I would be interested in 'opinions' on the need or utility for only one thrust bearing at the top of a tower vs. two thrust bearings one at the top and the other several feet below the first. Tod, K0
Good Idea> I am planning to install an XM-240 ten feet above a Force 12 C-31XR on a 20 foot 0.25" wall 1026 DOM mast. Sixteen feet of the mast will be above the top of the tower. Tod, K0TO _____ A lo
Two bearings would keep any lateral thrust off the rotor. Mike, NF4L _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@c
Tower top plates and rotator plates are not manufactured very precisely and trying to line up two bearings plus your rotator bearing could be difficult. If it's not lined up exactly it will cause som
I use two because I have a 20 foot mast over the tower with 3 antennas and it gives me a better feeling that the mast won't twist out of vertical when I pull the rotator to lower the mast to get to t
Author: "Kenneth R. Goodwin, Jr." <krgoodwin@comcast.net>
Date: Wed, 12 Aug 2009 10:06:53 -0500
A second thrust bearing normally allows a safe means to remove the rotator (lift the mast and secure using the two thrust bearings). That alone is more than enough justification for two thrust bearin
Given that we have established, per Rohn, Create and others, that the function of thrust bearings is to bear lateral as opposed to vertical loads, can someone please explain to me what benefit, in no
thrust bearing at the top of a tower vs. two thrust bearings one at the top and the other several feet below the first. The alleged purpose of the middle thrust bearing is to hold the mast vertically
Chris, I think you will find that Rohn was only referring to "their" thrust bearing, the TB-3 family. There are other bearings and bushings used, and often required, in antenna installations that che
Hi John: Yes, proper alignment can be a challenge. The rotator plate is welded into my tower at 4 feet down from the top. The objective of the second bearing seemed to me to be to prevent lateral mot
If it's any help, my Create RC5B-3 is specified at 1000Kg horizontal load, by which I assume they mean 9800N. The 'vertical load' is given a 700Kg. Chris _____________________________________________
Author: "John E. Cleeve" <g3jvc@jcleeve.idps.co.uk>
Date: Wed, 12 Aug 2009 19:10:51 +0100
To resolve a similar problem with the head unit of my 60ft lattice tower, I used a heavy duty roller thrust bearing, obtained from a scrapped heavy truck in a vehicle scrap yard, at the top of the he
There are pros and cons where two thrust bearings are involved even when one of them is the rotator. This is a case where there are a lot of "it all depends". I've done it with the rotator near the t
I use two thrust bearings. It's easy to plumb the mast by using the "play" (lack of tolerance) in the piece parts. I use two for the following reasons: 1) Some of my masts are long - in one instance
I agree with Larry and many of the others. I have a 24' mast and use two. I have used two for about 15 years now. I sleep better using two and the rotor maintenance is now a breeze (and non existent!
So what do you do to keep the antenna from spinning out control while the rotator is removed? John KK9A I agree with Larry and many of the others. I have a 24' mast and use two. I have used two for a
I concur, plus the u-bolt keeps the antenna from spinning while the rotator is removed! John KK9A The alleged purpose of the middle thrust bearing is to hold the mast vertically to aid in rotator rep
I have never heard of a rotator mounted inside a tower with only one bearing breaking due to lateral force. Has anyone ever seen this? John KK9A Hi John: Yes, proper alignment can be a challenge. The
I agree with Steve's statement on binding. I have a middle thrust bearing and leave it loose during normal operation (i.e., the screws don't touch the mast.) I'm sure if I tightened the screws the ma
And if it binds just enough, you might not notice in the sense that the rotor will still turn, but you'll end up putting nasty lateral loads on everything simply by virtue of shaft misalignment. I w