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#26 dgreyson

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Posted 13 January 2013 - 08:44 PM

PM sent.

#27 turk123

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Posted 13 January 2013 - 08:55 PM

Datapanic

That link is for a 1/3 RPM motor. Did you mean the 1 RPM or possible the 2 rpm. Looks like they have a variety of speeds. Looks like a good source.

I will contact them tomorrow to check availability.

#28 Datapanic

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Posted 13 January 2013 - 08:58 PM


I think most of the Dec motors (either brand) were 1RPM, however a 2RPM or 1/2RPM makes a good substitute. I actually prefer the 2RPM because its slew speed, at least with the Tangent Arm Dec Controls seem to more closely match the speed of the Clock Drive running with a variable frequency control providing 40/60/80Hz. But, I have a different setup with a home-made dual axis frequency control box and one hand control so I can easily move in both axises if needed.


So what your saying is that there is a replacement motor that I could purchase as a replacement for the original? Do you have a link or part number for them?

That was my only fear in purchasing this one. The DEC motor was missing and possibly the mount for it. In leu of finding a cave motor, a new motor would work for me. I want to keep it as close to original as possible, but I will give that up for functionality. It is important for me to also use this as intended.

Turk


I don't know what kind of motor was provided with the worm-driven Dec control. Hopefully someone will chime in about that.

Regardless of the motor brand, they are out there, just have to hunt one down. I found the Hurst motor I needed on a surplus site here: http://www.aptecelec....com/prod03.htm Until you know what motor is needed and the part number, it's going to be difficult to track one down :)

#29 Datapanic

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Posted 13 January 2013 - 09:05 PM

CN Thread about locating replacement motors for Cave scopes

#30 PiSigma

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Posted 13 January 2013 - 09:30 PM

The motor is a Hurst Model CA series. The Hurst website shows that series as discontinued but maybe surplus is out there. I'm not sure of the speed.

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#31 PiSigma

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Posted 13 January 2013 - 09:31 PM

It looks like you have the clutch assembly and original motor mounting plate (sandwiched between the OTA cradle and support bearing). We can't see it in the picture but hopefully that manual flex cable is attached to the original worm gear and mounting block. It is hard to tell how the previous owner attached the flex cable. But the end cap, round cover sleeve, round motor mount and triangular motor adpater might all be missing. A machinist might be able to make these.

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#32 PiSigma

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Posted 13 January 2013 - 09:33 PM

My motor is connected to the worm by two toothed drive gears and joined by an internal toothed rubber sleeve. These might also be missing.

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#33 PiSigma

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Posted 13 January 2013 - 09:34 PM

The rubber sleeve.

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#34 turk123

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Posted 13 January 2013 - 09:48 PM

Here is a new picture;

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#35 PiSigma

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Posted 13 January 2013 - 10:01 PM

Here is a new picture;


OK, so the cable is attached to the same side of the worm where the motor would be coupled to, almost certainly with the original worm and block.

#36 turk123

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Posted 13 January 2013 - 10:06 PM

Here is a new picture;


OK, so the cable is attached to the same side of the worm where the motor would be coupled to, almost certainly with the original worm and block.


I hope that is good?? I just sent an email to Paul in NY to see if he would contact the original owner for the rest of the parts. I haven't heard back yet. I doubt he would have them.

What else can I do? Manufacture the rest? That certainly is an option.

#37 Datapanic

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Posted 13 January 2013 - 10:19 PM

Hopefully the original parts will be located!

April's too far from now - road trip!

#38 dgreyson

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Posted 13 January 2013 - 11:24 PM


You are missing the motor mount. So Bad. But not fatal.

Local machine shops can easily make the motor mount for you, Crawford Machining specializes in custom telescope parts.
http://crawmach.com/custom_work

The best bet, is to find the original parts if they arent lost. worst case, A stepping motor could be used instead of the original. That would be somewhat cheaper but requires technical expertise in electronics or the use of programmable logic controller chips. It's always preferable to keep a collectable object as original as possible, but Telescopes are meant to be used, So using substitutes to get it in proper working order is not the end of the world.

On the other hand, if you have a gracious wife or a girlfriend with moderately low standards, I'm confident they would surely jump at the chance to crank the thing around for you while you stand on your stepladder looking into it. Tell them William Hershells wife Mary and his sister Caroline also, were both glad to help out when he needed them. How could ones gentler half refuse if you were to put the question to them in a polite and gracious manner?

#39 turk123

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Posted 13 January 2013 - 11:54 PM

Thanks Dgreyson

I did find the flexible gear couplings. Here is the link:

https://sdp-si.com/e...sp?GroupID=1014

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#40 Datapanic

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Posted 14 January 2013 - 12:29 AM

Stock Drive Products is first rate! I've found a lot of parts there for various restores many times.

#41 turk123

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Posted 14 January 2013 - 07:52 AM

One more picture:

The optics were re coated in 2008.

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#42 turk123

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Posted 14 January 2013 - 08:34 AM

One more of the mirror. The business end.

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#43 RogerRZ

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Posted 14 January 2013 - 05:11 PM

Hi, I just wanted to pop in, and present myself as the owner before Paul. I regret to say I passed it on to Paul in the same condition and with the same parts I received it in. :( No spare parts...

Someone might be able to verify that these mounts are all like that, but this particular example looked a lot sturdier than it actually was. I have to say that the rotating rings and the slip clutches made it quite fun to use just the same...

Good luck to you!

#44 turk123

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Posted 14 January 2013 - 06:05 PM

Hi Roger

I found Roger through Paul and ask him to chime in here not knowing he would be dissing my mount! I'm at a disadvantage as the mount is not with me yet, but this "looseness" in the mount has me puzzled. What could cause that or are the mounts a bit loose to start with?

Thanks for coming Roger!

Turk

#45 Datapanic

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Posted 14 January 2013 - 09:05 PM

Adding a latitude adjuster to the Cave mount will help make it much sturdier. Otherwise, the entire weight of the OTA and Equatorial head pass through a single point - that bolt on the pier cap that connects to the RA Shaft Housing. Through my own testing with the 8" Lightweight Deluxe I have which also has a latitude adjuster, when that bolt is tight, it takes quite a few seconds (>5) for vibration to dampen out when the tube is touched. But, when that bolt is loose and the weight of the OTA and head are divided between the bolt and a latitude adjuster, dampening takes less that a second! The tighter that bolt is, the worse the dampening time gets.

The other cause of wobbliness are the caster wheels - but that can be alleviated by removing them or using leveling bolts, if equipped.

Not sure if that's the looseness you're talking about, but thought I would mention this anyway for the Shop Talk on Caves :)

#46 turk123

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Posted 14 January 2013 - 09:24 PM

Thanks Datapanic

Both past owners have mentioned the looseness in the mount. Again, I have no way to look at or test your ideas, but I am filing all this away to address later. I need to go get this thing . . .

The trouble with going to NYC with my wife will be that SHE gets to shop and spend as much as I did on the scope. The cost of this hobby never is fully measured unless you include that extra cost. :lol:

#47 Datapanic

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Posted 14 January 2013 - 09:36 PM

I hear ya - my gets a Victorian era dress with accessories for every scope I get, so I choose carefully!

#48 turk123

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Posted 15 January 2013 - 08:03 PM

Well, I have a source for the motor (abet new), I also have the 2 gear flexable coupler, and I just talked to a friend of mine who has a lathe, We can make the two parts I needed. Those are the two parts mounted to the motor in the picture below..

When the time comes, is there anyone out their with a micrometer that could measure the two parts? Possible trace and scan them also? That would make it so much easier than trial & error (and mostly error)! It just has to be close as we can make them line up to fit the worm drive when it gets mounted to the worm plate.

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#49 PiSigma

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Posted 15 January 2013 - 10:37 PM

Tom,

I can do that, just need to remember to bring my mic home from work. I'll try and take mine apart and do some drawings this weekend. Here's another shot from when I restored mine. As you've probably noticed the round cover and end cap aren't needed to make it work. They just cover up the mechanism.

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#50 turk123

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Posted 15 January 2013 - 11:02 PM

Thanks Jon

I see that those are not necessary, but then, it wouldn't be a cave.

I appreciate your help.

Could you also measure the flexible gear coupler? I need to know what size to buy. Gear size and assembly length.

Thanks so much! I was hoping you would chime in. After all, you are an engineer!






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