My suggestion was to consider a 3" x 1/4 wall 1026 instead of a 2" Chrome
Moly mast. I suspect that 3" 1026 is stronger than 2" 4130 (I don't have a
mast calculator handy) and it is easier to climb. I purchased a 3" 1026 DOM
from steel company and had it galvanized. My costs were significantly less
Array Solutions plus did not want their odd 2 7/8 size. At that time DX
Engineering did not sell masts and no one else sold a 3" mast so making one
was my only option.
John KK9A
To: <towertalk@contesting.com>
Subject: [TowerTalk] 2 inch Chrome Moly mast needed
From: "Jim Thomson" <jim.thom@telus.net>
Date: Thu, 7 Apr 2016 14:59:51 -0700
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Date: Thu, 7 Apr 2016 06:34:30 -0400
From: "john@kk9a.com" <john@kk9a.com>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] 2 inch Chrome Moly mast needed
If you really need that much strength, consider a 3" 1026 DOM mast. Your
tower is not made of chrome moly why does your mast need to be? I cannot
imagine why 2" is the standard. Do you really want to climb 15 feet of 2"
tubing?
John KK9A
## 2 inch OD x .375 chromolly tubing weighs the same as 3 inch OD x .25
chromolly tubing..and they both cost the same. Aprx 7 lbs per foot.
## The strongest thing up there should be the mast, bar none. Have you
ever
seen a mast failure ? Total gong show. Imagine a mast, folded at 90 degs,
right
above the top of the tower...with yagis mounted on it. Now what are you
gonna
do ?
Tower stays intact of course, but the folded mast is a complete mess.
## Typ 1026 DOM masts are 2.875 OD x .25 wall, also galvanized. Yield
strength on the version that
array solutions sells is 87 ksi. The CM version sold by dx eng is aprx
107
ksi. The problem with
2.875 od material is getting mating bearings for it. Also a lot of rotor
mast
clamps are for 3 inch,
and would have to be shimmed. kurt andrress will custom make a 2.875 mast
clamp for stuff
like PP rotors or OR-2800 etc, etc.
## do it right the 1st time. Then install mast steps so you can safely
climb
the mast.
Pay once, cry once..but do it right.
## Run the mast calcs for 87 ksi 1026 DOM in a 2.875 x .25 wall.....VS
107-115 ksi 4130 CM in a 3.00 x .25 wall...and you will be amazed.
Jim VE7RF
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