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Monolux 4366

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#26 ftwskies

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Posted 21 January 2017 - 01:54 PM

By the way, a question...

 

The scope has a small screw on the tube ventral centerline near the focuser.  It's different from the three screws that attach the focuser.  It's not in plane with the three focuser screws, it's a flat-head standard vs. a round head Phillips, and it's slightly recessed.  Before I start disassembling the OTA and get myself into trouble, can anyone tell me what this little screw's job is and what it mates to inside the tube?  It's the screw outlined in red below:

 

gallery_240021_6729_41256.jpg



#27 deSitter

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Posted 21 January 2017 - 04:44 PM

Remove the focuser and look! Maybe it's a balance weight.

 

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#28 deSitter

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Posted 21 January 2017 - 04:49 PM

Hey I found you an achromat for your finder, D=25.4 F=100 - it's item AC254-100-Ad on this page..

 

https://www.thorlabs...ectgroup_id=120

 

-drl


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#29 Stargoat

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Posted 21 January 2017 - 05:39 PM

By the way, a question...

 

The scope has a small screw on the tube ventral centerline near the focuser.  It's different from the three screws that attach the focuser.  It's not in plane with the three focuser screws, it's a flat-head standard vs. a round head Phillips, and it's slightly recessed.  Before I start disassembling the OTA and get myself into trouble, can anyone tell me what this little screw's job is and what it mates to inside the tube?  It's the screw outlined in red below:

 

gallery_240021_6729_41256.jpg

Indeed it is an internal balance weight just as deSitter suggested.

 

IIRC, you will find that the two screws for the finder bracket will pass thru clearance holes in the tube and actually thread into the balance weight. Thus the recessed flat head screw orientates the weight to line up for the finder bracket thumb screws. Some of the models may have three of these flat head screws.

 

Here is a Tasco 9TE 175X from 1962/63 with one flat head screw for reference.

Attached Thumbnails

  • OTA Bottom View of Focuser Pinon and Offset Flat Hd Screw.JPG

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#30 ftwskies

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Posted 21 January 2017 - 07:52 PM

That explains it!  I was seeing a second layer beneath the tube around the finder bracket holes, but figured it was just a nutplate to support the (rather hefty) finder bracket mounting screws in the thin tube wall.  

 

Thanks!  I was afraid to remove the finder without knowing what this screw was for first. I've had enough experience with disassembling stuff blind and sometimes there's one screw holding something complex together that can't easily be reassembled, so...



#31 ftwskies

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Posted 21 January 2017 - 08:03 PM

Hey I found you an achromat for your finder, D=25.4 F=100 - it's item AC254-100-Ad on this page..

 

https://www.thorlabs...ectgroup_id=120

 

-drl

Hey, thanks for looking out for me!  That's actually been kind of an osyssey all it's own.  The original finder objective appears to have been an achromat, but the flint was missing when I got the scope.  I bought a cheap 5x24 finder, but couldn't harvest the objective from it because the assembly was glued together.  Then on SurplusShed I found a singlet double convex lens with a slightly shorter FL (~90mm) but the right diameter.  That's what's in there now, but man is the color horrible!  So it's kinda just a placeholder for now.  (It's still better than the original crown because at least it has the right FL; the original crown is more like 43mm without its flint.)  Recently I found an achromat at SurplusShed that has a 100mm FL, but the diameter is more like 26mm - just slightly too big to fit into the slot in the finder front end.  The other night I took it out and just held it up over the end of the finder tube, and man is it nice!  So my plan is to use it, but first I need to carefully grind about 0.5mm off the circumference so it fits.  I've done that kind of thing before when making my own color filters.  My drum sander should get the job done nicely.  I just haven't gotten around to that step yet. 



#32 ftwskies

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Posted 26 January 2017 - 01:45 PM

The drum sander in my drill press is working well to slowly remove ~1mm diameter from the new achromat finder objective I bought from SurpluShed. (It's a 26mm doublet and the finder tube wants a 24-25mm lens.)  I'm looking forward to finishing that admittedly risky process with the glass fully intact.  (I'm pretty sure the Towa 5x24 finder originally came with a doublet, but when i got the scope it only had an ~f/2 crown lens and no flint.)  Preliminary looks show this replacement to give nice crisp views.

 

Last night I spent a little time after church prepping the accessories for refinishing.  In addition to the finder, the scope came to me with a Big Bag O' PartsTM that (with a little trial and error) assembled into the original Monolux-branded 2X Barlow, 1.5X image erecting tube and prism diagonal.  After carefully removing the beautiful Monolux tags (which thankfully came off easily with no damage), I completely disassembled each unit into its constituent parts, methodically noting the orientation of lenses, etc. on note cards so I could take the photos below for later reference.  Tubes, cells, etc. were then set aside to get prepped for new paint, while the "guts" of each unit were carefully sorted into ziploc baggies along with the note cards for short-term storage.  I used tiny squares of post-it note to label the "eye-side" of each little lens, then wrapped each in Kimwipes, then in scotch tape, and then labelled each with their position within the assembly (finder eyepiece upper, erecting tube lower, etc.)

 

I was very impressed with the construction of the diagonal; the body is that heavy-duty vintage black plastic (bakelite?) with brass helicoils for the lid screws; the lid was painted flat black on the back, and look at that spring!  Care and attention was clearly paid to the design of it -- as opposed to modern prisms, which usually just have a bent strip of metal pushing against a piece of black construction paper under the prism.  I discovered a circle-T mark lightly molded into one side of the diagonal body, so I'm guessing the piece was either made by Tani or Towa -- any idea which is more likely?

 

On the downside, I'm really not impressed by the poor quality of castings on the knurled lens cells in the Barlow and erecting tubes.  (See post #25 above.)  They're fully functional, but there are big voids in some of the threads, and some of the chrome nose/tail-pieces thread loosely into/onto the mating tubes.  (This speaks to an earlier, rather than later age for the scope, IMO.)  In the case of the Barlow nosepiece it can even be pulled right off the lens cell with a gentle tug.  Several of the nose/tail-pieces are dull silver instead of bright chrome, so I'm wondering if the parts used to fit tighter before the chrome came off...  I was thinking about simply polishing these dull pieces to a nice soft shine, but if re-chroming is the only way to tighten up the threads then maybe I'll see if a local shop can do that for me.  Anyone have experience with re-chroming small aluminum parts?

 

gallery_240021_6729_35220.jpg

 

gallery_240021_6729_67942.jpg

 

gallery_240021_6729_235.jpg

 

gallery_240021_6729_80983.jpg


Edited by ftwskies, 26 January 2017 - 01:49 PM.

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#33 ftwskies

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Posted 31 January 2017 - 10:27 PM

As Miss Kaylee Frye would say, "Ooh, shiny!"  :cool:

 

The accessories are stripped and ready for prime and paint.  Check out those solid castings -- those altitude bearings could be belt buckles!  And that finder holder!  :shocked:

 

I have something special in mind for the paint.  Anyone wanna wager what I've picked out?  Hint:  It won't be traditional black/white... ;) 

 

I'll do the finder first to see how I like the new scheme before pressing ahead with the rest of the kit.  Once these accessories are complete, I'll turn my attention to the OTA, then the tripod and mount.  After that, I'll build a custom wooden case, and decide on a set of eyepieces to pack in with it.

 

gallery_240021_6729_59385.jpg

 

gallery_240021_6729_177479.jpg


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#34 ftwskies

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Posted 01 March 2017 - 10:48 PM

Okay... Here's the first big reveal...  I still need to swing by Lowe's and pick up some contact cement so I can glue on the Monolux labels, but in the meantime, check out Molly's new duds!  This is the color scheme I'm using for the whole kit; in case it's hard to tell, it's an antique white and a medium army green.  The white is a Chrysler color, Duplicolor BFM0041 Wimbledon White.  The green is Testor's #1913 Medium Green, which is equivalent to Fed Std #34102.

 

gallery_240021_6729_77742.jpg

 

I tried to make the antique white show up better by setting the finder on a bright white sheet of paper under a "daylight" colored LED bulb, but it didn't turn out as well as I hoped.  I had to fiddle with the brightness and contrast so the green showed up halfway natural, but that made the white look washed out:

 

gallery_240021_6729_31339.jpg

 

Trust me, it's antique white.  lol.gif  What I really need to do is get the kit out under real daylight and snap some pics.  I'm really in love with this color scheme.  It was inspired by the Swift not-black-and-white scheme, and my son's WW2 army footlocker (inherited from my wife's grandfather).  I didn't want to do straight black and bright white, because I felt like that would be cliche.  I wanted something that spoke "old" or "vintage" to me, which these colors do.  I'm happy with it and can't wait to get the whole OTA done in the same colors.  The green is going on the mount hardware, too, when I refinish that.  It's a nice shade IMO -- not really faded or brownish olive like a modern military camo green might be, but not bright Kelly green either.  Just yellowy enough to work with the antique white and look aged, I guess.  shrug.gif

 

So...  What do you think?  waytogo.gif  or thumbsdown3.gif ?  Or maybe just fingertap.giflol.gif

 

EDIT:  Forgot to mention, the green only comes in flat.  I've been putting one coat of Testor's gloss lacquer over it, though, and it turns out the perfect satin sheen.


Edited by ftwskies, 01 March 2017 - 10:49 PM.

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#35 TOM KIEHL

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Posted 01 March 2017 - 11:20 PM

waytogo.gifis what I think ...... And if you are having fun doing it ....waytogo.gifwaytogo.gif


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#36 Vesper818

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Posted 01 March 2017 - 11:22 PM

Just in time for St. Patrick's day!
Unusual, but handsome classic color scheme. Gotta love these great fixer uppers that you can add your own touch to.
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#37 ftwskies

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Posted 02 March 2017 - 10:12 AM

waytogo.gifis what I think ...... And if you are having fun doing it ....waytogo.gifwaytogo.gif

I'm havin' a blast, Tom.  If this was any more fun, it'd probably be illegal.  lol.gif


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#38 Terra Nova

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Posted 02 March 2017 - 10:17 AM

Beautiful! That li'l scope will be a looker!


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#39 paulymo

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Posted 02 March 2017 - 03:50 PM

Definite waytogo.gif



#40 ftwskies

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Posted 02 March 2017 - 04:48 PM

Thanks, everybody.  I can't wait to see the whole kit once I get it refinished.  I think it'll look classy.


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#41 ftwskies

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Posted 04 March 2017 - 07:10 PM

Not a huge advance, I know, but I wanted to post another picture of Molly's accessories now that I got the labels glued back on:

 

gallery_240021_6729_128459.jpg

 

So I'm finally officially ready to move onto the OTA!  waytogo.gif


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#42 ftwskies

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Posted 06 March 2017 - 01:35 PM

Disassembled the OTA for cleaning and refinishing on Friday evening.  I'll post tear-down pics tonight if I find some time.


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#43 ftwskies

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Posted 07 March 2017 - 11:47 PM

Last night I didn't get home until 8pm.  I was so knackered by that time that I sat down in my recliner and fell fast asleep before I could get my pictures uploaded.  :lol:

 

So here, without further ado, are my teardown pics from Molly's OTA.  I'm posting these not only to document progress on the refurb, but for future reference in case anyone is ever curious about how this model is put together.

 

First, here's the patient, prepped and ready for what's next:

gallery_240021_6729_168076.jpg

 

Here's the teardown of the focuser.... 

 

The focuser has a short drawtube.  I'm wondering whether this will be a problem when it comes to finding eyepieces for it?

 

gallery_240021_6729_61253.jpg

 

Dat beeyootiful label, doh...  flowerred.gifwub.png

 

gallery_240021_6729_119180.jpg

 

Here's a view of the assembled focus mechanism...

 

gallery_240021_6729_122156.jpg

 

...And here it is with the lid off...

gallery_240021_6729_90437.jpg

 

...And fully disassembled.  The three leaf springs stack to provide sufficient thrust on the pinion to keep it pushed up into the rack.  The ends of the springs load into the little steps on the inside of the gear block.

 

gallery_240021_6729_89931.jpg

 

I even removed the rack from the drawtube so I can clean it and polish the drawtube.

 

gallery_240021_6729_77305.jpg

 

The painted parts are ready to be degreased, stripped and refinished in lovely Testor's Medium Green...

 

gallery_240021_6729_106426.jpg


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#44 ftwskies

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Posted 07 March 2017 - 11:47 PM

Here's a shot looking into the rear of the open tube.  That (rather slovenly drilled) ring is the one you guys told me about earlier when I asked about that small ventral screw.  Stephen mentioned it was a counterweight.  I'm calling it a bulkhead and thinking it serves to stiffen the tube where the finder is attached.  With that small screw removed, it slips right out.  I plan to clean up the sloppy drill job before I reassemble.  Why bother?  Because I can...  (That's just how we roll... :cool: )

 

gallery_240021_6729_197302.jpg

 

And here's a view down the front of the open tube.  The tube itself only has one baffle, about 2/3 of the way back from the objective.  The second baffle you see is press-fit into the front of the focuser drawtube.

 

gallery_240021_6729_89088.jpg

 

Here's the objective lens cell.  Standard Towa fare.  :fingertap:

 

gallery_240021_6729_172332.jpg

 

And here's a couple of shots that show the dings I need to fix in the dew shield before I can repaint it.  I'll strip it first so I can see them more clearly to fix them.

 

gallery_240021_6729_153232.jpg

 

gallery_240021_6729_45914.jpg

 

 

I have to set this one aside for a week or two because of something else I've got going, but when I come back to it it'll be time to take the tube, cell, dew shield, focuser body and focuser block out to the shop for degreasing, stripping and prime/paint!  :waytogo: Next stop:  SHINY TOWN!  :lol:


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#45 ftwskies

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Posted 20 March 2017 - 10:10 PM

See?  SHINY!!  Ooooooooohh..... blush.gif

 

gallery_240021_6729_98695.jpg

 

The one item conspicuously missing from this picture is the tube itself.  The white finish is being extremely stubborn; my spray-on aircraft remover is hardly making a dent in it for some reason.  After practically hosing the thing down, the finish is getting goosebumps and getting a little soft, but I finally had to leave it for the night and plan to come back to it later in the week.  I may try some light sanding just to break up the gloss a little so the stripper can penetrate better.  If that doesn't work, I'll try a different chemical - maybe some citrus stuff or something.  confused1.gif

 

The pic below highlights the two minor dings in the dew shield that I need to smooth out before I prime/paint.  If you look really closely, just above the two dings there's a slight dent in the rim as well.  Chris' thread on removing dents and dings is timely for me!  waytogo.gif

 

gallery_240021_6729_64678.jpg

 

 

 

D'Oh!  foreheadslap.gif   Just realized that I forgot to strip the focuser gearbox...    Oh, well.  It's small, I'll get it later this week...


Edited by ftwskies, 20 March 2017 - 10:11 PM.

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#46 ftwskies

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Posted 21 March 2017 - 09:50 PM

Stripped the focuser block tonight; it came clean easily using the methyl chloride aircraft stripper. Tried the stripper on the tube again though, and again it hardly made a dent in the finish. I'm suspicious that the paint may be lead based because of how the stripper makes it waxy and gummy but doesn't really loosen it. So I cleaned it off and tried citrus stripper instead. The paint didn't bubble or wrinkle but after a few minutes I was able to use the side edge of a metal scraper to gently rub off the hard glossy white top coat, exposing a thinner, duller powdery white undercoat (primer?). I left most of this dull undercoat intact to make sure I wasn't scratching or gouging the tube. I'm going to try the methyl chloride stripper on the undercoat later this week. Hopefully by this weekend I'll be ready for primer on all the parts.

#47 TOM KIEHL

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Posted 21 March 2017 - 10:25 PM

" my spray-on aircraft remover is hardly making a dent in it for some reason "  I had the same problem with the spray.  Tried it once , never again . The brush on worked the best for me . The secret with the brush on is , brush it on in one direction .



#48 ftwskies

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Posted 21 March 2017 - 10:32 PM

" my spray-on aircraft remover is hardly making a dent in it for some reason " I had the same problem with the spray. Tried it once , never again . The brush on worked the best for me . The secret with the brush on is , brush it on in one direction .


Yeah, I really don't get it, Tom: When I used it on my late 70s Milben the paint practically fell off after five minutes. On this older (early 60s) Monolux it's been hit or miss. Some of the parts have shed like a snake, others needed two or three passes to get 100% clean. But this tube has been bulletproof somehow. I just hope the stuff works better now that I got the hard glossy layer off.
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#49 ftwskies

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Posted 26 March 2017 - 09:25 PM

Ready for prime and paint!

 

gallery_240021_6729_174633.jpg


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#50 ftwskies

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Posted 27 March 2017 - 05:14 PM

For posterity (and my own jumbled memory), here's a link to the only other Monolux 4366 owner I've ever been able to find, after scouring the internet for months.  Via link sleuthing the author is apparently a sci-fi writer named Larry D. Smith, but I haven't been able to track down any contact (email) for him.  The page seems a little bit dated; nevertheless I'd love to find a way to contact him and chat with him about his telescope and maybe compare notes.  It looks like my unit, as received, was more complete than his.  He didn't try to restore his, just to make it work for him.  I did note with interest that he found astigmatism in his objective and was able to reduce or eliminate it by rotating the relative crown and flint orientations.  (I hope I won't have to do that with mine to get a good image.  I had believed that small, mass-produced achromats were relatively impervious to rotational misalignment.)

 

http://www.astronomy...ew_monolux.html


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