this table. A thin edge is desired. It would help the structure to be thicker in the middle where the post connects.  Made an intermediate plate that glues and screws to the post, but then can be screwed to the bottom of the table top.  I ordered some 3/4" thick maple strips I can glue up to make the top from. 

Maple to make the top arrived. Strips 2" wide, 3/4" thick, and 16" long. The strips were square and smooth and  ready to glue together. 

Some advice to minimize the chance of bowing after the slats are glued up, is to alternate the end grain curves on each piece. 

Once all the strip are glued together and the surface cleaned up a trip or two through my drum sander smoothed out any offsets and made both sides uniformly parallel to each other. 

Next was clamping the panel down to my CNC and cutting the bottom contour.  The hub was cut first.  Left on the CNC to check that the center post top tenon does fit in the mortise in the center.  Wisely done, as it didn't fit the first time tried.  A new CNC file was made and run to cut the mortise wider.  With fit verified the contour shape was cut.  Then the part was remove from the CNC and cut free from the starting block using my bandsaw. 

The top underside shape took the longest to cut and created a beautiful huge mess of fine maple chips.  

The only deficiency of this design is that from above where most will see it the contours under the top are not visible.

Simple thin edge.

This table will get a maple stain to even out the color of all the board strips. I don't drink tea, so am not sure where this table will end up.  😉

As I study the aesthetic details, the simple top seems naked compared to the post and base below.  My first addition is a 30 degree bevel around the perimeter.  To accomplish that required a fixture with bearings to add to my trim router table fence.

Bearings to keep the edge from getting too close to the bit. 

No room for a bearing to run on the edge. 

Beveled edge.

Comments welcomed and Encouraged!

4D