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![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEihJ3st6w-q4fDQYmum0-UNIFR6j7KUycx3JCVpmgLt6RBqOacK4E1dTV4w4ZCAjnPb4gCVJ6G4jUZ53n0evY6KYl23UCpfid0mushsvk8P1X0aa9ctoRDEHoGPkEZSYoaFanqiVNnkKw/s200/rise+and+fall+pier+2.jpg)
The pipes are only 3/4" larger than the 4"x4" pyramid posts.
A typical car scissors jack provides about 8" of travel and the load would be relatively light compared with a car. A hand crank on a wheel in place of the jack's fiddly drive rod arrangement would be beneficial for regular use. I also have to brace the pyramid lower down to stop the timber adapter from rocking.
So I might as well consider rise and fall in the design. I have a long length of 120mm square [4.7"x4.7"] alloy tube with 5mm wall. That would be idea for the piston movement and it is quite close to the 4" timber I am using. Far closer than my drawing would indicate! There would be enough tube to provide a little over 60cm or 2' lengths for four, rise and fall , "pistons." Perhaps that's not really enough for stability when raised by 1/3 their length?
Having wasted weeks playing with different pier ideas it seems I am going off on another wild tangent. Perhaps I should go with the five posts adapter and return to "rise and fall" later. By then I should have had a chance to make some serious progress elsewhere. My first ideas are not always the best solution and they usually need time to mature into a better form.
Here, scraps of timber are used to locate the concrete footings at the correct angle in the excavation. Each off-cut was removed as I tamped self-compacting sand down firmly around the block with a batten.
I decided I would tilt the concrete blocks to follow the line of the posts. My fuzzy theory being that there would be a spreading force between the pyramid's feet. Getting the lean correct involved a mirror laid on top of the block. By sighting down the sloping post I could see my own reflection. The brackets provide fine, height adjustment by means of a 12mm screw. Which may become useful over time.
Only experience will tell if I was wrong to use the footing blocks and brackets. The disturbed sand and gravel will soon settle after another day of my going mostly backwards and only a little forwards.
Click on any image for an enlargement.
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