Cassiopeia Observatory - POD Roller Desk

POD Roller Desk
Posted: 29 February 2012
Updated: 20 June 2024

I have been thinking about making a POD wall desk for about a year, but I never finalized the design. My concept was that the desk would rest on the top of the POD wall but move as the dome was rotated. Another POD owner (Rick Allnutt) built a similar but simpler fixed desk for his POD. That prompted me to get more serious about my design. As I did while designing my "eyepiece tray", I layed out the design of the desk on grid paper:

Desk shelf design (top):

Desk shelf (side view):

I didn't make a cardboard mockup this time as the final design would depend on the size of the casters used to hold the desk to the wall. After I drew the above side view, I realized that this design would not work without modification. The POD wall with the door does not match the contour of the five bay walls. This meant that the desk would likely pivot on the dome wheels as pressure is applied to the desk (like when writing notes). So, I had to redesign the mounting concept. I originally wanted the desk to have a slight tilt to make writing easy. But that would not work without adding additional support (and weight) to the desk. I have (for now) decided to go with a level desk. The second design change I made was to shift the caster locations to better match the POD wall interior and exterior surfaces. A third change was to add a small lip to the left, right, and top edges of the desk. There was already a lip at the bottom to keep papers and a pen from sliding off the desk. Here are the modified drawings:

Desk shelf new design (top):

Desk shelf (new side view):

My next step was to acquire the various pieces by making a trip to a local Home Depot. They had everything I needed; costs were $41 for the casters, mounting brackets, wood, bolts, nuts, and washers. Here are the pieces:

I assembled one of the caster mounting brackets for a form and function test:

I took this to the POD to verify the placement of the caster wheel against the POD wall. It looked like it should work.

Inside view:

Outside view:

After cutting the wood for the desk and attaching the side lips, I placed the desk on the wall. I then held an inside wheel to mark where holes for the mounting brackets would be drilled. I repeated that for the other inside wheel. I noticed that I needed to change the orientation of the brackets from what the design shows, otherwise there was a chance of a bolt being too close to the edge of the desk. Once the inside wheels were attached, I again placed the desk on the wall, held the outside wheels, and marked the hole locations. I confirmed the distance between the wheels matched the width of the POD wall (4-7/16"). This photo shows the casters mounted on the bottom of the desk:

One other modification I had to make was to shorten the 1-1/4" bolts used to hold the brackets to the desk. That was necessary to keep the bolts from rubbing on the top of the wall. I also shortened some of the bolts holding the desk lips.

With all the wheels attached, it was time for a fit and function test. It worked! The desk fit snuggly on the wall and would move as the dome was rotated. Here are some photos:

There was some tendency for the desk to tilt inward into the POD. I decided that adding a set of casters above the existing casters might keep the tilt from happening. So, another trip to the hardware store to get four more small casters ($9). Here are photos of the double casters:

Inside view:

Outside view:

The inside casters are positioned differently than the outside casters. That was not planned; that was the only way they worked without making some positional adjustments of the brackets, which would have entailed more measuring and drilling.

Did the extra casters help prevent the unwanted tilting? YOU BET! No tilting tendency and the desk seems very secure on the POD wall.

This project took a little over eight hours to complete, including construction, photography, testing, redesigning, and more testing. I look forward to using it on my next night session in the Cassiopeia Observatory SkyShed POD.

Update 20 June 2024

As seen in the photos below, I reversed the bolts so they do not stick out. I had previously cut these bolts to be much shorter. I also tightened up all the bolts on the desk since they had loosened up during the past 12 years of use during each session in the observatory.

The POD Roller Desk looks nicer now.

Comments

Go to the previous report.

Return to the Cassiopeia Observatory Welcome Page.