Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Late 60s Cave 10" f/7 restoration project

  • Please log in to reply
67 replies to this topic

#1 tim53

tim53

    James Webb Space Telescope

  • *****
  • topic starter
  • Posts: 17,341
  • Joined: 17 Dec 2004
  • Loc: Highland Park, CA

Posted 03 December 2022 - 05:43 PM

And boy does it need it.  Good news is that there are two tube weight sets on this thing, a 2" Sky Micro Giant focuser, and a 360 degree Dec drive (though the Hurst motor likely is junk.  Fortunately, I've got a couple NOS Hurst motors somewhere in my shop)

 

 

Attached Thumbnails

  • Image (1).jpeg

  • gnabgib, Mr Magoo, Chris Cook and 9 others like this

#2 tim53

tim53

    James Webb Space Telescope

  • *****
  • topic starter
  • Posts: 17,341
  • Joined: 17 Dec 2004
  • Loc: Highland Park, CA

Posted 03 December 2022 - 05:44 PM

I'm just loading these pics as I'm pulling them off my phone, so the order doesn't make much sense.  That first one is me trying to loosen the latitude lock set screw.  It's pretty rusted in place, so will need a dose of penetrating oil.

 

 

Attached Thumbnails

  • Image (2).jpeg

  • Mr Magoo, Chris Cook, clamchip and 7 others like this

#3 tim53

tim53

    James Webb Space Telescope

  • *****
  • topic starter
  • Posts: 17,341
  • Joined: 17 Dec 2004
  • Loc: Highland Park, CA

Posted 03 December 2022 - 05:46 PM

The OTA, above, must be an f/7.  It's about 6 ft tall.  This shows the tube weight sets with 3 weights in attendance.

 

 

Attached Thumbnails

  • Image (3).jpeg

  • Mr Magoo, Chris Cook, steve t and 5 others like this

#4 tim53

tim53

    James Webb Space Telescope

  • *****
  • topic starter
  • Posts: 17,341
  • Joined: 17 Dec 2004
  • Loc: Highland Park, CA

Posted 03 December 2022 - 05:46 PM

That pic is of the mount after I'd attached the legs and before I tipped it out of the van to the ground.

 

 

Attached Thumbnails

  • Image (5).jpeg

  • Chris Cook, steve t, Bomber Bob and 1 other like this

#5 tim53

tim53

    James Webb Space Telescope

  • *****
  • topic starter
  • Posts: 17,341
  • Joined: 17 Dec 2004
  • Loc: Highland Park, CA

Posted 03 December 2022 - 05:47 PM

And that shows the rusty steel pier with round holes for mounting the legs.


  • steve t likes this

#6 tim53

tim53

    James Webb Space Telescope

  • *****
  • topic starter
  • Posts: 17,341
  • Joined: 17 Dec 2004
  • Loc: Highland Park, CA

Posted 03 December 2022 - 05:48 PM

The legs:

 

 

Attached Thumbnails

  • Image (4).jpeg

  • steve t, Bomber Bob, zakry3323 and 1 other like this

#7 rob1986

rob1986

    Gemini

  • -----
  • Posts: 3,498
  • Joined: 15 Dec 2020

Posted 03 December 2022 - 05:57 PM

wow. how are the optics and their associated mechanics?



#8 tim53

tim53

    James Webb Space Telescope

  • *****
  • topic starter
  • Posts: 17,341
  • Joined: 17 Dec 2004
  • Loc: Highland Park, CA

Posted 03 December 2022 - 06:07 PM

The primary is a bit translucent, but shiny. I need to pull the mirror and look for specs. 


  • bob midiri likes this

#9 Bomber Bob

Bomber Bob

    ISS

  • *****
  • Posts: 24,579
  • Joined: 09 Jul 2013
  • Loc: The Swamp, LA (Lower Alabama)

Posted 03 December 2022 - 06:33 PM

Sweet!  Congrats!!



#10 tim53

tim53

    James Webb Space Telescope

  • *****
  • topic starter
  • Posts: 17,341
  • Joined: 17 Dec 2004
  • Loc: Highland Park, CA

Posted 03 December 2022 - 06:43 PM

Man I hate the latest update to iOS. It used to be easy to email photos to myself so I could reduce their sizes.  Ow I have a couple hoops to jump through. 
 

the mirror could use a recoat, but it’s not bad at all

 

there was actual mud on the mirror, but I washed it off. It was apparently purchased from telescopics as a kit. It’s a cast Pyrex blank with the step around the rim back side. Not a raised rim like my later Pyrex mirrors. There were a couple names engraved in the back, and f/7. But the names are scratched out. One is either Douglass or Donald Allen. The other is harder to read, but looks like Daniel burrell or something similar. 
 

around the edge is 

“Refigured by Cave Optical Co” in script lettering, and

R672789 f/6.8 68 1/4” F.L. July 25, 1967

 

tim


  • tony_spina, Chris Cook, icomet and 2 others like this

#11 cavedweller

cavedweller

    Apollo

  • *****
  • Posts: 1,434
  • Joined: 06 Jun 2016
  • Loc: Ridgecrest, CA

Posted 03 December 2022 - 07:52 PM

That is about the condition of a 12.5" F/5 Cave I brought home a year ago. I will be watching your restoration to give me an idea of what is ahead of me.


  • tim53 likes this

#12 icomet

icomet

    Apollo

  • *****
  • Posts: 1,010
  • Joined: 09 Apr 2010
  • Loc: Montana

Posted 04 December 2022 - 11:34 AM

I like what the previous owner did with the rust and corrosion highlights.  grin.gif 

 

Clear Skies. 


  • tim53 likes this

#13 icomet

icomet

    Apollo

  • *****
  • Posts: 1,010
  • Joined: 09 Apr 2010
  • Loc: Montana

Posted 04 December 2022 - 01:53 PM

I'll have you know, Tim's not saying anything about the other scope he was considering at the same time 

with the Cave 10".

 

Here, I'll let you in on it.

 

Clear Skies. 

Attached Thumbnails

  • easy chair scope.jpg

Edited by icomet, 04 December 2022 - 01:54 PM.

  • tim53, Jeff B, steve t and 5 others like this

#14 Chris Cook

Chris Cook

    Messenger

  • *****
  • Posts: 426
  • Joined: 25 Jan 2007
  • Loc: California

Posted 04 December 2022 - 01:58 PM

Great find!!

Enjoying the restoration.



#15 Kasmos

Kasmos

    Cosmos

  • *****
  • Posts: 7,514
  • Joined: 19 Aug 2015
  • Loc: So Cal

Posted 04 December 2022 - 03:48 PM

Tim, when you commented on this scope in the ads thread you said something like, "too many projects and no room in the shop".

 

What made you Cave and where will it fall on the project list? wink.png


  • tim53, steve t and Bomber Bob like this

#16 tim53

tim53

    James Webb Space Telescope

  • *****
  • topic starter
  • Posts: 17,341
  • Joined: 17 Dec 2004
  • Loc: Highland Park, CA

Posted 04 December 2022 - 05:41 PM

I caved because it didn't look like anybody else was going to save it.  And judging from the seller's other "projects", I'm not sure it wouldn't have ended up in a dumpster.  I parked my van over a mud puddle so we wouldn't have to step in it to load the scope.

 

It's good it's not an f/8, because my shop ceiling is maybe 7 ft, probably. more like 6' 8", so I can stand the OTA up and it has about a square ft footprint.  The mount's currently outside until I can get it apart.

 

-Tim.


  • steve t, Bomber Bob and Kasmos like this

#17 CHASLX200

CHASLX200

    ISS

  • *****
  • Posts: 43,954
  • Joined: 29 Sep 2007
  • Loc: Tampa area Florida

Posted 04 December 2022 - 07:18 PM

I caved because it didn't look like anybody else was going to save it.  And judging from the seller's other "projects", I'm not sure it wouldn't have ended up in a dumpster.  I parked my van over a mud puddle so we wouldn't have to step in it to load the scope.

 

It's good it's not an f/8, because my shop ceiling is maybe 7 ft, probably. more like 6' 8", so I can stand the OTA up and it has about a square ft footprint.  The mount's currently outside until I can get it apart.

 

-Tim.

Mount looks to be just like the one i had on a 1965 made 10" F/8 Cave.


  • steve t likes this

#18 dgreyson

dgreyson

    Apollo

  • *****
  • Posts: 1,011
  • Joined: 06 Nov 2012
  • Loc: South Carolina

Posted 05 December 2022 - 11:53 AM

Nice find Tim. Synchronous motors usually only fail because the grease has dried out into solid wax and binds the gear train. If you're going to toss the motor anyway, try re hydrating the grease first. I haven't found an antique clock motor I couldn't get working again. Get a fine small drill bit and carefully perforate the gear housing. Be careful not to get metal shavings inside. Then inject a generous amount of penetrating oil and shake it up awhile, then shake out the dirty oil from the housing. Usually takes a few cycles to get it clean. I will be surprised if your motor doesn't work again. Seal the hole with silicone caulk etc and if it doesn't restore it to operation you haven't lost anything.
  • tim53, clamchip, steve t and 2 others like this

#19 tim53

tim53

    James Webb Space Telescope

  • *****
  • topic starter
  • Posts: 17,341
  • Joined: 17 Dec 2004
  • Loc: Highland Park, CA

Posted 05 December 2022 - 12:56 PM

Nice find Tim. Synchronous motors usually only fail because the grease has dried out into solid wax and binds the gear train. If you're going to toss the motor anyway, try re hydrating the grease first. I haven't found an antique clock motor I couldn't get working again. Get a fine small drill bit and carefully perforate the gear housing. Be careful not to get metal shavings inside. Then inject a generous amount of penetrating oil and shake it up awhile, then shake out the dirty oil from the housing. Usually takes a few cycles to get it clean. I will be surprised if your motor doesn't work again. Seal the hole with silicone caulk etc and if it doesn't restore it to operation you haven't lost anything.

I would try to revive it, but the cover is missing  and likely has been for years, so the internals are badly weathered.  I'll try to take a pic of it at some point.



#20 NinePlanets

NinePlanets

    Mercury-Atlas

  • *****
  • Posts: 2,891
  • Joined: 12 Sep 2018
  • Loc: High and Dry

Posted 05 December 2022 - 01:03 PM

I wonder if CorrosionX would work on a badly corroded motor. Winding insulation? Don't know. Never tried it, but it sure works wonders on iron oxide.



#21 tim53

tim53

    James Webb Space Telescope

  • *****
  • topic starter
  • Posts: 17,341
  • Joined: 17 Dec 2004
  • Loc: Highland Park, CA

Posted 05 December 2022 - 01:05 PM

I realized I have a picture that I could sharpen:  

Attached Thumbnails

  • Hurst.jpg

  • steve t, Geo31, Bomber Bob and 1 other like this

#22 apfever

apfever

    Cosmos

  • *****
  • Posts: 8,583
  • Joined: 13 May 2008

Posted 05 December 2022 - 02:20 PM

It looks nice to me. I'd take the motor apart as far as I could mechanically and still get it back together. Then I'd drop anything with rust into some evaporust type dissolver. You will probably be getting a gallon or two of that type dissolver for the resto anyway. The motor reduction box can get two small holes, on opposite sides, just big enough for the smallest straws on spray lube type cans. Much smaller holes if you use a hypodermic. Then you can flush a blast of whatever through the gear box - each way. Maybe fill the gearbox with solvent and quickly flip it to set it in a shallow pan of solvent to soak. That way the solvent won't run out the top or into any motor parts soldered on or riveted.  Maybe just throw that ugly rusted butt ugly mass of motor in the garbage. 


Edited by apfever, 05 December 2022 - 02:41 PM.

  • tim53, steve t and dgreyson like this

#23 apfever

apfever

    Cosmos

  • *****
  • Posts: 8,583
  • Joined: 13 May 2008

Posted 05 December 2022 - 02:41 PM

Ung. Caution. I just checked the DEC drive on my 8" Cave that is very similar. It is Hurst motor and 360 brass gear in a clutch hub. Your motor attachment looks the same for what I can see. If yours is the same as mine then this is all bass ackwards. Mine has the motor attached to the saddle and the gear clutch plates are attached to the DEC housing. This makes the clutch stay still while the motor tracks around the gear along with the DEC shaft and saddle. My motor does clear the RA housing but it would eventually wind up the wires if not careful. This could make a difference on how you check things for movement. 

 

I looked at some other larger GEM mounts with 360 clutch DEC drives and they were all 'normal' with the clutch on the shaft and the motor on a backing plate that attached to the DEC housing. 


Edited by apfever, 05 December 2022 - 02:42 PM.

  • tim53 likes this

#24 Compressorguy

Compressorguy

    Vanguard

  • *****
  • Posts: 2,446
  • Joined: 14 Mar 2009
  • Loc: Clayton, NC

Posted 05 December 2022 - 03:54 PM

Man I hate the latest update to iOS. It used to be easy to email photos to myself so I could reduce their sizes.  Ow I have a couple hoops to jump through. 
 

tim

By far the best and easiest photo resizing app I’ve used. Maybe it could help someone. Plus it allows deletion of the large original so you don’t end up with a bunch of duplicates.

 

58226404-47B8-43E6-8D96-CEA5ACA1277A.jpeg

 

 

BTW Nice score on the Cave. It would have been very difficult to let that pass if it were close to me and would love to have another someday. Especially a 10” f6, f7 or f8


  • tim53 likes this

#25 tim53

tim53

    James Webb Space Telescope

  • *****
  • topic starter
  • Posts: 17,341
  • Joined: 17 Dec 2004
  • Loc: Highland Park, CA

Posted 06 December 2022 - 12:48 PM

This morning I remembered to squirt a bunch of penetrating oil on all the rusty bolts and counterweight/shaft interfaces on the mount.  I'd take a picture, but it's rather messy looking with all them runs down the pier and stuff.  But if I can free things up enough to be able to use the mount to hold the tube off the ground tomorrow night, I might try this puppy out on the Mars occultation.  Of course, Mars needs to also be visible, and the forecast so far is for partly cloudy skies.  Same as now, where maybe 30% of the sky isn't cloudy.

 

-Tim.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics