A Restoration

[Alan64]

1 hour ago, johninderby said:

Mitutoyo are a bit like Snap-On tools in a way in that they are what professionals that need tools they can depend on use. 👍🏻

Yes, Snap-On tools are stellar as well, although I've never owned one.

[Alan64]

For the RA-axis, the circles for four washers have been described onto the 0.020" sheet of phosphor-bronze.  Note, there on the right at the bottom, where the compass leg went astray, but no matter as that lies within the scrap area...

Yes, four washers, two for the RA worm-gear, and two for the secondary ball-bearing assembly...

The dimensions of the ball-bearing washers were arrived at via these measurements...

Those parts are actually sloppily-fitting.  As a result, I will be making a shim from two 6mm-wide strips of 0.008"-thick phosphor-bronze...

The inner-diameter of the innermost washer is 1mm larger than the outermost, and per the RA-shaft...

...34mm and 35mm, roughly.  The red line illustrates the division between the inner and outer portions of the shaft.

Once the four washers are cut out, dressed and polished, the RA-axis can be re-assembled.

I used Super Lube grease for the latitude-axis, but I'm wondering if I should use marine grease for the rest of the mount-head.  I haven't decided yet.

[Alan64]

I broke several of my jeweller's blades getting these cut out.

The sawing is done, but I've yet to snip the larger washers out from the sheet.

It turned out that the thickness of the ball-bearing's original enclosures, surrounds, whatever, are also 0.020".

Edited July 18, 2021 by Alan64

[Alan64]

https://www.youtube.com/watch?v=b9xDvX2_v0k

The secondary RA-washer...

 

There it sits, and perched atop its ridiculously narrow ledge all round.  Meh.

Ah, but this, this, the primary RA-washer, and which happens to be the narrowest of the four washers...

Glamour shot...

All of the gear's teeth are visible from overhead, which is why it's narrower than the secondary washer...

You don't want the washer interfering with the worm as it meshes with the gear.

This, yea, this, is what makes the Earth stand still...

Edited July 18, 2021 by Alan64

[Alan64]

I have already made merry mention of galvanic corrosion, and when mixing aluminum with other metals.  Although, that should not be a problem if the metals are thoroughly greased, but never to excess.  You don't want globs of grease within your mount-head, again, like when it left the factory.  Then, the manufacturers do combine brass worms with aluminum gears, so it can't be the monster I've suspected; or can it be?

There is another caution that presents itself.  The plastic washers would perhaps or definitely never wear down and away the aluminum surfaces with which they come into contact.  Plastic would seem to be softer than aluminum, at first thought at least.  But what about bronze, bearing, rubbing, against said surfaces? 

If indeed a problem, I would be wary of using bronze within a go-to equatorial, with its motorised slewing-speeds, over the months and years.  Copper, and brass even, are softer than bronze, and therefore less destructive.  As for myself, my enhanced mount-head will motion ever so slowly, even when simply motorised with a small drive, like the pendulum of a clock, or a tortoise even.

Got a CG-4, or an EQ-3?  Here's what's inside of it: plastic and red fibre washers...

Get those out of there, if you might, and add ball and/or needle-thrust bearings even.

[Alan64]

The birth of the two shims for the inner-diameter of the secondary ball-bearing assembly...

Why, they're twins!

[Alan64]

I love pie...er, π, pi...

35.6mm x 3.14(ad infinitum) = 111.84mm

How about an even 111mm...

They will actually be somewhat shorter when finished, and the ends blunted, rounded.

[Alan64]

I had gone out to one of my local big-box hardware/lumber stores yesterday afternoon, and got a tube of Lucas Marine grease.  I've had the Super Lube for a few years...

...the one white, the other a greenish blue.

Jeff DeTray, aka "Astronomy Boy"...

http://www.astronomyboy.com/

...is something of a pioneer in refurbishing the earliest of these larger, Chinese-cloned, equatorial mounts, the first-generation CG-5 in particular(I believe Helios-branded in Europe).  Mr. DeTray found rough areas within his CG-5 mount-head(s), but I did not within this Meade LX70, not in the slightest.  Mr. DeTray also returned the plastic washers to the mount-head, whereas I will not.  In addition, the gentleman stated that he has had no personal experience with the second-generation CG-5, manual still, but with ball-bearings, and most likely identical to the Meade LX-70.  

Robert Burns, mentioned within DeTray's site, who refurbished his second-generation CG-5(or the third, a CG5-GT, that is, the go-to variant) used Quaker State marine-grease to re-grease his mount-head, however that particular marine-grease has been discontinued, and for quite some time.  But lo and behold, I did find three tubes of the stuff this morning...

https://i.imgur.com/igMKXb0.jpg

No, I won't be getting a tube, but it was the use of such that sparked my interest in marine-greases.

These marine-greases are perhaps primarily for water-craft and such, hence "marine".  Such are large, and containing large-scale parts.  By comparison, these mount-heads contain relatively small parts, for relatively smaller loads, and perhaps in no need of such a heavy-duty grease.

However, I will be using the new marine-grease for this mount-head, and for these two reasons...

I live in a humid, sub-tropical climate.

I'm not thoroughly convinced that Super Lube is head and shoulders above the rest.  

All that's left to finish before reassembling the RA-axis are the shims for the secondary ball-bearing assembly.

[Alan64]

The shims for the secondary ball-bearing assembly are completed...

Both shims within the ball-bearing assembly...

The shims are not only to take up any slop, but just as importantly, perhaps even more so, to isolate the steel inner rim of the assembly from the threaded aluminum of the RA-shaft.  I may not be able to insert both shims in the end, but we'll see, as one will do just as good a job as two.

Bronze is truly beautiful, when it's not tarnished...

Edited July 20, 2021 by Alan64

[SpookyKatt]

I would have thought that with all your clever re-engineering of the mount and hopefully improvement
a thick grease would be unnecessary and you could of gotten away with something like superlube ?

I mean I don't really know much about this kind of stuff but would you not be concerned that a thicker grease 
might me more of a hinderance now ?

Kathleen

[Alan64]

Just now, I took a small dab of the Lucas marine-grease, and rubbed it between my thumb and forefinger.  I then did the same with the Super Lube.  I did both twice.

As a result of this "taste" test, I will be greasing this mount-head with Super Lube, rather.  I can use the other for more common tasks, and unrelated to astronomy.  Why, Super Lube is waterproof itself.

[Alan64]

11 minutes ago, SpookyKatt said:

I would have thought that with all your clever re-engineering of the mount and hopefully improvement
a thick grease would be unnecessary and you could of gotten away with something like superlube ?

I mean I don't really know much about this kind of stuff but would you not be concerned that a thicker grease 
might me more of a hinderance now ?

Kathleen

Excellent questions, those, and as it turned out, prior to reading your post, I had already decided to forego the marine-grease.  Super Lube is definitely super, superior.

[wookie1965]

I wish I was up to this standard of engineering truly a joy to read and see the pictures. 

If you was of a mind and I had the money I'd love to send my EQ5 goto to you and let that engineering brain of yours on it, that I think would increase accuracy enormously. I would be hitting every target once balanced and polar aligned. 

[Alan64]

10 hours ago, wookie1965 said:

I wish I was up to this standard of engineering truly a joy to read and see the pictures. 

If you was of a mind and I had the money I'd love to send my EQ5 goto to you and let that engineering brain of yours on it, that I think would increase accuracy enormously. I would be hitting every target once balanced and polar aligned. 

You flatter me, sir.  But I think that you can do this yourself.  That's why I'm detailing everything.

[Alan64]

The time had come, and upon awakening from my slumber...

All surfaces that touch one another were, shall I say, conservatively slathered with the Super Lube grease.  This also includes the full outside length of the RA-shaft, and the outside of the RA worm-gear.  Now, if the latter proves a problem, when clamping the axis, I can remove the grease.

   

 

[Alan64]

The slathering continued...

 

Only one shim would fit, and that will do.

 

You want to screw the RA lock-nut onto the shaft until you come to a dead-stop.  Then, back the nut off one-quarter of a turn, and tighten the nut's three set-screws.

*NOTE: Be certain not to mistake the dead-stop caused by the initial, factory set-screw indentations into the aluminum threads, and for the actual dead-stop either a tad farther, or a tad behind, whichever.

O! My stars!  The motion is though it were temporarily greased with the smoothest butter imaginable, and with no slop whatsoever.  I could not be more pleased.

There it is, peeking through those holes: the secondary RA-washer, and perched atop that narrowest of ledges!  Synta!

[Alan64]

It may be worth noting, also, that the bronze washers I made for the secondary ball-bearing assembly had to fit, drop into, this depression...

I arrived at two 0.008"-thick shims for the secondary ball-bearing assembly by subtracting the widest diameter of the RA-shaft(34.76mm) from the inner-diameter of the ball-bearing assembly(35.6mm) = 0.84mm.  I then divided that by four, and for .21mm(0.0082677165"), but at the time I came up with twice that, somehow, some way...

http://gph.is/2iPNjr1

Yep, that must've been how.

*EDIT: No, wait a second, I divided that result by two, which is correct.  I suppose both will fit, but it would be too tight, I suspect.

Edited July 21, 2021 by Alan64

[Alan64]

The RA-worm assembly...

The nut required a 17mm socket...

...but I'm going to have to make a tool to loosen the adjuster.

Edited July 21, 2021 by Alan64

[Alan64]

Two 10d galvanised-nails into oak, and spaced 11mm apart...

The nails cut down to where 15mm lengths were left...

Then...

I just want to see if I can "fix" it.

Edited July 21, 2021 by Alan64

[Alan64]

The RA-worm assembly, exploded...

Not much else there, than what may be seen when assembled.

The ball-bearing assemblies fit quite well within the worm-block...

...good thing, that; although, nasty little hole there in the casting.

Hmm...

We can't have the two, steel ball-bearing assemblies rubbing against the brass worm, can we?

What might be done about that?

 

[Alan64]

More bronze "jewellry" for the mount-head...

[Alan64]

The washers do not span the full diameter of the ball-bearings, only a bit beyond the inner portion which rotates independently...

[Alan64]

The four worm-washers, two for the RA-axis, and two for the DEC-axis, are completed.  Glamour shot...

[Alan64]

The time has come to grease the worm-assemblies...

"Get on with it already!"

Okay, okay!

[Alan64]

First things first; firstly, the two ball-bearings of the RA-worm assembly were saturated with grease; the grease massaged, pressed into the bearings in the hope that some might make its merry way inside same...

Next, the cavities for the bearings were greased, and one of the bearings pressed into place...

The worm was washed, then greased, along with the bronze washers...

The threaded adjusting-sleeve was screwed in until it just stopped, by hand, no tool, then the nut was tightened over that...

  

The RA-worm assembly installed...

Whilst twisting the worm-shaft with the thumb and forefinger, the motion is utterly smooth and effortless, as though it's not attached to the axis at all, yet the worm-gear rotates at the same time, just as smoothly and effortlessly.

In that the bronze washers cannot be seen after assembling, there's no image of those to show, only of which to tell.

I will need to tweak the RA-worm assembly, with the set-screw in the centre of the block.  When taking hold of the worm-gear assembly, I can move same side to side only ever so slightly, left to right, right to left.  I want to see if I can get that just a wee bit tighter, without compromise.

The DEC-worm assembly, the cavities for the ball-bearings, are tighter.  It did not arrive as freely turning as the RA-worm assembly, but it's now just as the other.

Edited July 23, 2021 by Alan64