Renovation of a Manual EQ5-class Mount

[Eldest_Sibling (Alan)]

I can't use a go-to mount, whether an alt-azimuth or equatorial. I have too many trees here upon the lay, although I do have access to most parts of the sky, through gaps, "portals", between same.

Only the northern part of the night sky is quite, rather, illuminated, and by a large city 25 miles or so away, but I do have a very nice, and useful, view of Polaris, the North Star, nonetheless...



I like to observe the star on occasion, as it doesn't move.

There is also a considerable entertainment-venue to the west, about 10 miles away, but it's not nearly on the scale of a city; more like a small town. Just as well, as that's where everything sets.

The view to the east, where most everything rises, is free of light-pollution, as is the the southern view, save that of a neighbour just across the road...



That's Orion hanging above those "insecurity" lights. I do not have such on my property, and no need.

My skies have been at about 4 to 5 on the Bortle scale, over the last 25 years, although it may be nigh to 6 these days, and most unfortunate.

I am a visual-observer, with eyepieces, only, but with the odd afocal-shot taken through an eyepiece on occasion. I do that to show those first starting out as to what they might expect in the way of performance with an entry-level telescope, like this long-focus(f/12.9) 70mm achromat...



Would that they did choose the longer-focus instruments, although I do have a few shorter. But I need a supportive mount for that endeavour, and now, I have one...



I got it for a song, also a dance, new old-stock, as a result of the fall-out after Orion(of California) acquired Meade last June, and from an eBay seller who has always seemed to be a liquidator for Meade products.

It is a Meade LX70 equatorial mount-head; identical to the Saxon EQ-5, the Sky-Watcher EQ-5, all three manufactured by Synta, and clones of at least the Vixen "Great Polaris".

The Meade mount-head compared to that of a Celstron CG-4(EQ3-class) that I had acquired in 2012, but never used...



The Meade did not come with a tripod, but that of the Celestron is identical. I may have to pull even more parts off of the latter for the former, but perhaps not, yet they'll be there if needed.

Then, the mount-head will need motorising, the RA-axis only. I do have one of these 9V-battery powered gear-boxes...

[Eldest_Sibling (Alan)]

Beginning at one of the lesser of the four axes, the latitude, or altitude, axis came equipped with four 0.020"-thick plastic washers to stabilise the union between the mounting-base and the mount-head itself...



Before beginning this mount-head's renovation, I first browsed through this article...

http://www.astronomyboy.com/cg5/

It made mention of my own in particular, but it dealt primarily with the Celestron CG5. My own is identical to the second-generation CG5 illustrated within the article, and equipped with ball-bearing assemblies for the RA-axis. Those were added to improve support for Celestron's larger telescopes, the company's Schmidt-Cassegrains specifically. Then, I have read that some, if not many, do not prefer ball-bearings within their mounts.

One thing that I have noticed, among practically all renovations of these mount-heads, is that during a renovation, and at their conclusions, the plastic washers are, invariably, reinstalled, returned to the head.

I knew, before the Meade LX70 even arrived, that the axes, and elsewhere, would be filled with plastic washers, from top to bottom; bad prospect, that, but one that might be corrected, enhanced.

The latitude-axis does not move, hardly at all, for once you set your latitude, that's it. Small adjustments may be made on occasion afterwards, however slight. Therefore, the plastic washers should do just fine, yes?

But not within my own; I ordered aluminum sheets, 0.040" in thickness. The final thickness, however, for each side of the axis, came out at almost 0.060", so in the end I had to use four washers after all, the other two somewhat thinner than the first two...



The increase in thickness resulted from removing the paint from certain areas...



...and in the levelling of same where needed, specifically the spokes...





...much improved.

[Eldest_Sibling (Alan)]

This, the very first GEM, or German equatorial mount, on the planet, the Dorpat...

https://i.imgur.com/3fCQwZW.jpg

Then, the Yerkes GEM...

https://i.imgur.com/4zpIsAE.jpg

I think it's safe to say that neither one of those equatorial mounts contained plastic washers.

Of course, compared to those two, my own is most insignificant. But we do manage to do what we might.

I felt that it was best to separate the two axes, then to work on them one at a time...



Firstly, the axes needed the factory glue-grease, high-viscosity, cleaned out, then the parts of each inspected, and sized-up for what was to come. I began with the RA-axis. Both axes have an aluminum lock-nut, disk-like, solid, that keeps the parts within from falling out and apart onto the floor...



The one for the RA-axis has three set-screws. Those must be loosened, backed off, and before unscrewing the lock-nut...



The two holes at the front of the nut, circled in green, are used to unscrew same. I made a tool for that, of oak and galvanised 4d nails...



The set-screws of the lock-nut are accessed through this hole, and as the axis is slowly rotated, one screw at a time...



It's off...



We then see the first of the ball-bearing assemblies, which consists of the ball-bearing ring itself, with two enclosures...



After removing the lock-nut and the ball-bearing assembly, the RA-axis may be taken apart.

[Eldest_Sibling (Alan)]

The RA worm-assembly was removed and set aside. This was done by removing four screws; but not the black centre-screw, as shown...



This might be done before removing the lock-nut.

Let's have a pull-apart, shall we...



There they are, the two plastic washers, and to be discarded, but not before the thickness is measured. It doesn't matter as to the inner and outer diameters, as those will be measured elsewhere.

This, the primary ball-bearing assembly within the RA housing...



I use charcoal-lighter fluid, the type used for grilling food outdoors, to remove the factory-grease. It works a charm...



The parts for the RA-axis cleaned and de-greased, and ready for the next step...

[Eldest_Sibling (Alan)]

Atop the DEC-axis is the Vixen-style saddle, and for my telescopes, large and small. It and the worm-assembly were removed first...



Incidentally, the DEC worm-assembly is identical to that of the RA-axis, hence, the two are interchangeable.

It was a long, hard road leading up to the bottom of the DEC-shaft...



Its lock-nut has only two set-screws to back off before unscrewing. Note the plastic washer; history. The setting-circle has two of those, much thinner than all of the others, mired in the only instance of glue-grease that I uncovered throughout the entire mount-head, I'm happy to report, and they're for it as well.

Throughout the mount, otherwise, the grease used by the factory is very much like what I use to re-grease, but I cleaned it all out anyway. Did Synta finally get a clue?

What might we find here, within? I'm almost afraid to look...





More plastic washers, when will it end; drat. Oh, it has ended. What a relief, no more to be discovered.

The DEC worm-gear is shorter than that of the RA-axis; for reference.

The components of the DEC-axis were cleaned, de-greased, and stowed away within their own special, little box...

[Eldest_Sibling (Alan)]

The mount-head is of aluminum, totally, including the axes's shafts, save the screws(steel), the worms(brass), and the ball-bearing assemblies(steel).

Incidentally, I found no metal filings or shavings, swarf, within this mount-head. Not a single bearing-surface was painted, either. All surfaces were mirror-polished, at the factory, as seen; even some that do not contact another. In other words, all of the parts are ready to be re-assembled, and with this...



...Super Lube, a PTFE(Teflon)-based grease.

I've had that canister for quite some time, tried and true. I did consider, for this mount-head, an alternative, having purchased it soon after the mount-head arrived...



...Lucas Marine, a calcium-sulfonate grease. It's blue, and like the accents round and about the mount-head. But no, that's not why I chose it.

The two greases compared...



However, I decided in the end not to use the Lucas Marine. It is an unknown, to me. I can use it for other things, for that various and sundry, but not for this mount-head.

But before applying the grease to this part and that, I like to make special little things for my mounts, things that might've, should've, been included, from the factory, but as we know they're not going to provide them.

The Bronze Age...

https://imgur.com/BeItYH6

Bronze hasn't been widely used for tools and weapons for about 3000 years. We're in the Iron Age, now. Some say that that's to be the final age, but who knows. The Earth is awfully deep. There might be something better down there, than iron. But then, iron has been brought to Earth from space, and on the backs of meteorites, so maybe that's going to be it after all. Somebody up there might be trying to tell us something.

Then, it has been said that when bronze is placed into machinery, it oft outlasts the machinery itself. I like that, a lot.

I've had this Grizzly G1257 scroll-saw, renowned among scroll-sawyers near and far, for many years, and during some of those the unit spent its time outdoors, exposed to the Sun, wind and rain. I finally brought it inside, and restored it. It wasn't damaged in the least, surprisingly...



It's of cast-iron, the frame, the table; and awfully, awfully heavy as a result. I can use pin and pin-less blades with it, the latter with this rather clever adaptor...



I can cut, saw, all manner of non-ferrous, non-iron or non-steel, metals with it, adroitly, or nigh enough to that of government work. I also use small and large metal-cutting shears in crafting my creations.

Up until recently, I had been using 0.008" -thick phosphor-bronze, and 16 times thicker than Wal-Mart's "Great Value", household, aluminum foil, at 0.0005" in thickness...



I used it for my Celestron(Synta)EQ-1, sintered(powdered, oil-infused)-bronze items as well, and in addition to needle-thrust bearings, of steel. That mount has been completed.

Per Mohs scale of hardness, for metals...

Aluminum: 2.5 - 3
Copper: 2.5 - 3
Tin: 1.5
Bronze: 3
Brass: 3
Zinc: 2.5, same as gold
Brass: 3

I suspect that the "3" for bronze is probably indicated for the zinc-alloyed copper, which is used for arts & crafts/jewellery. I use phosphor-bronze, which is tin-alloyed copper, yea, and with the addition of phosphorus. If I had to guess, I'd say that a scratch-test would result in 3.5 to 4 on Mohs scale for phosphor-bronze. Steel is known to be at 4 to 4.5, but this phosphor-bronze seems to be softer. After all, it's of mostly copper.

There are also the Rockwell and Brinell scales to test the hardnesses of various metals, but the Mohs scale is easier for me to understand, admittedly. After all, I don't do this sort of thing for a living.

[croweater (Richard)]

Alan I believe we have left the iron age and are now in the "plastic age" 😕

[Eldest_Sibling (Alan)]

Originally Posted by croweater

Alan I believe we have left the iron age and are now in the "plastic age" 😕

Yes, Richard, that does sound plausible.

[Eldest_Sibling (Alan)]

The main plastic washers of the RA-axis had to go. I'm certain that they slide ever so smoothly over the surfaces with which they come into contact, but I want them out, no ifs, ands, or buts.

The two plastic washers are 0.020" in thickness, a fiftieth of an inch. That meant that I could not use the 0.008" bronze. So, I ordered a roll of the 0.020"...



When I cut the band holding the roll together, the roll unfurled in a split second, and violently. I then cut out what I needed.

Glamour shot <Look this way, my darling! No! Not that way! This way!>...



It's all about circles, you know, like whilst collimating a Newtonian, rotating an axis, the Airy-disk of a star even, not to mention its whirling, razor-sharp diffraction-rings, but I mentioned it anyway. Hence, I needed a compass...



The one on the left won't do, and one I've had for years. So I went out to my local hardware and what-not discount-store, and got the one at the right, a 6", in length. They had a 12", too, but I passed. It's of tool-steel, utterly, and the tips of the legs are very sharp. Indeed, a point serves as a scriber in its own right...



Not once did I have to fill its holder with a scriber-pen. I got one of those, too, at another hardware store, just in case. I have used it for describing marks, however.

Instead of measuring the plastic washers for their replacements, I made measurements per the axis's parts themselves, and with this...



The primary-washer, at the teeth of the worm-gear...



...and the other, secondary-washer, at the bottom of the worm-gear...



The odd measurements may be rounded off, but not always. There were times when I had to adjust the measurements, but always slightly, either larger or smaller. Indeed, the replacement washers are oft "scuplted" to their final diameters.

[Eldest_Sibling (Alan)]

The replacement washers were described onto the 0.020" bronze, using tiny pilot-holes drilled in the centres for the compass-point...



But what are those other, smaller circles, there within the centres of the larger? Could they be replacements for these...



Indeed, they are...





...waste not, want not.

Incidentally, those original enclosures for the ball-bearing ring are also 0.020" in thickness. Curiously, they are only weakly attracted to a magnet. They're not aluminum, no, but perhaps an alloy-steel? Your guess is as good as my own. In any event, they are O so historic.

Sawing out the washers; I broke several blades in the process, and with this thicker phosphor-bronze...



Note the pilot-hole drilled for the scroll-saw's blade, as well.

It is most important to never saw the inner diameters of these washers right on the described line, but before the line, one or two millimetres should be ample, and for fine-tuning the diameters afterwards. This can be important for the outer diameters as well, whether by sawing or using the shears. My goal was somewhat rough cut-outs, not those precise.

[Eldest_Sibling (Alan)]

Understandably, the first thing that might pop into one's mind is why I didn't use a metal-lathe to make these washers. I do have one, a small one, but I've never used it before, and it needs restoring, too. Also, I would need to buy certain items for the operation, and ones that I would need to research first. The scroll-saw and the rest are working quite well for this, so there's no hurry for the lathe's restoration. Then, I may never need to do this again, after all, unless I get a manual EQ-6 in future, which is a most probable impossibility. I blame light-pollution for that.

After the washers were sawn out, again, roughly, they have to be fine-tuned. The primary RA-washer, again, where it meets the toothed end of the worm-gear and the primary, forward, sealed ball-bearing assembly, should not extend over the teeth of the RA worm-gear...



I can see all of the teeth, all the way round, and that's the way it should be. This ensures that the washer will not interfere with the worm and gear meshing together. Admittedly, it is more of a good practice, perhaps my OCD instead, than an actual concern.

I use a Dremel rotary-tool to dress these washers to their final diameters. I use bits like these as well...



But with the grinding-stone, at right, that one tends to build metal up at the edge being ground, which has to be removed afterwards with a diamond-bit. The sanding-drum doesn't do that, hardly at all. It does depend upon the pressure applied whilst sanding. I use the sanding-drum exclusively now, although they don't last as long as the stones, and whilst bearing against this bronze.

After a washer is dressed, the inner and outer edges are sanded, with progressive grits, 100 to 220, then polished with #0000 steel-wool and lemon-oil...



"Holloway House" lemon-scented furniture-oil; I've had that bottle for many, many years, twenty or more. I would never use it for furniture, no, not ever. I use it as a machine-oil instead, and it works great, as it contains petroleum distillates. Don't put petroleum on your fine furniture. Also, "Old English" lemon-oil is the same, so beware. Then, I may need to get a bottle of that when my "Holloway House" runs out. I'm always working on something or other.

[Eldest_Sibling (Alan)]

The primary RA-washer continued; for the inner diameter, I had to make certain to clear the very edge of the sealed bearing. Its bevelled, sloped edge is slightly higher than the rim surrounding it, and easy to miss...



To slightly enlarge any inner diameter, I hold the washer in my hand whilst lightly rolling the sanding-drum round and round. I have done this for the outer diameters as well.

Glamour shots of the completed primary RA-washer...





The washers, during their craftings, are invariably very-lightly scratched here and there, yet in the end are smoothed with the fine steel-wool and lemon-oil. After the grease is applied, they effectively disappear.

Test-fitting...



That, yea, that is where the Earth stands still.

[Eldest_Sibling (Alan)]

The secondary RA-washer has a problem, but not with itself...



Incidentally, that is not a gouge into the washer's surface, rather only an abrasion, a "polishing" of the surface.

No, the issue is with that part of the axis instead...



Note the very narrow ledge where the washer is expected to rest. SYNTA!

The surrounding area can be filled with an aluminum washer, then the bronze washer on top of that, and for extra support. However, I feel it would need to be at the exact height of the ledge, but perhaps not. In any event, I didn't bother. I can always return to that, if there's ever a problem.

It is for that very issue that the inner-diameter of the washer must be roughly determined, then carefully enlarged to where it just slips over the worm-gear's drum...



I wanted that washer resting over as much of that narrow width as is practically possible. It is quite snug, but will rotate freely if required.

I could not saw out any of these washers, precisely, and expect them to fit without adjusting, perhaps not even with a lathe. That's not going to happen, not with my dubious, suspect set of ISO 9001 "standards".

But where are the smaller washers, and for the secondary ball-bearing ring? They were cut out of the same sheet of bronze. Ah, here they are...



I made two shims, of the thinner, 0.008" bronze...







...and for the inner-diameter of the ball-bearing ring, as I don't want the inner edge of the steel ring rubbing against the threaded, aluminum portion of the RA-shaft that it will surround. In addition, I don't want the ring to oscillate as it rotates. That's called having two birds in the hand, instead of just one, and with the other in the bush.

The two washers for the secondary ball-bearing ring differed from one another somewhat, and per these measurements...



At left, the inner-diameter of the lowermost washer is about 1mm larger than that of the uppermost. The red line denotes the division of the inner and outer portions of the RA-shaft. At right, the lowermost must be able to drop into the well, as indicated. The uppermost might need to as well, therefore it's best to simply have both with that ability.

[Eldest_Sibling (Alan)]

The worm-blocks of both axes...



They are identical to one another, and, again, therefore interchangeable. But I kept them separated nonetheless. I did not end up placing the RA worm-block onto the DEC-axis, and vice-versa. Although, I do suspect that there's a huge container of these blocks on the factory floor, and to be dipped into when needed for either axis.

One thing I noticed about these assemblies, prior to disassembling, is that they contain no washers, zero, zippo, nada, none that I could see.

That's a terrible shame, as I love to fill my mounts with all manner of bronze washers and needle-thrust and/or ball-type bearings, whether they need them or not. No, that's not true, of course, but I do place them where I think that they will do at least some good, with the performance, perhaps, better than before, but only after having inspected the areas, in relation to one another even, first.

A worm-block, exploded...



Nope, not a single washer to be seen.

That nut required a 17mm socket; gads. I also made a special tool, like the others, but extra special, and to adjust the threaded tensioning-sleeve...



But for these worm-blocks, I'm not certain if it would do them any good, but I did it anyway...



...two for each worm-block. I took care of both at the same time...



The washers lay within the outer, slightly taller rims of the mini sealed-bearings...





Can't have those steel bearings rubbing directly against the brass worm. I made buffers for them.

[Eldest_Sibling (Alan)]

The time came, at last, to re-assemble the RA-axis...



All surfaces that touch one another were 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...









Only one shim for the secondary ball-bearing ring was used, and sufficient...





The lock-nut was screwed on until it stopped, then backed off about 1/6th of a turn.



There it is, the secondary RA-washer, perched on its narrow ledge, as seen through those four holes at the front of the axis, and seemingly forever to haunt me.

[Eldest_Sibling (Alan)]

Incidentally, as the mount arrived in two boxes, one contained these parts(including those for the axes's clamps, or clutches, and the parts for the RA setting-circle assembly, which had been removed from the mount-head prior to packing)...



I've accounted for all of the parts that should've been included, and they're all there.

The components for the RA worm-block were greased and assembled...



The worm was then attached, and adjusted.

The worm now turns ever so freely and smoothly, as though it's not attached, connected to the worm-gear. Then, the forward portion of the axis's rotations are butter-smooth, easy to rotate. No slop or binding whatsoever with either. It's quite incredible, particularly when compared to when the mount-head first arrived...



Success!

But then, the RA clamp hasn't been installed, nor has the DEC-axis itself, so I'll tone down my excitement for now.

[Eldest_Sibling (Alan)]

Now that the RA-axis is completed, I may now begin to renovate the DEC-axis.

The DEC-axis had no ball-bearings or other within itself at all. What a pity, that. There's really no place within the axis to add a ball-bearing assembly, sadly.

In advance, however, I had ordered a 30mm x 47mm x 2mm needle-thrust bearing to grace the very bottom portion of the axis...



But I could only snap it into place, and then dig it back out, initially, as shown.

So, I removed the paint from the well's wall, ground down the wall a bit all round with a cylindrical diamond-bit, polished the surface, and until the bearing spun round freely...





...and with that tooth-pick. For the inner diameter of the bearing, I could not add a shim, like I did for the RA secondary ball-bearing ring, so instead I buffed, smoothed the threaded portion of the DEC-shaft that it would surround. The needle-thrust bearing will be sandwiched between two thicker, 0.020" phosphor-bronze washers as well.

Alas, I could not place the bearing where it really needed to be, and on the opposite side, within the DEC-housing...







...as it would throw everything off from there on up; pity, that, as well. The bearing seats rather nicely there, as you can see, but it was not to be.

[Eldest_Sibling (Alan)]

The specs for the primary DEC-washer...



Note yet another narrow ledge there, but one that cannot be helped.

That for the secondary...



...and that for the two washers for the needle-thrust bearing...



I cut off a second portion from the roll of 0.020" phosphor-bronze...



Again, just like I did for the RA-axis, I marked the centres with an X and drilled a pilot-hole for each with that teeny-tiny carbide drill-bit...



...then described the four washers for the DEC-axis, the primary and secondary, and the two for the needle-thrust bearing...

[Eldest_Sibling (Alan)]

Unlike for the RA-axis, for the DEC-axis I will show more details of the process in the crafting of these washers...



Again, I did not saw precisely at the described lines...



...and so to tailor them there at the parts of the axis.

Here, the primary DEC-washer has been dressed with the sanding-drum, but not yet paper-sanded and polished...



I was in earnest to see how well that one would fit after dressing, and due to its placement upon its narrow ledge, so I took the time to take photographs.

Here, the primary washer has been paper-sanded and polished...



Again, the primary washer does not protrude over the teeth of the worm-gear, all round.

[Eldest_Sibling (Alan)]

I dressed the secondary DEC-washer with the sanding-drum, but, initially, it would not drop down into the DEC housing. It was a bit befuddling, "What happened???" But, here it is, completed...



The inner diameter was correct, but I had to reduce the outer diameter, considerably. I had described the outer circle accurately, yes. That was the primary instance where I had to lightly apply the sanding-drum, to "sculpt", round and round the outer diameter, several revolutions -- that French, then that Russian -- until, at last, it dropped into the abyss.

This is an example of where I use shears to dress the outside diameters, in this instance of the washers for the needle-thrust bearing...





...and roughly shaped. There, the inner diameters had already been completed.

Then, the outer diameters here, after the sanding-drum, paper-sanding and polishing...



Incidentally, this is what I'm replacing with those, and ill-fitting...



Yea, just enough to get by, just enough to get it out the door and onto the seaborne container.

The total thickness of the needle-thrust bearing and its two bronze washers is 0.122", almost twice that of the plastic washer being replaced, and negligible in the end.