Not sure why all this effort for 15 or 20 feet of simple mast. These guys have
simple, portable style mast products
https://www.penningerradio.com/product-category/tipper-systems/
<https://www.penningerradio.com/product-category/tipper-systems/>
Chris
KF7P
> On Nov 11, 2020, at 5:56 PM, jimlux <jimlux@earthlink.net> wrote:
>
> On 11/11/20 4:00 PM, Grant Saviers wrote:
>> A quick look at Industrial Metal supply shows they have 0.058" wall tube so
>> sizes 1/8" different in od will telescope. (if not damaged)
>> Onlinemetals.com is also stocking 0.058 and 0.120 wall so for the latter,
>> 1/4" different in od will telescope.
>> yagimech software from DX eng can yield a good feel for the wind strength
>> and one can sleeve tubes once or twice (doable in yagimech) and the strength
>> directly adds (only true for round and square tubes). Always lather up the
>> overlap with Penetrox if you ever want to get tubes apart.
>> Of course increasing diameter wins over more wall thickness per lb of Al.
>> Grant KZ1W
>> On 11/11/2020 15:30, jimlux wrote:
>>> On 11/11/20 2:51 PM, john@kk9a.com wrote:
>>>> Correct , there is a lot of tolerance on extruded tubing and it will likely
>>>> require machining to fit together.
>>>>
>>>> John KK9A
>>>>
>>>> Ron Gorski ron-n9au wrote:
>>>>
>>>> No. The 1-1/4 inner tube will not necessarily fit inside the 1-1/2 in tube
>>>> because of nominal manufacturing tolerances.
>>>> Ron N9AU
>>>>
>>>
>>>
>>> Have you looked at using Unistrut (actually generically called "strut
>>> channel") it's pretty stiff, and a 10 foot length of the standard 1 5/8"x1
>>> 5/8" in galvanized steel is about $30. Aluminum is about $55.
>>>
>>>
>>> It's kind of like erector set for adults.
>>>
>>> There's all manner of clamps and brackets you can get for it to bolt
>>> equipment to the struts.
>>>
>>> There's a smaller size unistrut (low profile) which is less expensive
>>> (about 60%)
>>>
>>> ________
>
>
>
>
> Unless there's a specific need for it to look continuous, I'd just bolt the
> two with a "lap joint". You don't need extreme strength - the mounting plate
> under the tire will fail before the tubing will, because of the leverage.
> Figure 30 mi/hr max.
>
> (By the way, I see lots of RVs with flagpoles at the beach that are
> substantially more than 20 ft)
>
>
> Two bolts and two tubes overlapped.. ASCII art to follow
>
>
> ------------------
> | |
> -------------------
>
> If you're clever you could use one bolt, and then a couple ratchet straps on
> either side of the bolt to hold it straight. Put the bolt hole 12" from the
> end. Stowed, it's 10 feet long, with the bolt, and the ratchet straps holding
> it to wherever you're stowing it.
>
> -------------------
> |
> -------------------
>
> Get to where you are, unfold it
>
> -------------------
> |
> -------------------
>
> Put one ratchet strap around the pair near the end (and 2' from the end of
> the other one).
>
> Attach antenna, raise mast, done.
>
> If the cost isn't excessive, I'd seriously look at the Unistrut - having
> square sides and holes makes it easy to bolt stuff to it (rotator, antenna)
> without having to use U bolts or clamps, etc.
>
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