Like most families we do our computing on laptops or tablets and no longer have a computer desk with a desktop computer. Because of this, we had two office chairs that had basically been banished to a dark corner. A few months ago, I decided to remove the back of one of them and use it as a rolling laptop stand. I used it this way for several months and while it worked decent, the arms of the chair were a bit cumbersome, there was no place for a mouse, and it was a too low to get my legs under. I decided to fix all that. Keep reading and see how I did it.
Step 1: Disassemble the chair
Disassembling the chair is pretty straight forward. There are a few screws that hold the base to the bottom of the seat.
As mentioned earlier, this particular chair, even when fully elevated was not high enough for me to sit on the couch and still get my legs under. It's very possible that your office chair may be taller or may not need any height added, in which case, skip the next step. Otherwise read on.
Step 2: Add some height
I knew I would be using this while sitting on the same couch the majority of the time, but if I wanted to use it at different couch or chair that sat higher, I'd want to maintain the adjustability of the stand. I made sure that the chair was adjusted to it's lowest setting before proceeding.
The chair lift cylinder is press-fit into the wheeled base. It can easily be removed with a sharp blow from a plastic mallet. Once the lift cylinder is removed, you can see that the bottom of the cylinder is tapered to provide a snug fit into the base. Looking around my garage, I found a short piece of 1-1/2" Schedule 40 PVC that fit pretty snug in the base. With the PVC dry fitted into the base, I took the base and the lift cylinder back to the couch to determine how much height I needed to add. I ended up cutting the PVC to 11-1/2".
The PVC is approximately the same outer diameter as the lift cylinder, but PVC is easy to re-shape once it's warm. I used a heat gun, but the same results can be achieved with a propane torch, camp fire, barbeque grill, etc. The big concern is not getting the PVC hot enough to burn or release toxic fumes. Probably the safest method is to dip the end in boiling water until it has reached a temperature for it to be soft and pliable.
Regardless of how you do it, soften the end of the PVC and press it over the bottom end of the lift cylinder. Pay attention to the alignment of the cylinder and the PVC. Ideally, you want them to be perfectly inline with each other.
Note: Since this was originally a chair, the platform that the seat bolts to is made to have a rear leaning cant (i.e. - the back of the chair sits slightly lower than the front). Because of this, when the whole assembly is turned upside down, the lift cylinder is not perfectly vertical. If I were to do this over, I would first level and mount the top as shown in the next step and then come back to this step to complete the height modification.
For the bottom of the PVC where it fits into the base, you'll probably have a little bit of play. This is because the PVC is the same diameter all the way up, whereas the lift cylinder was tapered to fit the taper of the base. To remedy this, I heated a small section of the pipe ~1" from the bottom. Once it was soft, I inserted the PVC into the base and applied enough pressure for the PVC to "flare" out to match the taper of the base. Hold things steady (and plumb) until the PVC has cooled enough to hold its shape.
Step 3: Add the top
For the top of this stand, I used an old smooth faced cabinet door that I found in the garbage. The door was basically square, so I cut it to the size I needed. On the underside of the cabinet door, I found the center by drawing a line from corner to corner. I then offset the center point in both directions to match the bolt hole spacing. I dug through my hardware bin and found some suitable wood screws and predrilled the holes. Tip: keep hardware from everything!!! If you replace a light fixture - strip all hardware from the fixture before throwing the fixture away. Same goes for cheap particle board furniture - remove and keep all those specialty type brackets and screws before tossing it out, because you never know when it'll save you a trip to the hardware store.
As mentioned earlier, for ergonomic reasons, the seat platform is manufactured so that it slopes to the rear. You can see in the 4th photo that the piece that connects the round tube to the seat platform is a trapezoid. The edges that connect the tube are not parallel with the edge that is welded to the bottom of the platform. Since I want the top surface of this to be level, I placed a stack of washers under the low side to help level it up. Once leveled up I screwed the seat platform to the underside of the door, hand tightening the screws to prevent stripping the holes.
Step 4: Finished
I sanded the cabinet door with a small palm sander and wiped it down. It appears that this door was given a "wood grain" finish by some paint method. The lighter color you see is a solid shade of pale yellow. The original grain pattern was achieved by a 'false graining finishing technique'. I like the look of the tattered board.
I'm really happy with how this turned out. It provides a nice adjustable work surface that can easily be rolled out of the way.
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