[TowerTalk] FW: Replacement worm gear box for TX-472 motorized tower...

[Grant Saviers]

One additional comment re bearings, in reconditioning an LM354 TriEx I 
found the bad bearings were Boeing surplus aircraft control cable 
sheaves.  Marked with "Boeing + part numbers" and with a pressed in ball 
bearing uniquely made for them.  Apparently TriEx bought a big lot of 
Boeing surplus.  Not to be found in any bearing catalog, but there they 
were on ebay!

So unless you are lucky on ebay or can machine new sheaves or machine 
them to fit stock bearings, the clean and grease fix is an probably the 
best alternative and should last a few years.  While not as low friction 
as ball bearings an oilite sleeve bearing could be machined to fit and 
won't rust or seize up.

Grant KZ1W

On 5/12/2017 21:49 PM, Matt wrote:
> Just wanted to echo Rick's comment.   I have 4 older crank-ups (2 Triex and
> 2 UST) and all have had pulley bearings go dry over the years.  The only
> failures I have seen develop with gear boxes have been leaking seals.  One
> of my towers was, however, acquired with a gear box that was dead on arrival
> and had to be rebuilt.   Other than that, I have found the gear boxes to be
> pretty reliable provided that they are not allowed to run out of gear lube.
>
> Regarding the pulley bearings, replacement bearings are generally very hard
> to find, and replacement pulley assemblies are expensive.   I have had very
> good success reconditioning old tower pulley bearings by drilling a small
> hole in the side shield of the bearing and inserting a hypodermic grease
> needle (available at your local auto parts house) to flush out the old
> grease with new grease.   If the bearing won't turn at all, try running it
> under a parts washer while working the races back & forth to loosen up the
> stiff grease.   Then flush out the old grease with new as described above.
>
> If you do need replacement bearings, I suggest trying a bearing supply
> house.  There is usually one in most larger cities.  It will be best to
> remove the bearing from the pulley and take it to the parts counter unless
> you have a set of micrometers or a good dial caliper to measure the old
> bearing dimensions accurately.
>
> Most pulley bearings simply drive out of the housing (they are press fit &
> peened in place) - look for a snap ring first & if you don't see one then
> it's a good bet it's press fit.   Beware that many pulley bearings can only
> be removed from one side of the pulley.   If you drive it in the wrong
> direction you can shatter the retaining lip on the pulley bore which will
> trash the pulley.   After reinstalling the replacement bearing, be sure to
> peen the pulley from the installation side around the circumference of the
> outside race to help securely retain the bearing in the pulley.
>
> Hope this info is useful & good luck.
>
> 73
> Matt
> KM5VI
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Rick
> Stealey
> Sent: Friday, May 12, 2017 5:20 PM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Replacement worm gear box for TX-472 motorized
> tower...
>
> Do you know the problem is not the pulleys?
>
> I have the same tower.  7 pulleys were bad.  Motor stalled.
>
>
> Rick  K2XT
>
>
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