On 6/2/2014 1:12 PM, David Robbins wrote:
I have a tb-3 that has been in the air for almost 30 years now, has outlived
several rotors, a bunch of antennas, and a set of guy wires... and I haven't
looked at it since I put it up there... it just keeps on turning. I have
several others on different towers that have been up there 15 to 20 years that
have never been touched either. just how old are these tb-3's that are
requiring all this work??? have they been used in a salt spray environment?
Welll...I'm in central Michigan. About 25 miles from Saginaw Bay (fresh
water) and many hundreds of miles from salt water, unless you count our
winter roads. <:-)) I went through a TB-3 and a TB-4 in less than 6
years. The races wore to the point that the top sat on the bottom and
the edges of the races were like razor blades
Admittedly, I overloaded them, but wanted to see if they'd stand up. I
don't have the name handy, but there are bearings available that
twist-lock to the mast and come in 2 and 4 bolt mounts. I'm sure some
of the group have the names and numbers.
They do need a slight mod to keep water from collecting on the bearing.
They are smoother, stronger, and a fraction of the cost of TB series of
bearings. They do require a yearly greasing (probably more often when
located near the coast.)
Jun 2, 2014 01:03:10 PM, charlie@thegallos.com wrote:
Exactly what I'd do if I needed to rebuild a thrust bearing, unless I could get
some free torlon or vespel (haha, I'm funny, those are crazy expensive and
overkill)
Low rotation rate, shock loaded, out in the weather, where they wi
Tip over towers that slightly invert the mast when down, only need a
collar or collars to prevent the mast from sliding out with "Plastic
bearings". A plastic washer between the collars might help.
73
Roger (K8RI)
ll receive little in the way of maintenance is the place where engineering plastics like
nylatron gsm shine. Heck, I can't see why any tower thrust bearing mfg would do anything
else except to market to folks who say "ball bearings have to be better than
PLASTIC"
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