[Towertalk] Tower Buidling 201

[Bill Coleman]

On 8/31/02 1:27 PM, Stan & Patricia Griffiths at w7ni@easystreet.com 
wrote:

>Install the house bracket before you pour the base concrete.  This way, you
>can move the tower base slightly to get it perfectly vertical, and THEN pour
>the concrete.  This is much easier than trying to get the house bracket in
>exactly the right place after the base is set in concrete.

Sorry for the late reply, but here's what I did.

1) Temporary mounted a house bracket at 9 feet to the house.

2) Built a 2' by 2' (interior) frame out of 2x4s. the frame is the top 
form for the tower base.

3) mounted a centering string on the frame, and another string just 
behind where the legs should go. This gave me the exact center of the 
face nearest the house.

4) used a plumb bob mounted on the center of the house bracket to locate 
the exact position of the frame.

5) leveled off the surface of the ground to locate the frame.

6) dug the hole for the base with the frame in place. (~1800 lbs of 
earth, all with a shovel and a post-hole digger)

7) put 4-6" gravel in hole.

8) put rebar cage in hole.

9) mounted two sections together. Dropped them into the hole, inside the 
rebar cage.

10) connect sections to temporary bracket.

11) used plumb bob to get the tower vertical.

12) got pre-pour inspection by county.

13) pour concrete. wait 7 days for cure.

So, at this point, the base is in the right place, the first two sections 
are vertical, but the bracket is too low.

14) stack another section of tower.

15) mount the lower bracket (18 feet) to the TOWER first, in order to 
locate it on the right place on the wall. Then fasten to the wall.

16) remove temporary bracket at 9 feet.

17) stack another section of tower.

18) repeat process by mounting top bracket (25.5 feet) to TOWER first, 
then fasten to wall.

Note that HB25 brackets allow a little bit of adjustment along the face 
of the wall, but there is little or no fine adjustment coming out of the 
face of the wall. 

Oh, and I used a plumb bob before I stacked the top section to make sure 
the tower was true. I made a job out of a piece of wood and nails that 
would fit over the horizonal braces of the tower section and put the 'bob 
right in the middle of the tower.



Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@arrl.net
Quote: "Not within a thousand years will man ever fly!"
            -- Wilbur Wright, 1901