What typically happens to bronze sleeve bearings is
two things:
1) the oil that impregnates the bronze foam runs short,
and no longer wicks up to the shaft/bronze interface
2) the bronze without oil is abrasive, and wears away
the steel shaft until it is small enough that it cannot
be fully supported on a film of oil. This allows the
shaft to rattle around in the bronze hole, making noise
and doing more damage.
When you oil up such a mess, the oil will not soak into the
bronze "sponge", because the friction smears the bronze until
all of the pores in its hole are closed. The oil in the
now too large gap just gets slung away until it is once
again dry and making noise.
A new bronze/oilite bearing can be substituted, but you will
probably find that one that is undersized enough to fit in
the worn section of the shaft, will be too tight to fit
over the un worn shaft. The solution is to reduce the shaft
size just enough to fit through the new bearing...
-Chuck Harris
On Sun, 7 Apr 2024 13:59:11 -0400 (EDT) "n4buq" <n4buq@...>
wrote:
That sounds like some slick stuff. :)
At this point, I'm reasonably sure the problem is not lubrication but
just an inherent property of the fan.
Thanks,
Barry - N4BUQ
Greetings,
There may yet be a solution. There is a product called ¡°Energy
Release¡± Anti-friction Metal Conditioner. It is available at many
different places including Amazon.
More than twenty years ago I was introduced to this product by a
friend who became an ¡°Energy Release" independent dealer. I think
back then the company was perhaps just starting and they were
making their name through independent dealers who would go around
and demo the product.
I have used it as necessary on a wide variety of situations since
my friend showed the stuff to me. It doesn¡¯t take very much to
make a significant difference. The 8 fl. oz. Bottle listed on
Amazon should last a lifetime, probably more. I¡¯m still using from
the bottle I bought more than twenty years ago and it still works
just fine.
My friend had a demo machine where he would install a steel space
on a 1/4 HP motor arbor. He had a long handle that had a fixed
pivot point and he would bring it in contact with that space and
easily bring the motor to a dead stop. Then he would apply just a
little of the Energy Release to that steel spacer and try as hard
as he might he could not generate enough friction force to stop the
motor.
I was impressed and I have never been disappointed using it.
This might be worth a shot. If it doesn¡¯t resolve this situation I
am certain you will find many uses for it over the coming years.
Best wishers!
Ken
On Apr 6, 2024, at 10:43 PM, n4buq <n4buq@...> wrote:
I finally got around to removing the fan motor. I was able to get
it apart and, unfortunately(?) it uses a bronze (oilite?) bushing.
There appeared to be sufficient oil on the shaft but I went ahead
and cleaned everything and applied some synthetic oil to be shaft,
bushing, and soaked the oil sponges with it. With the condition it
was in, I didn't expect much, if any improvement, and I wasn't
disappointed. I guess I'll just put up with the noise.
Thanks,
Barry - N4BUQ
Thanks, Chuck. The manual gives a procedure for lubricating the
motor but, so far, I cannot find the places where it states to
apply the oil. Apparently there should be holes to do that but I
don't see them. I think I will go ahead and remove the fan (it
needs a bit of cleaning anyway) and see if I can disassemble,
clean, lube, and reassemble it. Hopefully that will help/cure
most of the whine.
Thanks again,
Barry - N4BUQ
The whine is the ball bearings rolling on a not so smooth
race. The problem could be the metal of the race has been
brinelled by the balls smacking on it... kind of like little
ball peen hammers. Or it could be chunks of dried grease
making noise as they get into stuff.
Most people that try to lubricate these fans don't realize
that there are two ball bearings in the motor, one you can
easily see if you remove the label, and the other spring
loaded to the other side of the fan. You have to lube them
both.
The motors come apart pretty easy. Usually, there is a "C"
ring, or a plastic washer like piece that is clipped over
a groove in the bearing shaft. Remove it, and the fan, and
both bearings will pop right out.
Then remove one seal from each bearing, and wash them out with
naptha, or varsol, or gasoline... It only takes a little, and
blow them try. Don't let them spin very fast, as it will
Brinel the bearing races.
Put a little dab of lubriplate in the bearing, and you are good
to go. Don't pack them full, that only turns the bearing into
a grease pump, and makes everything turn slow, and get hot.
Assembly is the reverse of disassembly.
-Chuck Harris
On Tue, 2 Apr 2024 15:42:51 -0400 (EDT) "n4buq"
<n4buq@...> wrote:
Do all the 140-series scopes have extremely noisy fans? My
140B is excessively noisy and I'm wondering if a different fan
could be substituted. I don't mind the wind noise all that
much, the whine that's associated with it is pretty obnoxious.
I haven't lubricated it yet but I suspect that won't really
knock down that whine very much (if at all). Looking for
suggestions.
Thanks,
Barry - N4BUQ
