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

The timeless "Another new post about a Criterion RV-6" post

  • Please log in to reply
9 replies to this topic

#1 oasmith

oasmith

    Lift Off

  • -----
  • topic starter
  • Posts: 20
  • Joined: 02 Aug 2017

Posted 28 March 2021 - 02:08 PM

Currently taking apart the axles and motor to put on new grease and try to tighten up the slop. Now, the dreaded cork ring for the clutch. Anyone know where I can get a replacement? What about lightly scarring the ring's surface with a wire brush to give it the friction it'll need? I'm not trying to make this thing as good as new, just something to do on a rainy sunday. Thanks for any help!

#2 ccwemyss

ccwemyss

    Surveyor 1

  • *****
  • Posts: 1,544
  • Joined: 11 Aug 2016
  • Loc: Massachusetts

Posted 28 March 2021 - 02:48 PM

Cork gasket from an auto parts supply, cut with a razor blade.

 

Chip W. 


  • AstroKerr likes this

#3 Bonco2

Bonco2

    Viking 1

  • *****
  • Posts: 624
  • Joined: 01 Jun 2013

Posted 28 March 2021 - 03:30 PM

Cork sheets available in craft stores.

Bill


  • Terra Nova and AstroKerr like this

#4 1939Dodge

1939Dodge

    Vostok 1

  • *****
  • Posts: 104
  • Joined: 06 Jun 2015
  • Loc: Pa.

Posted 28 March 2021 - 03:38 PM

Don’t modify the discs. Just put in a cork. It can be cut with scissors.


  • Terra Nova and AstroKerr like this

#5 apfever

apfever

    Fly Me to the Moon

  • *****
  • Posts: 6,112
  • Joined: 13 May 2008
  • Loc: Colorado

Posted 28 March 2021 - 07:20 PM

The cork is very thin,  1/32" thick. You have to use thin cork or the brass gear won't be supported right on the clutch disc. Look at the disc 'face plate' where the gasket goes. That disc has a raised center area. The cork gasket goes part way up the raised center, and the gear goes around the remaining part of the raised center area.  A thick gasket will raise the brass gear completely above the center section and that won't work.

 

Don't scratch up anything on the clutch with sandpaper.


Edited by apfever, 28 March 2021 - 07:21 PM.

  • AstroKerr likes this

#6 oasmith

oasmith

    Lift Off

  • -----
  • topic starter
  • Posts: 20
  • Joined: 02 Aug 2017

Posted 02 April 2021 - 11:03 AM

Thanks all. I did find a cork sheet at the auto parts store, but it's 1/16, not 1/32. I put it in anyway, and the gear does engage. I'll have to test it out tonight or tomorrow tonight to see how well it tracks. 


  • jim kuhns and AstroKerr like this

#7 PiSigma

PiSigma

    Mercury-Atlas

  • *****
  • Posts: 2,569
  • Joined: 14 Oct 2009
  • Loc: Indianapolis

Posted 04 April 2021 - 11:30 AM

Neil is correct. The gasket needs to be 1/32". This thickness is used in woodwind musical instruments. I found it at musicmedic.com or try a local music shop if you still have one. You can use the clutch parts as patterns to cut the cork. More details in post #11 of my RV-6 thread:

 

https://www.cloudyni...ck-restoration/

 

https://www.musicmed...101-6mm-sheets/


Edited by PiSigma, 04 April 2021 - 11:31 AM.

  • GreyDay likes this

#8 oasmith

oasmith

    Lift Off

  • -----
  • topic starter
  • Posts: 20
  • Joined: 02 Aug 2017

Posted 04 April 2021 - 08:22 PM

Thanks Jon, your restoration is awesome, i wish i had seen it sooner. The 1/16th seems to be engaging the clutch, and all the plates fit snuggly together. It tracks about the same as it did before i took it apart, so at least i didn't make it worse. I did read about how you had a brass bushing that someone else did not have. When i removed the clutch plates, there was a worn down groove in the housing plate as though something had been there, but nothing fell off, and the top plate didn't have a matching groove. So, I did not have the brass bushing, but there might have been something there. 

 

Anyway, the main point of me taking it apart was to try to really lock in the tracking ability. I've been fiddling with some long exposures using my Pixel 4a phone, and I do end up with some small streaks after 30sec photos. But i guess i should ask you all, has anyone done long exposures with the RV-6? It'll tack fine enough for people taking turns looking at Jupiter, but long exposures really show the drift (like for M65 and M66, and Whirlpool). And it's not always in the same direction.  I was hoping a new cork ring would fix the issues. I've got it lined up with Polaris, and on fairly level ground.

 

One issue I'm having is figuring out the balancing. But, I also read in your post that for the old camera mount, it seems the intent was rotate the tube to keep the weight of the camera on the top side of the tube. Is this how it should always be done. Depending on where I'm looking, I have to add or remove little weights at the bottom of the tube to compensate. I also add weights to the main counterweight to compensate for all the weight I just added to the tube. 



#9 Bonco2

Bonco2

    Viking 1

  • *****
  • Posts: 624
  • Joined: 01 Jun 2013

Posted 05 April 2021 - 03:23 PM

Without slomo controls for RA and Dec, the drive is is less than ideal for long exposures. The telescope is perfectly capable of deep sky photography on a better mount. However the eyepiece focuser tho is not the best for AP.

Bill



#10 apfever

apfever

    Fly Me to the Moon

  • *****
  • Posts: 6,112
  • Joined: 13 May 2008
  • Loc: Colorado

Posted 05 April 2021 - 08:41 PM

Busting myth about the clutch gasket.

 

The brass ring gear is sandwiched between the two aluminum plates. Each plate has a raised center section (green arrows) that fits into the center of the ring gear. The left plate only has a 1/32" raised center section. The right plate has a 1/8" raised center section and this is the plate that takes the gasket. 

 

On the left side of the red circle are two side plates pressed together without the ring gear. The gap for the gear is the same as the thickness of the gear. Any gasket thickness from about 1/64" (milk jug) on up will separate the side plates enough for the system to work - as long as there is some raised center section remaining to engage the ring gear. All of the original cork I've measured have been 1/32" thick. The thin gaskets keep the distance between the plates minimal. 

 

There is an advantage to keeping the gasket thin so the plates stay close together. The larger the gap between the plates, the more strain is applied to the brass pins and tension screws holding the two plates in position. I don't think a 1/16" gasket is any problem so the OP's clutch should be in good shape. I wouldn't hesitate to use a 1/16" gasket if that was a big convenience.  I'd balk at going thicker as a pure gut feeling with 1/16" being double the original thickness. Even a hair thicker than 1/16" would probably never be noticed but each has to draw their own line. 

Attached Thumbnails

  • P1010022.JPG

  • Bonco2 and GreyDay like this


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