On my previous visit to SP Road (I had mentioned SP Road in this post), I had bought a large aluminium mug, hoping to use that as a lamp shade. I bought some castor wheels at a local hardware store, to try and add a swivel feature to the lamp shade, which I hoped to achieve with the caster wheel mechanism. This was after a fruitless search for lamp parts in local shops and online. I realised that I will either have to settle for what I am lucky to find, or improvise in some way to achieve the desired result.
I drilled holes in the base of the aluminium mug and attached the caster wheel mechanism to it with M3 bolts and nuts (minus the wheel itself). Where the wheel had been, was a slot into which I secured the end of the tilting arm, once again using nuts and bolts. This apparatus did not work as I had hoped, because the weight of the aluminium mug was centered at its handle and I could not get it to swivel as required (with no counter weight to help balance it). The swivel mechanism was too loose, which I tried to remedy by filling the gaps with a layer of Blue Tack, but that didn’t work either.
The tilting arm was attached to the main vertical body of the lamp using a hex bolt and wing nut, which could be tightened to hold the arm in position. However, given the weight of the aluminium mug, balancing this arm was a real nightmare, and I had to recall all of my school physics lessons about levers, fulcrums and equilibrium. I am condensing here what happened over the span of several frustrating days that I spent trying to get the arm to stay in different positions without support. I also tried using springs from my desk lamp to rig up a balanced arm mechanism but that too failed.
I ditched the caster wheel mechanism and tried to fix the aluminium mug directly to the wooden arm, without the swivel function, but getting the arm to balance with the weight of the mug at one end was still a problem. In the end, I decided to look for a lamp shade that weighed less, and this is what I used- an origami paper shade that was much lighter and diffused the light well.
The lamp once fully assembled was quite tall, and since the base was too narrow, stability was an issue- it could easily topple to the left or right. The base needed cross pieces at the front and rear ends that would prevent the lamp from toppling to either side. I added a piece at the rear first, using a T-lap joint.
I liked how it looked and it worked fine in terms of making the lamp stable, so I dropped the idea of adding a similar piece at the front end. I also liked the gentle slope in the base, as seen in this pic.
I sanded the pine wood starting with 80 grit and went up to 320 grit to get a smooth finish. I chamfered all the corners slightly as I liked how that looked, but this detail is visible only up close. Might make it more pronounced on a future design 🙂