For the requested A4S application, 6061-T6 tube would work, even making
one from sleeved DXEngineering 0.120" wall tube (which I suggested
privately). Cheap and UPS deliverable.
I had a TH7DX (2x an A4S load) on 22ft of 2" x 0.375 6061, 18ft above
the house bracketed Rohn 25, it survived 3 hurricanes in EMA. A bit
bendy when tilting over the tower, but plenty strong enough.
Another steel choice is A513 DOM, slightly less strong than 4130 but
much cheaper. Also more likely in stock.
Grant KZ1W
On 12/29/2019 04:53, john@kk9a.com wrote:
For a small Cushcraft tribander and 2m beam a Ø 3" 4130 mast may be a
little overkill:)
1026 DOM is a very good mast material, not all masts need to be chrome
molly. Even aluminum can work well and it requires no corrosion coating.
I had two Ø 2 1/2 aluminum masts at http://www.p40a.com and they held up
well in that tough environment.
John KK9A
From: Charles Gallo KG2V
Date: Sat, 28 Dec 2019 13:38:15 -0500
The problem with most sources is that shipping is the killer.
As someone said, under a certain length (108 inches aka 9ft) it can go UPS,
over, you are looking at truck.
What we call CrMo DOM mast is more commonly referred to as 4130 tube. If
you
have a ‘local’ steel supplier, there is a good chance they either have
it, or
can get it fairly easily, and you may be able to pick it up. (Assuming
you have
a truck), or they might be willing to do a delivery (expect to pay). If you
have a local machine shop, or user of steel, you might be able to sweet
talk
them into ordering the material on their next shipment, and the delivery
gets
lumped in. Hint, your 90-200 lbs of mast (3” .250 wall, about 7.75 lbs/ft,
smaller diameters less) doesn’t mean much when they are getting 3+ tons of
steel delivered.
--
73 de KG2V
Charlie
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