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Royal Astro R74/Tasco 10TE - how to disassemble the mount?

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#26 LukaszLu

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Posted 23 December 2020 - 09:10 PM

This is not a shadow - three lines seem to be engraved so I think it must be a factory work... And yes - I meant the chipping that can be seen on far right, next to the spacer. There are two of them - really small, but it was enough to cover the whole space between lenses with glass debris!



#27 LukaszLu

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Posted 26 December 2020 - 12:49 PM

The final touches:

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#28 LukaszLu

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Posted 26 December 2020 - 01:04 PM

Well... and the final effect. This mount is a real work of art - amazing design! And the cover plate with five screws and the lock knob really rulez. It looks like an object from the S-F movie :-)

 

I had to add extra washers on both axles (under the RA cover plate and under the brass ring) to get the desired ease of rotation.

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Edited by LukaszLu, 26 December 2020 - 01:05 PM.

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#29 Bob Myler

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Posted 26 December 2020 - 03:12 PM

Excellent restoration and a gorgeous mount!

 

Now, will you please do mine? 😎


Edited by Bob Myler, 26 December 2020 - 03:16 PM.

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#30 LukaszLu

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Posted 26 December 2020 - 08:17 PM

Thanks Bob! If you undertake the repair of the my focuser in exchange - why not? ;-)



#31 Piggyback

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Posted 27 December 2020 - 03:25 AM

Just took delivery of my Royal Astro. Seems complete except for the metal? lens cover. I can see badly tortured reading circles and a tiny glas chip in the outer perimeter of the main lens. No visible cracks in any of the cast metal. Your detailed report will be a great help for my own restauration efforts!

 

 

IMG_4803.JPG

 

 


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#32 LukaszLu

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Posted 27 December 2020 - 06:50 AM

Congratulations! It is worth remembering that the fun of restoring such equipment does not necessarily have to be a means to an end, but it is an end in itself - it should be enjoyable, not stressful :-) My advice - disassemble the focuser and check the condition of the gears - there was an unpleasant surprise waiting for me here.



#33 Piggyback

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Posted 27 December 2020 - 12:14 PM

Just finished servicing my Royal Astro focuser assembly. No broken rail or bent focuser axle. Scraped off old grease and applied a fresh pack. Used automotive polish to make surfaces shine. Plan on taking care of wooden tripod tomorrow. 


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#34 LukaszLu

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Posted 27 December 2020 - 02:55 PM

Just finished servicing my Royal Astro focuser assembly. No broken rail or bent focuser axle. Scraped off old grease and applied a fresh pack. Used automotive polish to make surfaces shine. Plan on taking care of wooden tripod tomorrow. 

 

Lucky you! For now, I have no idea how to save my focuser.

 

I've already started the battle with the tripod... Removal of coloring varnish and regaining the natural color of the wood is not easy...

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#35 LukaszLu

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Posted 01 January 2021 - 06:16 PM

Work on the tripod is progressing. I decided to start by staining the wood with an oil-based and solvent-based stain. The wood will get quite dark, which should emphasize the age and class of the equipment :-)

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#36 Piggyback

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Posted 02 January 2021 - 01:57 AM

IMG_4814.JPG

 

Am I right your focuser rail is broken? If so you may want to ask this forum for a spare. People here are very helpful and I was lucky in the past to receive a replacement for my Weltblick 60/700 from CN member Barabino. 



#37 LukaszLu

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Posted 02 January 2021 - 07:37 AM

In my case, the problem is the distorted or broken rack elements. I cleaned the rack from dented metal fragments, applied a lot of thick silicone grease and the focuser works somehow. Sometimes you feel the unevenness when its moving, so I guess this damage will increase over time and the rack will degrade further.

 

Great idea - thank you very much, I will probably have to look for this type of help because my solution seems only temporary.

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#38 LukaszLu

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Posted 03 January 2021 - 09:05 PM

slowly reaching the end :-)

 

After covering the wood with an oil-based stain, I finally applied a furniture restoration wax to even out and soften the shine a little, making it satin and velvety. I don't know if you can see it in the pictures, but I like the effect very much. I can't wait to put it all together ...

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#39 LukaszLu

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Posted 04 January 2021 - 07:05 PM

Well, here it is... After almost a month of renovation work, it's time to sum it up. I am looking for the right word, but it seems I'm temporarily at a loss for words, so maybe tomorrow... ;-)

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Edited by LukaszLu, 04 January 2021 - 07:06 PM.

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#40 Garyth64

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Posted 04 January 2021 - 08:41 PM

Excellent job!  It looks brand new.



#41 LukaszLu

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Posted 04 January 2021 - 09:02 PM

Thanks a lot! In fact, it was not my goal to get a factory look, but the wood was so damaged that I decided to radically renovate the tripod. It is the wood that creates the novelty effect.

 

I wonder what is the real age of this specimen. Maybe someone can estimate it based on the serial number?

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Edited by LukaszLu, 04 January 2021 - 09:04 PM.

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#42 Piggyback

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Posted 05 January 2021 - 03:29 AM

Fantastic! So much attention to detail. Your meticulous work is inspirational. Did you get your focuser sorted? I started disassembling my mount. Serial number on focuser plate 870976 a mystery to me. There's been threads on this. From what I heard, second digit may indicate aperture class (76mm) but I could be wrong. CN member Stephen (stargoat) may want to chime in for clarification.

 

 

IMG_4833.JPG


Edited by Piggyback, 05 January 2021 - 03:38 AM.


#43 LukaszLu

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Posted 05 January 2021 - 05:59 AM

As for the focus, CharlieB has offered to help me and I hope the problem will happily be resolved. Thanks a lot Charlie!

 

The mount is somewhat disappointing, as it ran smoothly after cleaning and regreasing, but it begins to resist when fully loaded with counterweight and OTA. I mean mainly the RA slow motion mechanism. You feel some resistance when moving it, especially when it goes "up", you can also hear some shuffling  that directs my thoughts towards the red fiber seals... Perhaps this is due to the fact that the counterweight seems too light to fully balance the weight of the OTA.


Edited by LukaszLu, 05 January 2021 - 11:20 AM.


#44 CharlieB

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Posted 05 January 2021 - 06:41 AM

The eccentric bearings on these mounts are notoriously difficult to adjust properly.  Also, even a slight bit of excess tightening of the grub screws after you adjust the bearings can make a huge difference.  And as you found out, even when everything seems to be perfectly adjusted, when you add the counterweight and OTA, the slop or binding shows up. That's why I rarely use the original mount when I'm using the scope - unless it's for display.  

 

Charlie


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#45 Astrobril

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Posted 05 January 2021 - 08:45 AM

Thanks a lot! In fact, it was not my goal to get a factory look, but the wood was so damaged that I decided to radically renovate the tripod. It is the wood that creates the novelty effect.

 

I wonder what is the real age of this specimen. Maybe someone can estimate it based on the serial number?

The serial number, with the first digit being a '2' would suggest 1962 or 1972. The JTII sticker might help further, if it is still on the focusser or the tube. Other: if the cabinet is still present: if it has only wood it's 1962, if it has Styrofoam as well it is 1972. I have no other clue on how to fix the date between these. But some others are much more knowledgeable on this, so they might help. 


Edited by Astrobril, 05 January 2021 - 08:46 AM.

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#46 LukaszLu

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Posted 05 January 2021 - 09:35 AM

The eccentric bearings on these mounts are notoriously difficult to adjust properly.  Also, even a slight bit of excess tightening of the grub screws after you adjust the bearings can make a huge difference.  And as you found out, even when everything seems to be perfectly adjusted, when you add the counterweight and OTA, the slop or binding shows up. That's why I rarely use the original mount when I'm using the scope - unless it's for display.  

 

Charlie

I noticed that the entire head including the RA movement mechanism has a certain play, which contributes significantly to the formation of these resistances, which in some positions almost completely blocked the movement. If I support the head with my hand to compensate for this play, the mechanism starts to work much better.

Well - I disassembled half of the mount again to get to the two screws that hold eccentric bushings, which theoretically allows to adjust the free play on the RA axis. The problem is that no matter how much I tighten them, they turn out to be loose after a few turns of the knob.

 

I guess I'll just give it a rest and try to live with it, supporting the mount manually in critical situations. I think moving the slow motion knob to the opposite pin helped a bit - but maybe that's just an impression.


Edited by LukaszLu, 05 January 2021 - 09:36 AM.


#47 LukaszLu

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Posted 05 January 2021 - 09:39 AM

The serial number, with the first digit being a '2' would suggest 1962 or 1972. The JTII sticker might help further, if it is still on the focusser or the tube. Other: if the cabinet is still present: if it has only wood it's 1962, if it has Styrofoam as well it is 1972. I have no other clue on how to fix the date between these. But some others are much more knowledgeable on this, so they might help. 

Thanks! The cabinet has only wood, no signs of styrofoam in the past. The rubber/foam protections on the edges of the wood are completely petrified, so maybe 1962?

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Edited by LukaszLu, 05 January 2021 - 09:40 AM.


#48 CharlieB

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Posted 05 January 2021 - 10:22 AM

I noticed that the entire head including the RA movement mechanism has a certain play, which contributes significantly to the formation of these resistances, which in some positions almost completely blocked the movement. If I support the head with my hand to compensate for this play, the mechanism starts to work much better.

Well - I disassembled half of the mount again to get to the two screws that hold eccentric bushings, which theoretically allows to adjust the free play on the RA axis. The problem is that no matter how much I tighten them, they turn out to be loose after a few turns of the knob.

 

I guess I'll just give it a rest and try to live with it, supporting the mount manually in critical situations. I think moving the slow motion knob to the opposite pin helped a bit - but maybe that's just an impression.

Remember, there are four screws that hold the eccentric bearings in place and you can't tighten them too much, as they will cause binding.  They aren't meant to be tightened up so much - they are mostly to keep the bearings from pushing out from the sides.  I use just enough pressure on the screws to keep the bearings from moving. 

 

Charlie


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#49 CharlieB

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Posted 05 January 2021 - 10:23 AM

The scope is probably from 1962.


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#50 LukaszLu

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Posted 05 January 2021 - 10:35 AM

Remember, there are four screws that hold the eccentric bearings in place and you can't tighten them too much, as they will cause binding.  They aren't meant to be tightened up so much - they are mostly to keep the bearings from pushing out from the sides.  I use just enough pressure on the screws to keep the bearings from moving. 

 

Charlie

This is what I do with 2 accessible grubs - I only tightem them a little as I didn't noticed any effect on the free play problem. The same goes for the 5 screws holding the cover plate - they are tightened "to the first resistance" only. The hidden grubs however do have effect - if they are tightened, free play is smaller and the mechanism works better. I tightened them firmly, but not too much - they got loose very quickly however.


Edited by LukaszLu, 05 January 2021 - 10:46 AM.



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