14.4.18

Thickening and raising domes:

*
After four days of gales the wind has fallen light but it is drizzling lightly now and then. After cutting 40-odd braces I realised I was mistaken about them being reversible. So I had to mark L&R and cut one end the opposite miter angle. Fitting longer tilt stop screws to the DeWalt compound miter saw allows me to flip-flop the blade by 5° each way without needing to release anything. So it didn't take long to correct without changing the length of each strut.

I decided to cut down the strut dimensions to save some weight on the completed dome. 120 of anything soon adds up. Even the thin, off-cut strips weighed quite a bit.

By ripping the 20x90mm boards with the table saw blade tilted at 10° I get a pre-cut profile. The pile of sawdust is certainly building quickly.

I'm working inside the shed with the miter saw to avoid having to carry it in and out. It weighs far more than I care to manage at my age. The table saw is more manageable and much less awkward. I store it on the floor and sack truck it back and forth. Which leaves only one big lift up onto the B&D folding workbench. There is a DeWalt, hydraulically assisted, rise and fall bench. With wheels like a built-in sack truck but it's not exactly cheap! If it saves me from a back injury then it might be worth having.

Well, the hydraulic bench had an awful review so I gave up on that. Fortunately there is another bench, with handles and sturdy wheels. Designed to make transport easier over a building site without having to demount the table saw. The DE7200-XJ is cheaper and lighter too. There are several YT videos which indicate it is probably a much safer purchase than the rise and fall model.

Sunday 15th April found me still cutting and fitting vertical struts. I used a clamped stop on the miter saw to trim each strut to exactly the same length. This had the advantage that it forced the horizontal struts to become better aligned and horizontal. Though I had to unscrew several of them the overall accuracy wasn't too bad to start with. Some just needed the strut to be tapped home with the loaded plastic hammer before screwing it into place with 25mm [1"] csk stainless screws.

Rain stopped play just as I put the last screw into the last strut. The upper [third] tier was difficult to reach so I took the gores down to work on them one at a time. The skeleton is looking far more chunky now and should have remarkable resistance to wind and snow loads. But now I can't fit my spring clamps over the paired ribs and vertical braces. I'll try ratchet straps and friction when I need to erect the dome to work on it. A week of warm and sunny weather is forecast.

Next I'm going to use a rough disk on the angle grinder to trim the ribs neatly back to the level of the struts. The jigsaw I used to cut the flats on the ribs was pretty rough at times. I used a scribed guide line for each cut but the saw wandered a bit. 

Click on any image for an enlargement.
*

No comments: