Well said, Chris. Actually, 1/2x4x4" angle is enough - works for a
HDX589 with 4x 1" bolts.;-) UST multi pass welds that custom bent
angle to their reinforced "T" base.
I've made said design base scaled down for 40' Tri-Ex crank up, and now
am working on one for an LM470. A turkey sandwich is a better deal even
with the holes drilled on my 5hp mill and steel cut on a horizontal
bandsaw. Everything needs to align after the welds cool and that takes
some skill. The reason I need to make the LM470 base is the garage
shop job for the prior owner made one badly out of square & flat & on
the light side structurally. NIMBY.
Relatively speaking the fab is straightforward and the engineering is
definitely not. I've done simple structures, and these aren't, but good
copies of the factory bases well executed with the proper materials
should/might be ok. Caveat emptor 'tho. For example Brian, how do you
know the factory plates are "mild steel" and also the grade of the rebar?
Grant KZ1W
On 6/9/2017 16:34 PM, EZ Rhino wrote:
In the amount of time it took you to type out this treatise, you could have
called Tashjian Towers, ordered a new base, and then still had time left over
to walk into the kitchen and make a nice turkey and swiss sandwich, and consume
said nutriment.
If you're still wanting to build your own, there is a no-weld solution that involves
anchor bolts set into the wet concrete during the pour, and a very large piece of
1/2" plate steel with holes drilled for the anchor bolts. Then another set of holes
are drilled for very large angle, like 3/4" thick, where one side of the angle bolts
into the base plate and the other side bolt to the tower.
By the time you're done trying to bore a dozen or more 3/4" diameter holes
through steel that thick, you're going to be wishing you had made the phone call and
eaten the sandwich above. Make the call, thank me later. :-)
Chris
KF7P
On Jun 9, 2017, at 15:50 , southbound suarez wrote:
Seems as if there's a huge proliferation of these towers out there. I'd dare
say probably record production compared to any other Ham/private consumer tower
if you exclude the 25G series.
That said,
Does anyone have any plans or instructions or essentially a how to recipe for
fabricating or securing this old Tri-Ex crankup tower to a foundation? Ideally
some specifications for specific material type selections (metallurgy) ,
size/thickness and retail sources for these materials? Welding requirement as
well as what design considerations or possible critical failures that a DYI guy
should be aware of?
I am well aware of and respect the fact that this is indeed a critical
application and that there exists some major risks including major liabilities.
The possibilities of a catastrophic failure places strong risks in the form of
severe property damage,; great bodily injury and possible death.
I believe in good conscious that I have a healthy respect of these facts.
While I am a very handy person with good mechanical apptitude and experience in
construction trades, I know enough that I am far from a proper mechanical
engineer. I have much to learn of actual loads , stresses and best
practices.... Experience and hardknocks does have some merit similiarly does
common sense (usually an oxymoron) especially judgement or understanding.
Obviously, "Rocket Science" can be applied to anything and make for great
efficiency, betterment and overall greater safety. (So much better the hit over miss
ratio)
I CAN APPRECIATE THE NUMBERS BEING CRUNCHED! BUT.....
When you look at the designed base of what this tower was shipped when purchased brand new and even
the same with what is being provided by manufacturer today? Engineering practices and formulations
set aside... The Base appears as if it is just three 2" wide by 12" long 3/8" mild
steel plates. The plates tab welded with full bead along there length to about a 24" length of
rebar. Each plate/rebar upright are then welded to a triangular formed rebar horizontal member.
This is then conventionally tie wrapped to the structual rebar concrete reinforcement... Doesnt
seem so exotic or rocket science to me???
I do understand that there might be some subtle but important things not so
obvious. I consider that there exsists certain forms of weldable rebar and that
heat will anneal steel. Especially mild ductile steel plates. Certain critical
welds must adhere to specific standards...
I fully respect the reasoning for good uniform codes and standards. I
understand about professional peer review and adoption of professional
standards.....
Maybe to everyones benefit we can get a good and educational discussion going
on here. Maybe there's some esteemed slide ruler type that could give the class
a presentation on some of the basic physics and caculations. For those
industrial insiders that govern over the art and practices, how about a quick
review of the most pertinent and applicable sections of the numerous plethora
of codes and overlapping professional disciplines in which contribute to the
structure of radio amatuers affection. AND..........
Selfishly and ultimately educate me on how to best construct/obtain/procure the basis
(or bases) <pun> for constructing my own foundation to bolt my second hand W-51
tower into an upright position that is useful (safe) and reliable all on my own.....
MY SPECIFICS ....
This will be a non-inspected install with at least 100ft setback in all
directions. No structures or pathways in peril .... simply a private install on
private land with minimal intrusion by local governing officials...
None the less, I do wish to meet or exceed proper building standards.
Thanks for reading my lengthy and intial posting as a new member of your
excellent and esoteric community.
73,
Brian K6LPM
Brian
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