[TowerTalk] 2" OD Long Masts

[Jim Thomson]

Date: Tue, 26 Aug 2014 08:47:33 -0700
From: Grant Saviers <grants2 at pacbell.net>
To: "john at kk9a.com" <john at kk9a.com>, towertalk at contesting.com
Subject: Re: [TowerTalk] [Bulk] Re:  2" OD Long Masts

Much cheaper than 4130 is the "1026" alloy A513  72,000psi yield.  I see 
onlinemetals.com has some 0.120" wall x 2.25" od which would make a 
great sleeve for 2" masts.  They will get full lengths if you ask as 
they are owned by Thyssen-Krupp or go direct to a service center.

Grant KZ1W

##  1026 is DOM.... drawn over mandrel.   It comes in any where from 72 ksi...
all the way up to 89 ksi. 

##  he probably has a 2 inch bearing setup on his tower......so a 2.5 inch OD 
sleeve would be hard to implement.   He would be better off to just use an inner sleeve,
that just slides in..with minimal slop.   Something in the range of .1875 to .250 thick. 

## I would suggest running all of this through the free arrl  mast software 1st.   Then u 
know exactly what you are dealing with.   I suspect you would only have to
re-enforce the lower portion of the mast... like from the rotor..... to about  .666
the length of the mast.   The last few feet at the very top would not have to be 
re-enforced.  


Jim   VE7RF