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Goto Kogaku 451 with Baekelite Saddle and Frozen Mount

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#1 Van Do9:3

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Posted 11 June 2020 - 09:36 PM

Hello All,

 

Hope everyone is healthy and well. I started this thread in the Finds Forum, post #8666. The Goto Kogaku 451 is in good condition overall but very dirty. Aluminum tube with Baekelite objective cell capped with chrome stainless steel dew lid, and rotating Baekelite focuser assembly. The mount is cast aluminum with Baekelite saddle. The mount is the first order of business in reconditioning this classic.

 

My search found a couple of 451 CN threads noting frozen mounts, and I believe this mount is also frozen. Normally, when the azimuth locking bolt is disengaged, the mount head can be  rotated freely, 360, for coarse adjustment. However, I can only rotate this mount head about 1/4”.
 

E82EFE0D-6639-43ED-BFF5-A6F8F40DE837.jpeg

 

When I lock the azimuth bolt, I can fully compress the azimuth piston with the fine adjustment knob but the mount head only rotates about an inch (apologies I did take degrees measurements).
 

D7FB7194-9F0E-4761-9194-B552042D5868.jpeg

A94D8C4B-67FB-43F3-B7BC-49273E79B22C.jpeg

 

When I back out the fine adjustment knob, the azimuth arm and compression piston freeze midway. 
 

E077878B-0222-4AD4-A0E5-2BF0BCA2F9FD.jpeg

 

0B217C1F-F225-45A3-A7BB-ECBB9920DC3C.jpeg

 

What are possible causes for the frozen mount? I removed the azimuth locking bolt and the grub retaining screw but was unsuccessful in disassembling the mount head. Do I also need to remove the compression piston and the azimuth arm?
 

Much appreciation in advance for your consideration and any advice and insights you would like to offer.
 

- My


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#2 CharlieB

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Posted 11 June 2020 - 10:02 PM

I don't have this particular mount, but I've run across the same problem on a few other mounts.  It could possible be that the azimuth locking bolt actually presses against a brass rod, which does the actual locking.  Try to unscrew the locking bolt all the way and peek inside the threaded hole.  If you see a piece of brass, it may be that this is stuck to the shaft that the azimuth rotates on.  You will then have to find a way to remove it.  I had to drill a hole in the brass and use a screw extractor, but other here may have a less drastic method.

 

Charlie


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#3 CharlieB

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Posted 11 June 2020 - 10:03 PM

You probably don't have to remove the compression assembly.


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#4 strdst

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Posted 12 June 2020 - 12:55 AM

My,

 

Does your tripod flange separate from the rest of the mount? I don't have a brass plug in mine it is just a screw that holds the azimuth from rotating 360 degrees around the tripod hub. Maybe I'm not sure what is stuck.

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  • P1010184 (1).jpg

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#5 Kasmos

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Posted 12 June 2020 - 01:32 AM

It seems there are perhaps 3 or 4 different versions of these mounts.

Van's has slow mo controls on the right and his hub looks different.

Plus in the finds thread he mentioned his saddle mount is Bakelite

Keith's controls are on the left and his hubs lugs look more angled like mine.

Mine has the controls on the left but with a tangent arm clamp.

Since it's different I can't be of help but thought you might like to see how it's differs.

Goto-Mount.jpg


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#6 Van Do9:3

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Posted 12 June 2020 - 07:14 AM

Charlie, Keith, and Chris,

 

Thank you for your replies. I removed the azimuth locking bolt and there’s not a brass rod. The tripod flange should separate like Keith’s Mount but it is stuck fast. I also looked at the bottom of the tripod flange and there doesn’t appear to be any retaining screws or pins. 

10C94726-F1D9-4990-AFA4-CD60BFD90CA6.jpeg

 

It is surprising to see so many subtle variants In these mounts. Goto must have had a plethora of design ideas and manufactured many of them. 
 

 


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#7 Bomber Bob

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Posted 12 June 2020 - 07:30 AM

In similar situations, I've removed the bolt, and soaked the joint(s) with Liquid Wrench or WD-40, using that thin straw extender to really get the oil in there.  Then, I turn the axis as far as I safely can, and blast it again & again, until it "gives" -- then I take it all apart, and strip out that pine-infused black tar grease, and re-grease with modern all-temp lube.

 

And... it could be that a prior owner took the mount apart, de-greased it, and you now have metal-on-metal (yep, I've seen that with some old scopes)...


Edited by Bomber Bob, 12 June 2020 - 07:31 AM.

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#8 Van Do9:3

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Posted 12 June 2020 - 08:42 AM

Thank you JW. I decided to apply some muscle before I tried your solution and I was able to break the grease bond. It’s surprising how the old grease degrades, coagulates, and bonds the parts. 

C4DA08E7-558E-4C62-9FD5-0383459E10CC.jpeg

 

012D45E9-E1D5-4D44-B53E-CE1C9B7BCBEC.jpeg

 

C6D5F90F-E342-4666-BCA3-1F3316EFA526.jpeg

 

I’ll report more after work but there’s some interesting details in what is a simple mount. What type/ brand of lubricant would you recommend?

 

 


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#9 Chuck Hards

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Posted 12 June 2020 - 09:01 AM

As the US cut-off Japan from their oilfields during the war, the Japanese turned to their native pine forests for raw materials including pine-based lubricants.  I'm sure the post-war export telescopes and binoculars were the recipients of much of that war-surplus "grease".  


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#10 Van Do9:3

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Posted 12 June 2020 - 09:19 AM

Chuck, 

 

That’s pretty cool to think grease can be derived from pine oil. Definitely makes a great glue with time and heat. 



#11 Bomber Bob

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Posted 12 June 2020 - 09:37 AM

Glad you could work it loose. See how that old grease clumps & hardens? Almost ALL my Classic Japan-made mounts had to be cleaned & re-greased.
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#12 ccwemyss

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Posted 12 June 2020 - 09:53 AM

I have found that odorless mineral spirits do a really good job of softening the old grease, and they are even thiner than WD40. 

 

Chip W. 


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#13 Chuck Hards

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Posted 12 June 2020 - 10:13 AM

Charcoal lighter fluid is my go-to solvent for old grease (pun intended).  It's inexpensive, the odor isn't offensive or particularly strong, and it works well.  Similar to kerosene but more readily available.  You can get it at the grocery store.


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#14 Van Do9:3

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Posted 12 June 2020 - 10:59 AM

I do have mineral spirits. I like the lighter fluid low fumes attribute. Will have to experiment to see which may work better. 
 

Do y’all have a brand/ type of lubricant you recommend? Here in NC, it gets cold but heat and humidity are the biggest concerns. 
 

Thank you.



#15 Kasmos

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Posted 12 June 2020 - 01:45 PM

IMO, you don't need anything fancy or modern. On mounts I usually just use what I have on hand like a simple automotive muti-purpose lithium grease. I like the old fashion amber colored stuff by Sta-Lube. It's not smelly and while it might harden someday, that will take another 30-40 years from now.

 

BTW, good to see you got it disassembled. waytogo.gif  


Edited by Kasmos, 12 June 2020 - 01:48 PM.

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#16 Terra Nova

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Posted 12 June 2020 - 04:55 PM

Charcoal lighter fluid is my go-to solvent for old grease (pun intended).  It's inexpensive, the odor isn't offensive or particularly strong, and it works well.  Similar to kerosene but more readily available.  You can get it at the grocery store.

It's prettymuch the same thing as naptha.


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#17 Van Do9:3

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Posted 16 June 2020 - 09:05 PM

Over the weekend I removed the nicely hardened pine resin lubricant from the mount with mineral spirits. In the process, the solvent soaking loosened the azimuth shaft and I was able to work it free from the hub flange. It’s a solid, heavy stainless steel shaft. This is what was stuck and contributed to gumming up the azimuth rotation. Thank you Keith for the photo of your disassembled mount. The shaft is threaded at the top but not directionally. It does screw into the mount head. The curious thing is that the shaft does not screw in completely. There is a disruption in the threading about mid way and it appears the treading was flattened, and a drill tap made to receive the grub screw. This looks strange to me. Shouldn’t the shaft screw in deeper and the grub screw then set into the notch of the shaft at the bottom of the threading?

 

2CD71FFB-EA96-4CD4-8AD9-6079FDA4FE51.jpeg

 

098F74A7-B444-4380-BC4D-A12E2E44FCD1.jpeg

 

16C9AE76-4D8C-44EE-B87A-5C26F452B12E.jpeg

 

E74BA53F-3F87-42D7-B599-C15E2BD80102.jpeg

 

Perhaps this was done because there’s nothing to gauge or stop the shaft from threading in too far and thus difficult to remove? Or Perhaps the threading makes a more solid/ homogenous connection with the mount head. In any case, it does put the shaft lower into the hub flange which means the center of gravity is lower and thus stabilizes the mount and tripod. 
 

5284EABB-1050-46CE-A2A3-B4E26CE251A6.jpeg

 

I decided I need some kind of gasket between the mount head and the hub flange so I cut out (please pardon the poor cutting skills) a gasket from an old milk jug. Hoping this smooths the azimuth rotation. 
 

446E91D1-9E44-4DE4-BA16-03D7890F2FAD.jpeg

 

For lubricating the fine adjustment controllers and the azimuth locking screw, I was deciding between Super Lube or the Nyoegl. I tested both between my fingers and the SuperLube was nice and light, and not sticky. The Nye Gel felt more viscous and sticky. The Nyogel may be better for r+p focusers because you want some stop stick-sion. The SuperLube washed off my fingers better than the Nyogel. 

25FCE1EB-572B-421E-B0A1-3795251C8BC7.jpeg

 


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#18 Van Do9:3

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Posted 30 June 2020 - 09:27 PM

Apologies it’s taken a while to post updates. I decided to do a little experiment with different lubes and greases to see if the summer sun and heat would affect their properties, mainly to see if any would be runny. 
 

The grey dollop is Aeroshell 64, the pink is Mobil 1 Synthetic, the white is SuperLube, and the yellow is Nyogel 7600. None were runny but the surprising one was the Nyogel 7600. It started out super clear, no color; however, it turned yellow after the sun bath. I guess UV changes its color. 
 

F97A6552-5058-47E2-90A1-A26933FD3E3F.jpeg  FF0DE3FC-45B2-48B7-99B7-5014BFC21746.jpeg

 

I chose to lubricate the mount seem shaft with Mobil 1 synthetic because it didn’t feel oily and left the finest film on my fingers. Second runner up would have been the SuperLube. Reassembled the mount, cleaned with mineral spirits, and polished with Blue Magic. Chris, Kasmos, is spot on about how it mystically makes any and all blemishes disappear. I originally thought there was rust on the tangent arms outrigger but it turned out to be schmutz. 

0D60215F-8C7B-4DD3-A6A2-F2959CE6DBE1.jpeg

3863482B-F54E-4868-AD99-B6F0B5D1A20F.jpeg  63E12CA3-EC01-4F5D-B1E5-5F1A7D78F7BB.jpeg

 

Next to be cleaned was the focuser assembly. It’s strange that it is secured to the OTA with one screw. It’s a little loose and you can feel the assembly shift a little when trying to rotate the focuser housing. The rack and pinion is very smooth so I decided to brush the old grease off of the rack and superficially clean the focuser tube and housing. The focuser extension tube With the compression fitting was not pulling out smoothly so I disassembled it and cleaned resulting in a firm but smooth extension motion. I love the matte finish of the focuser tube and how well it operates. The Bakelite focuser housing rotates but it takes some effort to do so. Need to get a pin spanner wrench to loosen the rotating focuser. 

 

Interesting to see how they stamped each assembly components with corresponding numbers. In the case of the focuser assembly, it was E38. But the housing is Baekelite so they scribed the number in lieu of stamping it. I had to research how to clean Bakelite and the best source is a British phone collectors site, https://www.britisht...om/bakelit1.htm of course car polishing compound was recommended, so Blue Magic to it. 

C8923B02-D9AE-42CE-8CD4-F1CF59F103A9.jpeg

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On to the objective. The objective cell is also Bakelite. When I removed the cell from the housing, a sliver of charcoal grey construction paper fell out. This is a shim to collimate the the cell. I found where the paper shim’s faint outline was on the cell flange. The oddest thing I discovered was a glob of dried hard glue resin affixing the brass retention ring to the Bakelite cell. Is this typical of Goto Kogaku 451 objective cells? The objective does move move/ rattle quite a bit in the cell. More so than any I have heard before. 

 

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#19 strdst

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Posted 29 July 2020 - 01:03 AM

Hello My,

 

Have you gotten your Goto out under a clear night sky yet? 


Edited by strdst, 29 July 2020 - 01:04 AM.


#20 Van Do9:3

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Posted 29 July 2020 - 09:10 AM

Keith,

 

I did. I haven’t had a chance to enjoy the 451 until a couple nights ago due to deadlines and the summer evening rains. Southeastern rainforest.  
 

About a month ago, I took the 451 out for a quick first light with the uncleared lens. Popped in a 20mm ep from the Mayflower and focused on Algieba. The double jumped into focus. Beautiful bright and clear. Got me excited to clean the lenses and get it to its optimum condition. 
 

I cleaned the objective of the funk and fungus, cleaned the prisms, and the 20/10mm and 6mm EPs, and got everything in proper working order last Friday. Jupiter’s belts were clear and prominent, no fuzziness. I haven’t tried viewing with my glasses so I might be missing more detail. Aging sucks. Saturn was brighter than I have observed in my other classics. First time I have seen Saturn’s moons, although dim but distinct. 
 

Arcturus and Spica are beautiful. Distinct airy discs, although not complete circles on the outer discs. Need more observing time and possible adjustments of the objective. No CA on bright objects, even on first quarter moon  I usually see a tinge of blue at the moon’s edge but not with the 451. 
 

i want to file more observation time but the 451 optics are superb. This is my favorite 60mm classic so far. It’s design is elegant, pure and simple, the mount, focus, and mechanics are smooth, and the complete set up is an easy one arm lift. 

851B8423-70F3-40B9-8968-DD47C22C506B.jpeg

 

I’ll post more on the cleaning and improvements, and viewing. I can attest that the Goto Kogaku 451 is one fantastic classic telescope.

 

- My. 


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#21 strdst

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Posted 30 July 2020 - 02:32 AM

I'm happy to know you are making progress and have gotten the first light experience with it! The 451 is one of the finest  telescopes in my ridiculously extensive collection of classic 60s.


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#22 Van Do9:3

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Posted 30 July 2020 - 12:05 PM

Thank you Keith. I am very much enjoying the 451. For a student vision telescope, it kicks! Perhaps an appropriate analogy is the VW Beetle? Made for the populace, simple design, just the essential well made parts, go anywhere, and can be maintained with a screwdriver. 
 

- My




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