December 12, 2010

I'm back with an update and its only been a month - instead of three months like the last one. We've had two very productive Saturdays since then - on December 5th John and I worked together and then this past Saturday Kristin AND Matt joined John and myself. We completed a lot and are getting very close to having the crew come in to put up the roof.

December 5th was dedicated entirely to working on the steel for the east wall rail supports. As usual we started about 9 AM; the day was pretty cool with temps in the low 60s, breezy and partly cloudy. In the picture below John is on our temporary work platform measuring for drill holes to attach one of our plate supports:



In the picture below John is cutting through the roof into the warm room area. The support beam that will go here will have two vertical plates, inside and outside, and secured with steel bolts through the cement blocks.


The steel beam in front of John's face is the beam to be supported and has not yet been secured in place.

The support piece needs to be fabricated to reduce the span of the horizontal support beam from about 15 feet (the distance from the last direct roof attachment to the support pier) to 7 1/2 feet. Below John is welding the saddle piece onto one of the vertical plates of the support piece.




One of the things we need to do is to grind the end of each beam into a bevel so that we will have a good surface to weld the beams end to end. In the photo below John is doing exactly that but to the beam on the roof. Usually we do that at ground level but we simply forgot and lifted this beam to the roof a bit early.


The partially complete support plate is put in position and welded to the horizontal beam as shown below. Note that the inside vertical plate is not yet attached. There is also a vise-like clamp attached to the plate. That is used to serve as an electrical conductor to the welding machine to complete the circuit and permit the weld to occur:


Before we weld the horizontal beam/support plate to either the observatory wall, the other beam resting on the forward part of the building, or to the support pier, we have to make sure the beam is level. Since the north end of the beam rests on the top of the support pier, we can adjust the end of the beam height with the adjustment bolts at the bottom of the pier that are sunk into the cement footing. A six foot magnetic steel level is attached to the pier to ensure that any height change we make will be corrected so there is no change in the verticality of the pier. John is making that height adjustment in the picture below:

When we are absolutely finished here, the steel will receive additional primer coat and a cap of cement will fill in the narrow space under the steel pier.

One last thing to check is that the beam is straight and it is laying absolutely flat. In the photo below you can see that the beams are lined up in length as perfect as a laser level can make it, the beam is completely flat, and the measured difference in height over the 38 feet of total beam length is only 50/10,000 of an inch - far beyond the tolerances necessary.

We decided to add even more support at this point that was not in our original design. The photo below shows John proudly showing off his work: a twelve foot 2 X 6 beam in place with temporary clamps that was shortly welded vertically to the bottom of the horizontal beam. Additionally, at the steel pier, an L-bracket was welded to the upright and the new beam sits on it and is welded to it, the beam above it, and the pier.

The red box in the foreground of the above picture is the actual 20 amp welder.

The next step was to weld the two beams to the support piece fabricated earlier. Here's a photo of John performing the weld while standing on the platform. Plus you can see the entire east wall's rail support structure with all the support plates and beams in place:




Here's a closer shot of John's welding technique:

That pretty much wrapped up that day's work.

This past Saturday we had the biggest work crew at the observatory since we started. Kristin and Matt joined us for a day in the country and some fun. We apportioned the work so that Kristin would continue the second primer coat everywhere, I would apply primer to all of the top metal wall supports, Matt would do some excavation (to get ahead of schedule by about a year) plus he would help John with the most important work of all - completing the rail support work on the west wall, similar to what he completed the week before.

Matt had not been to the high desert before so this was new to him. The day was perfect - mid-70s, light breeze, and bright sun. Kristin tackled the second primer coat on the outside of the observatory. In this picture, she actually excavated a bit below grade so that she could complete the lowest course of cement blocks. Once the paint dried, she shoveled the dirt back into the trench:

Matt went ahead and dug four sizable holes in the rotten granite that underlays our site. His strength had us in awe. When John and I dug holes in the same spot for the two pier footings, it took us weeks using a jack hammer - Matt dug four holes with just a pick and a shovel - NO jackhammer - and transported 20 barrels of dirt to the front of our driveway by lunchtime!! Here's Matt digging the first hole:

Here he is at the far end of the driveway, raking the barreled dirt to widen our driveway:

Here's a shot of Matt and John showing their appreciation to me when I took time off my hard work to perform the duties of the observatory historian:

Once Kristin finished with the lower course of the outside wall, she came inside to the observing area and put the second coat on all four of the inside observing area walls:

The final horizontal beam for the west wall needed to be cut to size and the ends squared off prior to beveling. Here is John and Matt cutting an 18 foot beam to size - not an easy task. This cut required almost five minutes to complete:

It was about this time that we broke for a short lunch - what a morning's worth of work!

With lunch over, John and Matt went back to the steel work and Kristin and I teamed up on putting the second primer coat on the outside walls. We painted all but the east wall in less than two hours (much easier than when the first coat was applied); we left the east wall to another day because it was in the shade and we felt the wall had already cooled more than we felt comfortable with painting.

Kristin continued priming the stairwell to the observing area. Matt took a break from his heavy duty to help her:

While fabricating the support plates, bolt holes need to be drilled into the plates. Here's a photo of John and myself working on a drill press making those holes:

In terms of the steel work for the west wall, John did much the same work as I described above from the previous week so I've simply posted some photos following with no explanation:

Here we are, end of the day, much more accomplished than we thought, so here's a cute photo of our recently married couple, being re-united after a day of drudgery and serfdom:



Actually, I wanted to show the holes that Matt had dug earlier in the day and this was the only picture showing them.

We are approaching the end of this construction project. A few more days of steel work assembling the actual rails on top of what John has installed over the last two weeks and we can call in the roofing crew, headed by our good friend Gary. If you remember, Gary fabricated the roof structure in several sections in his driveway last July. Once the rails are in, he will bring in a crew of about four workers and spend no more than two days assembling the roof in place. Hopefully, that will occur in the next two months.

Have a great Holiday Season!