LX200 Gear Cleaning & Re-Greasing
Subject: Gear Grease Recommendation --part
1 of 4 
From: Michael McNeil <cno caltel.com> Date: March, 2000
A friend that worked at Celestron once, and now, or use to at Meade
told me once, on the Compustar, not much difference as far as RA gear
& worm go, said take a tooth brush dipped in denatured alcohol,
and run the scope around completely with the old tooth brush, to clean
all junk off, then, using , "sta-Lube, white grease", common
to farm equipment and industrial, add some of this lithium base grease
to the tooth brush on thick. Then while it is held to the worm run the
scope around the RA, and keep adding the grease, until there is a smooth
spread of it around the main gear. This stuff is moisture resistant,
prevents rust, and stops binding. its worked great for the Compustar.
All else, I stay with the high vacuum grease, but not on the dec or
ra gears. The product # is 37706 from "Stay-Lube" Inc.
PS Stay away from the graphite grease, Meade love this stuff, after
awhile it spreads out, but leave the graphite its self in clumps, that
can cause a jam!
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Subject: Gear Grease Recommendation --part 2
From: Doc G, Date: March, 2000
> Any suggestions as to what type of grease to use on the RA gear?
I've noticed
> an increase in noise while slewing (if that's possible) but it
is only on
> about a 60 deg portion. I looked at the gear and it appears it
is completely
> void of grease. Thanks in advance.
I have seen a lot of recommendations of "Moly" grease. A
good one is Dow Corning BR2-Plus. But be warned that you want to put
the grease on the gears not on your hands. The Moly penetrates the skin
and dissolves your liver. This grease is a black color and stains everything
it touches. It looks like the grease that is on the gears in the LX
scopes.
I prefer to use a low temperature grease or one that tends to stay
in place. There are several good ones. LubriMatic works on gears well
and will stay in place. It also has a nice blue color.
Another, and the one I like the best, is Dow Corning "33."
It has silicone in it and has a nice pink color. It has very good temperature
characteristics. So you have a choice. Black, blue or pink. Actually
for this low pressure slow speed application it matters not one whit
what you use.
On precision microscope slides and gears, vaseline and lanolin are
often used. That is totally safe to smear on your hands as well. Does
away with wrinkles I am told. There is also a nice grease with Lithium
in it. I is white and stays in place. I don't have any right now but
have used it and found it fine. Another grease that tends to stay in
place is pump grease. It is very waterproof in case you have severe
dewing problems. This grease is "grease" colored.
The LXs have the black stuff and the pink stuff in them. But I think
their black stuff is not Moly but carbon. Do not use carbon grease.
It clusters and gets sticky. I would use the pink stuff rather than
the black stuff. The blue stuff which is really cheap and quite attractive.
A small tub of it (16 oz) will last you a lifetime unless you do a lot
of automobile bearings and the like.
Seriously, you should use some kind of grease. I do not believe that
for this application it matters much what you use. I would select a
grease that tends to stay in place. The tube or tub it comes in will
usually state that feature.
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Subject: Grease Recommendation --part 3
From: Bill Wood <wrwoodqwest.net> Date: Oct 2001
I used black moly grease called Action Lube Plus from Brownell's, a
gunsmith supply house. Some of the finest specialty lubricants are made
for firearms. The most intense application for grease in firearms is
on the slide mechanism of semi-auto target pistols which sometimes fire
a 1000 rounds a week in practice and matches. This is what the moly
grease is for. But it is also fine for telescopes because it is virtually
the same consistency as the Meade grease and it handles extreme temperature
ranges. A small can will last for years and costs only a few bucks.
Check: <http://www.brownells.com/>
However I do not believe the type of grease is all that important as
long as you use name brand quality grease and match the viscosity of
the Meade grease and make sure it's temperature range will be OK for
your climate. If the grease turns to stone in cold weather you are in
trouble if your winters are cold. Remember the speeds that these telescope
drive mechanisms run at is very very slow and the lubrication demands
are not high. The gap filling properties between parts and viscosity
are what counts more than heavy duty lubrication. Doc G recommends a
grease that he likes and that is probably as good or better than the
stuff I used. I used the gun grease because I had it handy since I am
a target shooter not because I think it is better than the grease Doc
G suggested.
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Subject: RA Drive Grease Recommendation -- part 4 of 4
From: Bill VanOrden <beevo@cox.net> Date: Nov 2003
I have been using this stuff for a myriad of uses: <http://www.philwood.com/webcatolog/page18.htm>
Subject: Gear Cleaning Procedures --part 1 of 7
From: Gene Chimahusky <lynol1000yahoo.com> Date: Oct 2002
Check Doc G's site for his breakdown: <http://www.MAPUG-Astronomy.net/ragreiner/RABase.html>
When you open the top cover between the forks it is amazing to see
the small Allen head screw that holds it all together!
I did not dismount my OTA or forks so I found I could separate the
top from the bottom by having someone hold the bottom base and then
just lifting with a little force on the top versus tapping them to dislodge
the lower bearing. Getting it back together with a 12 I would advise
two people because getting the cup on the upper over the outer race
on the lower large bearing takes a little fine positioning if you do
not take the forks and OTA off.
As far as actual cleaning I used rags to remove all the excess, then
many toothpicks in thru the teeth while washing down multiple times
with -hot- 'Dawn' dishwashing liquid (cuts grease quite well). When
no residue was left anyplace and everything was nice and shiny I started
the re-assembly. I first vacuumed and wiped the internal of the base
down multiple times trying to get everything out.
I used some lithium based wheel bearing grease that I have been using
on the DEC axis and found it to be plenty viscious at cold temps and
not runny at 'high' temps. Others will have more precise
recommendations I am sure.
I did take the little ball bearing out of the hinge and oil'ed the
cup it fits into. There are two ball bearings, one at the other end
with an Allen head adjuster but to get that one out would require removing
the gear box, just call me 'chicken'! But I did oil that cup up also
when I had the outer ball out and had clearance to get the oil in.
All in all about three hours including finding my Dremel to slot the
cover plate Allen head.
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Subject: Gear Cleaning Procedures -- part 2
From: Gene Chimahusky <lynol1000yahoo.com> Date: Nov 2002
It has been over a month since I performed the gear cleaning on my LX200 classic and I feel I can now report it was successful
at removing the 'jumps' I was seeing. <http://www.geocities.com/lynol1000/lx200_internals/>
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Subject: Gear Cleaning Procedures -- part 3
From: Randy Marsden <jmarsdensan.rr.com>
Gene, Congratulations! I followed your example and tore down the lower
end of my LX200. I cleaned all of the gears, including those inside
the motor gearbox. I carefully centered the big wheel and removed all
of the heavy grease, except that for moving the RA setting circle, and
lubricated the wheel with low-temp grease and all other bearing surfaces
with Mobil One synthetic oil, which has good low temperature properties.
I cleaned the gears inside the motor gearbox with a fine scribe, and
lubricated the gears and shafts with Mobil One, removing all excess
oil with lint free, non-woven lab wipes. My scope is much quieter and
my preliminary measurements indicate that the PE is reduced by a factor
of three, from 30 arc-seconds peak-to-peak, to no more than 10 arc-seconds
peak-to-peak. A thirty second component of the PE is now so small that
I cannot detect it in the first data that I have analyzed.
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Subject: Gear Cleaning Procedures -- part 4
From: Doc G
I am very happy to hear that the cleaning has helped several of you.
It is a very important operation to getting excellent RA action. To
put the cleaning in perspective, remember that a particle of a few microns
size with cause an angular wobble of a few arc seconds.
The gears have to be in a real sense microscopically clean.
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Subject: Gear Cleaning Procedures -- part 5
From: Randy Marsden <jmarsdensan.rr.com>
----- Original Message -----
From: Gene Chimahusky
> You were brave enough to go inside the gear box? Was
> it tricky to get the encoder mask back into position
> (with or w/o the help of a dual channel oscilloscope, of
> which I do not have :( )? I am not plagued by bad PE
> and with training I can get it ok, but I have two
> points in the 200 count down (57 and 47) that I have
> to over train before the and after the count to make
> up for the moves that occurs every cycle. I sure would
> like to make that go away.
> http://www.geocities.com/lynol1000/pec/index.html
> Ssee count 22 and 24 of the second graph after a
> mediocre training cycle.
Gene, I did not need to unscrew the cover of the gear box. On my scope,
the top of the box is covered with a thick tape. I carefully peeled
this back to get to the inside. Then, I would turn the top of the gear
closest to the motor to clean all of the teeth, particularly deep into
the grooves where some grit had accumulated. On one of the plastic gears,
the was some small particle imbedded in the gear. I used a very fine
scribe to pop these out and then a small riffling file to smooth the
gear surface. The was quite a bit of dried grease in the teeth of all
of the gears. I though about using solvent but was concerned about leaving
a residue on the photo sensors. So I cleaned each tooth of each gear
individually with a toothpick dipped in lacquer thinner. After everything
was clean, then I added a tiny drop of Mobil One oil to each gear and
to their shafts. Then I connect the motor to a D-Cell battery and let
the motor run for a couple of minutes to distribute the oil. I followed
this by removing the excess oil with a non-woven lab wipe. The gear
box sounded much smoother, draws less current when slewing the scope
and seems to have less PE. When (if) the skies clear, I will obtain
some more data on PE, and PEC training results.
I also did the same gear cleaning routine on the declination drive
and it also runs much more smoothly. On both drives, I also adjusted
the ball bearing pivot to make it smoother and let the worm engage more
smoothly.
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Subject: Gear Cleaning Procedures -- part 6
From: Mike Dodd <mikemdodd.com>
>...where do you get riffling files? or riffler
One place is Micro-Mark <http://www.micromark.com>.
Their catalog lists several types of riffler files; you probably want
the "fine cut" set, no. 33111A (10 files) for $19.95.
Also try searching on "riffler file" which brought up 751
hits for me.
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Subject: Gear Cleaning Procedures -- part 7
From: Roger Hamlett <ttelmahntlworld.com>
>...where do you get riffling files? or riffler
A good engineering tool supplier should do them. A web search on the
European web sites, found several engineering companies listing them.
Have a look at: <http://www.hesondiamant.de/Seitenenglisch/index-englisch.htm>
To see what they look like, see sets 4 and 5.
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Subject: Gear Cleaning Procedures -- part 8 of 8
From: John Mahony, Date: March 2005
>Having a repeatable bump/jump each and every 30 seconds (or so) probably
> means some work. This probably indicates something caught in one of the
> teeth of the first gear of the drive reduction unit.
Yes, it rotates once every 30 seconds.
>For notes on the drive train see Doc G's page: <www.mailbag.com/users/ragreiner/PECOper.html>
There is a strip of rubber tape covering one side of the gearbox, so it's easy to get in there and clean crud out of the teeth. Just be careful of the encoder wheel- don't get any grease in the gaps, and don't knock the mask loose. Also, be careful
of the stiff wires going to the LEDs and optical sensors. Since they're stiff, they break easily, and they typically break
right at the base of the LED/sensor, so they're a real pain to fix -- nothing left to solder to.
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