Meade LX90: problem bolting telescope assembly to tripod.

I recently acquired a second hand (but hardly used) Meade LX90 and I
am having trouble attaching the telescope assembly to the field
tripod.

The threaded central hole in the bottom of the drive base is appox. 1
3/4" deep but the threaded rod will only screw into it about 5/8". The
result is that the telescope is loosely sitting on top of the tripod
head rather than snugly secured to it. Have any LX90 owners
encountered this problem? Any suggestions?

Jay Loughlin
Tucson, AZ

Hi Jay, Sounds like either the threads on the threaded Rod, or more
likely, the threaded hole in the drive base was not tapped/threaded
cleanly.

Or, Perhaps the original owner when using this scope was not too careful
about how he tightened the Scope to the Tripod, and over-tightened the
Rod to death, and in effect, perhaps distorted/damaged the threads on
the drive base?

In either case, you'll most likely need the correct size tap for chasing
the threads on the Drive Base. (Or a Die for chasing the Rod if it
somehow appears damaged also?)

I believe this is 3/8"x16 but please don't quote me on this. Ideally, a
Tap called a Bottom Tap would be the best thing to use for the drive
base, but I would imagine a standard Tap will work well also. Just
don't try running it too far through the bottom of the Drive Base. Do a
1/2 inch, then back out, then thread in again, cleaning/chasing the hole
slowly

You might be able to find this one singular tap at a hardware store
(True Value/Home Depot) or a good large Auto Parts Store.

Perhaps call around in the phone book for availability, so you don't
waste mucho gas trying to find one. Should only cost about $5-8.

Also, a local machine shop will do this for you, and should also only
charge you just a few bucks. This might be the best way to go. They'll
know immediately what the problem is.

After cleaning/chasing the threads, Makes sure there are no remaining
shavings of metal in the base. Blow out with canned air if you have it.

I then recommend placing either a small dab of grease, or anti-seize on
the threads of both parts where they join to prevent further
wear/galling to the parts. Hope this helps. Mark

Jay Loughlin wrote:
I recently acquired a second hand (but hardly used) Meade LX90 and I
am having trouble attaching the telescope assembly to the field
tripod.

The threaded central hole in the bottom of the drive base is appox. 1
3/4" deep but the threaded rod will only screw into it about 5/8".
The result is that the telescope is loosely sitting on top of the
tripod head rather than snugly secured to it. Have any LX90 owners
encountered this problem? Any suggestions?

Jay Loughlin Tucson, AZ

Hi Jay,

There is a certain knack to getting the threaded rod in. If everything's
lined up correctly, it should go in with very little force. It's really
worth taking the time to get it right - if it's hard to screw in, you're
probably not properly aligned.

First, you need to make sure the head is level and that all the legs are
evenly spread. The hinges often have quite a bit of sideways play in
them, so you may need to wiggle them a bit to get the feet into a nice
equalateral triangle. Alternatively, you can try picking the whole lot
up by the top of the threaded rod and giving it a good shake, which will
usually get things in the right position. This is however not such a
pleasant experience, so you may want to support it by holding the knob
at the bottom.

When you're in the right position, the spreader bar should be level and
contact all three legs when pushed up against them. If you've got this
far, screwing the rod into the base should be a piece of cake.

OTOH, it's very easy to cross the threads and too many folk have the
tendancy to force it, which can cause damage. If this is the case, the
thread in the base is pretty soft, so you should be able to get it back
into a reasonable shape by removing the rod from the tripod and screwing
it in straight a couple of times.

Best of luck,

Steve

--
Steve Maddison
Den Haag, The Netherlands
http://www.cosam.org/

On 30 Oct 2004 18:47:28 -0700, Jay Loughlin wrote:

I recently acquired a second hand (but hardly used) Meade LX90 and I
am having trouble attaching the telescope assembly to the field
tripod.

The threaded central hole in the bottom of the drive base is appox. 1
3/4" deep but the threaded rod will only screw into it about 5/8". The
result is that the telescope is loosely sitting on top of the tripod
head rather than snugly secured to it. Have any LX90 owners
encountered this problem? Any suggestions?

I had that problem when I first got mine (brand new).

In my case, the tripod adapter was simply threaded poorly. In your case,
the threads may have been damaged, or the tripod bolt may have bad
threads.

In the first two cases, one option is to rethread the adapter. If the
bolt is bad, you'll want to replace it.

The adapter is held in by three small hex-head screws on the base. You'll
know which ones as soon as you look a the bottom.

Take the adapter out, and remove the tripod bolt from the tripod (it will
requite removing a small clip, which you shouldn't lose). Put some kind
of lubrication on the bolt (white lithium grease would probably be best,
but I used what I had on hand, which was WD40), and screw it into the
adapter *backwards*. That is, start from the part of the adapter that's
internal to the scope.

As long as you're sure you started it straight, force it all the way
through. It should now screw in easily in either direction.


--
- Mike

Remove 'spambegone.net' and reverse to send e-mail.

Or, Perhaps the original owner when using this scope was not too careful
about how he tightened the Scope to the Tripod, and over-tightened the
Rod to death, and in effect, perhaps distorted/damaged the threads on
the drive base?

Mark,

Knowing the previous owner, I suspect you're right. Getting the
threads cleaned up shouldn't be too much of a problem. I think we have
the equipment where I work.

Jay

There is a certain knack to getting the threaded rod in. If everything's
lined up correctly, it should go in with very little force. It's really
worth taking the time to get it right - if it's hard to screw in, you're
probably not properly aligned.

First, you need to make sure the head is level and that all the legs are
evenly spread. The hinges often have quite a bit of sideways play in
them, so you may need to wiggle them a bit to get the feet into a nice
equalateral triangle. Alternatively, you can try picking the whole lot
up by the top of the threaded rod and giving it a good shake, which will
usually get things in the right position. This is however not such a
pleasant experience, so you may want to support it by holding the knob
at the bottom.

When you're in the right position, the spreader bar should be level and
contact all three legs when pushed up against them. If you've got this
far, screwing the rod into the base should be a piece of cake.

OTOH, it's very easy to cross the threads and too many folk have the
tendancy to force it, which can cause damage. If this is the case, the
thread in the base is pretty soft, so you should be able to get it back
into a reasonable shape by removing the rod from the tripod and screwing
it in straight a couple of times.

Best of luck,

Steve


Steve,

Before taking more drastic steps I'll try you're suggestions. Got a
feeling damage has been done though.

Jay

I had that problem when I first got mine (brand new).

In my case, the tripod adapter was simply threaded poorly. In your case,
the threads may have been damaged, or the tripod bolt may have bad
threads.

In the first two cases, one option is to rethread the adapter. If the
bolt is bad, you'll want to replace it.

The adapter is held in by three small hex-head screws on the base. You'll
know which ones as soon as you look a the bottom.

Take the adapter out, and remove the tripod bolt from the tripod (it will
requite removing a small clip, which you shouldn't lose). Put some kind
of lubrication on the bolt (white lithium grease would probably be best,
but I used what I had on hand, which was WD40), and screw it into the
adapter *backwards*. That is, start from the part of the adapter that's
internal to the scope.

As long as you're sure you started it straight, force it all the way
through. It should now screw in easily in either direction.

Mike,

I was looking at it and thought about doing just what you suggest. Of
course if worst comes to worst I suppose I could get both the adapter
and bolt replaced.

Jay

On 31 Oct 2004 09:28:34 -0800, (Jay Loughlin)
wrote:

There is a certain knack to getting the threaded rod in. If everything's
lined up correctly, it should go in with very little force. It's really
worth taking the time to get it right - if it's hard to screw in, you're
probably not properly aligned.

First, you need to make sure the head is level and that all the legs are
evenly spread. The hinges often have quite a bit of sideways play in
them, so you may need to wiggle them a bit to get the feet into a nice
equalateral triangle. Alternatively, you can try picking the whole lot
up by the top of the threaded rod and giving it a good shake, which will
usually get things in the right position. This is however not such a
pleasant experience, so you may want to support it by holding the knob
at the bottom.

When you're in the right position, the spreader bar should be level and
contact all three legs when pushed up against them. If you've got this
far, screwing the rod into the base should be a piece of cake.

OTOH, it's very easy to cross the threads and too many folk have the
tendancy to force it, which can cause damage. If this is the case, the
thread in the base is pretty soft, so you should be able to get it back
into a reasonable shape by removing the rod from the tripod and screwing
it in straight a couple of times.

Best of luck,

Steve


Steve,

Before taking more drastic steps I'll try you're suggestions. Got a
feeling damage has been done though.

Jay

Re-running the bore with a tap is a good idea on any
mass produced product. I took a look at a recent
Meade adapter plate for the LX-90 to adapt it to a regular
wedge (the LX-90 only has the centre hole, not three around
the periphery like the LX-200 so it needs an adapter plate)
and the threading was terrible. You could see the pilot holes
they made were done with a drill bit that was too large, resulting
in threads with about 1/2 the "depth" you'd normally get.
While not dangerous (the scope won't fall off) it was disconcerting.

Hi Jay, Just running the threaded rod through (Which ever way you go)
with whatever force it may take, will certainly not give you the same
good results as using a Tap, or Die (And Tapping oil).

Using this previous technique will possibly make matters worse. I'm
sure you don't wish to get this rod seized in the base, then wind up
resorting to pipe wrenches in frustration to try extracting the Rod.

As another poster has mentioned, the bottom base plate is supposedly
removable from the LX-90 (I didn't realize this, as I never owned a late
model Meade SCT) I'd remove the base plate, and cart both Base plate,
and Threaded Rod down to a local machine shop, leaving the scope at home
where it is safe.

You'll probably be in, and out in 5 minutes, and many of these shops may
not even charge you a red cent. If they do, I'm sure it won't be any
more than $7-10, and you'll have peace of mind knowing that the job was
done right.
Mark D.

Mark D wrote:
Hi Jay, Just running the threaded rod through (Which ever way you go)
with whatever force it may take, will certainly not give you the same
good results as using a Tap, or Die (And Tapping oil).

Using this previous technique will possibly make matters worse. I'm
sure you don't wish to get this rod seized in the base, then wind up
resorting to pipe wrenches in frustration to try extracting the Rod.

As another poster has mentioned, the bottom base plate is supposedly
removable from the LX-90 (I didn't realize this, as I never owned a late
model Meade SCT) I'd remove the base plate, and cart both Base plate,
and Threaded Rod down to a local machine shop, leaving the scope at home
where it is safe.

You'll probably be in, and out in 5 minutes, and many of these shops may
not even charge you a red cent. If they do, I'm sure it won't be any
more than $7-10, and you'll have peace of mind knowing that the job was
done right.
Mark D.


Mark,

You're of course absolutely right - I should've been a little clearer
with my explanation. If there thread's off by any significant amout,
retapping is definitely the way to go.

--Steve