Plastic thrust bearings are the way to go. Black UHMW is another great
(and cheaper) material. Both UHMW or Nylon are UV susceptible but if
black or GSM they should last a long time. I recently disassembled
white UHMW bearings for a 3" mast that were just showing crazing (but no
wear) after 7 years in service at a contest station. This design, which
I will replicate 5 times on a new tower has a 5" diameter 6061 1/4"
thick disc held by a collar set screwed to the mast on top of 2" thick
black UHMW, so this bearing holds the weight (thrust) as well as radial
alignment for the top end of 4 side mounted 3" masts and one top of
tower bearing above an internal rotator.
Grant KZ1W
On 6/2/2014 9:41 AM, George Dubovsky wrote:
I think I've mentioned it before on this forum, but I converted my TB-3
thrust bearings over to thrust bushings by machining them to accept inserts
made from a dry lubricant-loaded composite, Nylatron GSM. No grit-trapping
grease, no fretting of the race and no routine maintenance required. One
has been in service since 2005 and one since 2010. From the outside they
look identical to the stock TB-3. The only negative is that you can not use
them on a foldover tower where the mast gets inverted occasionally, since
there is no race of balls to resist "up" force.
Chunks of nylatron (or equivalent) turn up on ebay routinely, but you do
need access to a small lathe to do the modification.
73,
geo - n4ua
On Mon, Jun 2, 2014 at 12:14 PM, Grant Saviers <grants2@pacbell.net> wrote:
McMaster has balls in stainless, 304, 316, and 440. 316 isn't the hardest
but is the most corrosion resistant. They are what I use for rotator
rebuilds.
If you meant "cratered" which happens when the mast oscillates then it
might be possible to smooth that out a bit with sandpaper since the bearing
is pretty crude to start with. Works for rotator races. Adding a couple
of grease fittings which get a shot of grease every year will also help a
lot. I like the TFE loaded full synthetic "Super Lube" formerly by Synco,
now owned by Loctite.
Grant KZ1W
On 6/2/2014 7:20 AM, Charles Gallo wrote:
Ceramic balls have an issue, they really really don't like jarring loads.
Their failure mode is to break, vs rust
--
73 de KG2V
Charlie
On Jun 2, 2014, at 10:00 AM, Mike Reublin NF4L <nf4l@comcast.net> wrote:
Does anybody know what size balls are in the Yaesu GS-065 thrust
bearing? My cheap caliper isn't precise enough. Looks like 3/8". They're
rusted and bumpy.
Has anyone had experience with ceramic balls?
The grease is so hard I'm having to soak it off so I can see the races.
If they're crafted, I'll just replace the whole thing.
73, Mike NF4L
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