A couple of notes after marking and drilling the top plate.
(1) I have an older Rohn top. It is slightly tapered with a small round plate
on top. Some of you may remember the old Cushcraft catalog which displayed all
their antennas on just such a top. The center hole in the top plate is small
enough that none of my Thrust Bearing holes were in the center hole.
(2) Unless you just went out and bought yourself a new set drill bits, go to
Lowe's, the other HIW or your favorite tool distributor and buy yourself a new
drill bit, preferably one of the Kobalt or other high-end type. The metal on
my top is HARD. I knew it when I rapped the center punch with a normal shot and
did not even leave a mark other than in the Painter's Tape. After center
punching the top, drilling went well, albeit slowly. I had to enlarge one hole
a bit as my marking may have been just a bit off.
(3) The bearing turns at least as well as the TB-3 it is replacing which was
broken when inspected it. I still have a bit to get and do before the Bucket
Truck comes and I can finish this project.
Clint - W5CPT
----- Original Message -----
From: Clint Talmadge
To: R Atkins ; towertalk@contesting.com
Sent: Friday, July 13, 2007 8:39 AM
Subject: Re: [TowerTalk] Yaesu GS-065 Thrust Bearing 25G installation
helpneeded
Odd that this post should come now. I was on my way to the garage where I
have my 25G top section laid out across the bed of my pickup to redrill the top
for my Yaesu GS-065 thrust bearing. Here is my plan.
Use masking tape to layout the pattern.
Scribe the center line between opposing pre-drilled (TB-3) holes I can see
though the Blue Painters tape where the holes are so getting it centered was
easy.
>From the intersection of the two lines (center of the top plate mast hole)
measure half of the 85 mm center to center distance as indicated in the Layout
Drawing for each of the 4 holes
Mark and drill using the center line I scribed and the distance I measured.
I will let you know if I run into any other problems but that was the only
way I figured I could maintain the center of the bearing on the center of the
tower top.
Clint
----- Original Message -----
From: R Atkins
To: towertalk@contesting.com
Sent: Friday, July 13, 2007 8:02 AM
Subject: [TowerTalk] Yaesu GS-065 Thrust Bearing 25G installation help
needed
Has anybody sucessfully attached one of these to a Rohn 25G flat top
section? The mounting holes are on a small enough diameter that two of them are
partially in the hole through the top plate.
I guess some quick fabrication is on order here, but hearing how others
have done it is helpful.
Please reply direct as well as to the list.
Thanks!
Rusty
K0FE
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