A Restoration

[Alan64]

The first thing that popped into my mind when thinking about how to go about cutting the brass rod square and true was my trusty Sears Craftsman 4" drill-press vise...

That vise was a great buy at the time, new old-stock, and for US$50.  I just spent about two hours cleaning it up.  I had left it out of its box, and it became fouled with rust and other.  It's now back to its old self again.

Now to decide what to do next...

[Alan64]

I took a hack-saw, with a special metal-cutting blade, and used the drill-press vise to square the previously-cut(by the seller or other) end...

It's okay, for government work.  But then it dawned on me.  Why don't I use my miniature, Preac table-saw instead...

I got that table-saw years ago, and with largest-table option available.  Sadly, it is no longer made, and parts for it are as scarce as proverbial hens' teeth.  But where there's a will there's a way, if the need arises.

Before sawing the rod for the "buttons", I will want to sand the rod in that area down a bit, and to ensure a good fitting.  

[Alan64]

The original black-plastic "buttons" are 5.08mm in thickness.  Let's just round that off to 6mm, shall we...

[Alan64]

The first "button" was sawn, and at 6mm in thickness...

However, I decided to discard that one.  I then set the thickness at 5.5mm...

All that glitters, is gold, albeit a fool's gold...

[Alan64]

Aren't they lovely? 

The clamp-bolts were dirty.  The one on the right is still fouled with the factory-grease...

Whilst clamped, the axes are immovable, even when pressure is applied; success.  However, I am mindful that I've yet to put the mount-head into practice, and with one of my heaviest telescopes attached...

Time will tell.

[Alan64]

<gasp> The DEC-axis is upside-down...

Juuust look at it...

That's one sorry assembly, the DEC setting-circle.  It's reputedly ineffective, and its execution is deplorable.

The clear washer there is 0.0125"/0.32mm in thickness, and fits underneath the setting-circle, and on top of the DEC lock-nut.  That's the only location within the entire mount-head where I found factory glue-grease.  The RA setting-circle, no doubt, is saturated with it, too.  The glue-grease is used, wait for it, to compensate for hastily and poorly designed assemblies.

In that I might actually try to make use of it, it will need, not one, but two washers of the thinner bronze, one on each side of the circle.

[SpookyKatt]

Can I ask Alan, are you planning to motorise the mount when your finished ?

Kathleen

Edited July 31, 2021 by SpookyKatt

[Alan64]

20 minutes ago, SpookyKatt said:

Can I ask Alan, are you planning to motorise the mount when your finished ?

Kathleen

Indeed, and with this...

https://www.firstlightoptics.com/celestron-astromaster-series/motor-drive-celestron-astromaster-geq-93514.html

I got it for my EQ-1 and EQ-2, but it looks like its very first use will be with this Synta EQ-5(Meade LX70).

Incidentally, it has been done before, and successfully.  I will need to be creative in its attachment however, and possibly with wood.

Do you have mounts that are motorised?

The last time I used a motorised mount was back in the early 1990s, and with this Parks Optical EQ-2(made in Japan)...

I watched Venus from about 5:30 in the morning whilst it was still dark, and until almost noon.  It was wonderful, and I'm wanting to experience that again.

Edited July 31, 2021 by Alan64

[SpookyKatt]

I do use mounts that are motorised, I used to have an EQ5 to which I added the synta motors and
have to say it worked very well except for breaking the cable at the battery box and the times the clutches
would loosen and I would wonder why jupiter was zooming out of the eyepiece.  I think its a great upgrade
to the EQ5 I have to say and always worth doing.

I was just wondering how well it will all work with the motors, i can't see it not working but I guess i was wondering
will it work a little too well now and race so to speak given your work has resolved the majority of the design
and manufacturing issues.  

Interesting though that you are going to use the motor for the EQ1 and EQ2, will that work with the EQ5 ?  I mean
presumably thats been made to work with those mounts and they presumably have a different and
probably simpler worm mechanism with a different ratio.  So won't that motor 'tick' at a rate that may mean
the mount doesn't cope with sidereal rate and maybe goes too slow now ?

Edit: Sorry I just seen that you said in your post that this has been done before, apologies I didn't see that the
first rime I read it, you can ignore my questions.

Kathleen 

Edited July 31, 2021 by SpookyKatt

[Alan64]

10 hours ago, SpookyKatt said:

I do use mounts that are motorised, I used to have an EQ5 to which I added the synta motors and
have to say it worked very well except for breaking the cable at the battery box and the times the clutches
would loosen and I would wonder why jupiter was zooming out of the eyepiece.  I think its a great upgrade
to the EQ5 I have to say and always worth doing.

I was just wondering how well it will all work with the motors, i can't see it not working but I guess i was wondering
will it work a little too well now and race so to speak given your work has resolved the majority of the design
and manufacturing issues.  

Interesting though that you are going to use the motor for the EQ1 and EQ2, will that work with the EQ5 ?  I mean
presumably thats been made to work with those mounts and they presumably have a different and
probably simpler worm mechanism with a different ratio.  So won't that motor 'tick' at a rate that may mean
the mount doesn't cope with sidereal rate and maybe goes too slow now ?

Edit: Sorry I just seen that you said in your post that this has been done before, apologies I didn't see that the
first rime I read it, you can ignore my questions.

Kathleen 

Not at all, for I love to answer questions, or to at least elaborate upon them further.

The wee motor-drive has a speed-control, a varistor, which will compensate for any discrepancies...

Would that all motor-drives had a speed-control.  I'm a bit leery about acquiring a drive with a hand-controller, unless there's some way, somehow, to add same.

Hmm, you mentioned that your clutches loosened.  I have to wonder if I've eliminated that possibility with the brass clamp "buttons".  In addition, they are somewhat larger, and will not compress.  Time will tell.  I may even have to tighten up the axes, albeit slightly; the RA-axis in particular, for as I was rotating the axis with the worm, with the head on the tripod, I detected a bit of shuddering.  Of course, there was no telescope, or counter-weight, attached.

[SpookyKatt]

Yeah when I re-read your post and looked at the motor I seen what you mean re the variable speed
control, interesting that it would work with the EQ5 but fair enough.

Well when I said clutches I was not meaning the locking clutches, with the EQ5 motor kit the
transfer gear (not sure thats its name) that attaches to the slow motion control has a clutch mechanism
allowing you to 'disconnect' the motor and use the slow motion control (shown with the red arrow).  Its
engaged and disengaged mearly by tightening loosening the silver knob.

   

I just found that sometimes it would slacken perhaps due to temperature or something.

Edited July 31, 2021 by SpookyKatt

[Alan64]

Ah, I see.  That's the same type of motor-drive kit that I had been looking at, but for the RA-axis only.

Now, at present, the worm of the RA-axis rotates ever so freely and smoothly.  I don't know if that will change, hopefully not by much, once a load is placed.

 

[Alan64]

This 0.008"/0.203mm thick bronze snippet from the sheet has its Xs...

Those will be the two washers, the smaller at 28mm x 35mm, the larger at 26mm x 40mm, for the DEC setting-circle assembly.

[Alan64]

I was thinking that I was done with making these bronze washers.  It's gruelling work, but I certainly didn't mind doing so for the axes, as I was on a mission, and one accomplished; but for these setting-circles, really?  The washers are ready to have their inner-diameters sawn out...

Perhaps they'll take the sting out of actually using them to try to find something.

[Alan64]

The washers have been sawn out, and dressed to fit...

Now to polish the inner-diameters before cutting them out from the sheet.

 

[reezeh]

On 30/06/2021 at 13:25, Alan64 said:

Thank you.  I suppose, if I sat my mind down to it, I might manage an alt-azimuth; but heavens no, not an equatorial.

I think you can do it. An equatorial is just an altazimuth with added tilt! Oh and a bit of balancing. 

I know I am oversimplify it but essentially that's all it is.

My point is, I think you have the skills and experience to do it, even if you can't face it. 

[Alan64]

1 minute ago, reezeh said:

I think you can do it. An equatorial is just an altazimuth with added tilt! Oh and a bit of balancing. 

I know I am oversimplify it but essentially that's all it is.

My point is, I think you have the skills and experience to do it, even if you can't face it. 

Thank you ever so much, Robert.  I appreciate your faith and trust in my abilities, but I would not need to produce an equatorial in the first place, as I have this one, and for a lifetime.

In addition, do you realise what I would need?  For one, a $50,000 gift-certificate from this online-vendor...

https://www.grizzly.com/

...not that I'd really need that much.  However, it's not likely that they'd give me one for free, just for being a good fellow.  Then, there's the metal stock to consider. 

Indeed, you can convert most any equatorial into an alt-azimuth, including the one I'm detailing.  You simply extend this part outward...

Then, there's this...

https://www.firstlightoptics.com/skywatcher-mounts/skywatcher-az-eq6-mount.html

...and proof of the Janus-complex that exists between the two types.

[Alan64]

Now, that's the way it should be, nice and smooth.  It's a shame however that I did all of that for a piece of useless fluff, but we'll see if I have to eat crow some day.

Incidentally, I found the other on the floor.  It turns out that there were originally two of these embedded within the glue-grease on the underside of the setting-circle...

...and for a total thickness of 0.026"/0.65mm.  But why wasn't one on top of the circle and one underneath; why both underneath?  Do I really have to ask?  

In any event, the two bronze washers that replaced them are a total of 0.016"/0.41mm, but then I did add the thicker bronze washers along with the needle-thrust bearing under the DEC lock-nut, so it balanced out I suppose.

[reezeh]

This is an engrossing read 👍👌

Literally chronicling a labour of love

Are you sure you weren't a watchmaker in a previous life? 

I think the only pieces of kit you're short of are a lathe and a laser-cutter to precision cut out things like the washers. It won't surprise me if you have a lathe though. 

[Alan64]

20 minutes ago, reezeh said:

This is an engrossing read 👍👌

Literally chronicling a labour of love

Are you sure you weren't a watchmaker in a previous life? 

I think the only pieces of kit you're short of are a lathe and a laser-cutter to precision cut out things like the washers. It won't surprise me if you have a lathe though. 

I have this one, and purchased about twenty years ago...

https://www.grizzly.com/products/grizzly-7-x-12-mini-metal-lathe/g8688

...but it's fouled at present, rust mostly, and will need a nigh-complete restoration, if such is possible at this point.

I'm not aware of having once been a watchmaker.  I do directly descend from Benjamin Franklin's eldest brother, if that helps.

[Alan64]

I made a mistake...

The brass "buttons" are too thick, perhaps even the original black-plastic ones, as the brass ones are only slightly thicker.  There are built-in stops on the head for the two black clamping-levers.  The levers still did not go past the stops, but just barely.

I'm going to make two more, and this time at 4mm in thickness, 1mm thinner than the originals.  

I was able to rattle out the brass "button" for the RA-axis, but the DEC proved more difficult, and how.  In the end, I used five-minute epoxy, and attached a toothpick to it...

Incidentally, when duplicating a metal part, not necessarily for this mount, and with plastic or wood, the part generally has to be made larger or thicker to maintain the strength of the original part; wooden spoons are larger and thicker than metal ones, for example.  This, however, does not apply to all man-made, metal articles and instruments.  

But in this case, I did it in reverse.

[Alan64]

Waiting, or rather being forced to wait, for night-fall...

This time round I'll be sawing outdoors, upon the saw-horses, as the sawing of this brass rod produces a lot of "chaff".

[Alan64]

I sat the fence of the saw a frog's hair over 4mm from the blade, 4.10mm to be exact...

I certainly didn't want them any thinner.  They must be of some substance, else they'll compress and wear away into nothingness, not to mention leaving a mess behind.

They're awfully small, and now thinner...

Edited August 2, 2021 by Alan64

[Alan64]

The thinner brass "buttons" were dressed and polished...

Aren't they even lovelier, now that they're svelter?  

 

[Alan64]

The moment of truth arrived...

Success...

The DEC clamp-lever gets ever so close to its fitting, but not quite; in its hard-locked position...

Disappointingly, the RA-clamp, when unlocked, rocks back and forth a bit; slop, and has all along.  I was hoping that the thinner "buttons" would improve that, but no.  So, I took a piece of 0.005"/0.127mm thick aluminum sheeting, and lined the fitting's threaded cavity from top to bottom, halfway round.  I then screwed in the brass clamp-bolt all the way down, then out, and the shim conformed perfectly.  I then applied a liberal amount of grease to the fitting's and the brass bolt's threads...

I would've loved to have shimmed it with the slightly thicker bronze, but forcing the bronze to conform might damage the threads of the aluminum fitting, or the threads of the brass bolt, or both.  I'll play it safe for the time being.  That's something I would need to test, but not on this mount-head.  

The result?  In its unlocked position, the RA-lever does not rock in the slightest.

I don't think that the brass bolt, moving such a short distance, will chew up the shim over time.  But time will tell.

Edited August 2, 2021 by Alan64