Keith Morehouse - WB9TIY wrote:
>
> Jack Ray wrote:
> >
> > I spent many years in the electrical supply business, and EMT > Electrical
> > Metalic Tubing is just that, TUBING.
>
> Jack, you're right, of course. Use that stuff to pull the 3 phase
> through for the big CONTEST amp. Keep it off the towers.
>
> BUT.....
>
> The 4130 Chrome-Moly 2.5" 3/8" wall I'm gonna buy for the big tower is
> called TUBING also. "Pipe" is designed to have "stuff" flow inside it,
> the name "Tubing" can apply to material used for OTHER mechanical
> purposes (like holding up those stack arrays ...) !
>
> Cheers.
>
> ---------------------------###-----------------------------
> PROBE ELECTRONICS 100 Higgins Road, Park Ridge IL 60068 USA
> Keith J. Morehouse / WB9TIY / Society of Midwest Contesters
> 847-696-2828 FAX: 847-698-2045 e-mail: blckhole@ripco.com
> ---------------------------###-----------------------------
>
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Something to remember about tubing and pipe.
Tubing is measured O.D. and pipe is measured I.D. up to 8 inches or
there abouts. A one and a half inch pipe will measure 1.5 inside and
1.9 outside. A two inch piece of tubing will be 2.0 outside. Also a
piece of chrome-moly tubing with a .058 wall, will be just as strong
as a piece of mild steel tubing with a .125 wall thickness. So if you
use .125 wall chrome-moly you can see why it is stronger. One more
thing, if it's sch 40 or 80, its Pipe.
I can't afford chrome-moly. I used a piece of inch and a half galv. pipe
with a one inch piece inside of it. I made 3 sleves to go on the one inch
pipe to make it fit tight inside the inch and a half. I placed one at each
end and one in the middle of the one inch pipe. I welded them in place and
drilled half inch holes in the inch and a half pipe at the correct places.
I then put the one inch inside the one and a half and plug weled the holes.
I have been using it for 3 years and all is fine but not a lot of wind
load on it. I also put an expandable freeze plug in the top to stop
the rain water from getting between them. Cost, just my time as I work in
a steel shop.
Hope I didn't put ya all to sleep.
Bill, KB3AUG
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