Carol L
   
Reged: 07/05/04
Loc: Tomahawk, WI 45N//89W
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So frustrated i could just cry....
#5014849 - 01/13/12 01:46 AM
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A few days ago i received the Sky Commander DSCs and finally got around to installing them on the 16LB (very easy installation). When the scope was put back together, the azimuth was suddenly extremely difficult to move. I thought the pivot hardware might be too tight, but loosening it didn't help. In fact, no amount of re-adjusting the pivot hardware helped, so i got curious and put the original hardware back on the scope.
The azimuth was still extremely difficult to move... why would it suddenly do this?
A bit of background info: The scope was purchased in July 2010 and still has the original rocker box and groundboard. They're nearly pristeen, because the scope is kept on a wheelybar and has never touched the ground. Instead of formica and teflon for the azimuth, there's a big roller bearing sandwiched between two metal plates. Since day one, i could always hear the rollerbearings when i moved the scope left/right, but now i can't hear them at all. Just a rubbing sound caused by the groundboard's three small (teflon?) pads rubbing the bottom of the groundboard.
This past summer was unusually humid for a number of weeks, but even with all of moisture in the air, the scope performed the same as it always had... no warping of the boards or drag in the azimuth. The scope's kept in the shed, but the weather turned nasty so we brought the rockerbox and LTA inside so i could install the DSCs in comfort. They sat in the house for over a day before i started, and the humidity inside is usually about 45% - 50%... drier than the outside air.
Logically, it seems as though the groundboard and/or baseboard might have 'bowed' just a bit when i took the original pivot hardware out. This would explain why it acts the same way no matter which hardware is used. It would also explain why i can't hear the roller bearings anymore, but i can suddenly hear the outer edge pads rubbing on the bottom of the baseboard. Make sense? If the difference in humidity caused something to 'bow', might it 'un-bow' when the scope is placed back into the shed? I'd hate to have to replace the rockerbox and groundboard just because i wanted DSCs. If anyone has thoughts on this problem, i'd sure appreciate hearing from you. 
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Joe Bergeron
Vendor - Space Art
Reged: 11/10/03
Loc: Upstate NY
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Re: So frustrated i could just cry....
[Re: Carol L]
#5014880 - 01/13/12 03:05 AM
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When's the last time you observed normal motion in your mount? Was it working normally just before you installed the DSC hardware?
Try resting a straight edge on the ground board and the rocker board. That should make it easy to see any warping.
Maybe the roller bearing has rusted or been fouled by some contamination.
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bherv
Pooh-Bah
   
Reged: 03/10/06
Loc: WMass
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Re: So frustrated i could just cry....
[Re: Carol L]
#5014979 - 01/13/12 07:42 AM
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I would take the roller bearings out and check to see that they are all moving freely. Clean them with alcohol, let them dry and spray them with some silicon lubricant. Clean the plates also. Before putting scope back together, put the bearings between the plates to see if they move freely. Barry
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dan777
professor emeritus
   
Reged: 11/16/07
Loc: Indiana
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Re: So frustrated i could just cry....
[Re: Carol L]
#5015018 - 01/13/12 08:26 AM
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If the difference in humidity caused something to 'bow', might it 'un-bow' when the scope is placed back into the shed?
Unfortunately, NO.
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calibos
Carpal Tunnel
   
Reged: 11/18/07
Loc: Ireland
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Re: So frustrated i could just cry....
[Re: dan777]
#5015029 - 01/13/12 08:40 AM
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The best of us are capable of having Homer Simpson 'Doh' moments. I don't suppose you forgot to put one of the plates back on or maybe put both plates underneath the roller or both on top of the roller. Without the plates sandwiching the roller the roller bearings will dig into the formica.
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tubehead999
professor emeritus
   
Reged: 11/25/08
Loc: Kennesaw, GA
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Re: So frustrated i could just cry....
[Re: dan777]
#5015030 - 01/13/12 08:41 AM
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I know it is a pain...But you are going to have to pull that monster apart to see what is up...
If the bottom platter has warped: I used to have a Starfinder 16 with the warped baseboard issue. I replaced the bottom platter with one of the wooden, unfinished tabletops from Home Depot. Lowe's carries them as well. The diameter of the tabletop is larger than the bottom platter by several inches, if clearance is a consideration.
Best of luck.
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gnowellsct
Postmaster
   
Reged: 06/24/09
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Re: So frustrated i could just cry....
[Re: tubehead999]
#5015060 - 01/13/12 09:14 AM
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I know it is a pain...But you are going to have to pull that monster apart to see what is up...
If the bottom platter has warped: I used to have a Starfinder 16 with the warped baseboard issue. I replaced the bottom platter with one of the wooden, unfinished tabletops from Home Depot. Lowe's carries them as well. The diameter of the tabletop is larger than the bottom platter by several inches, if clearance is a consideration.
Best of luck.
That is brilliant. One of the things about dob guys: any ol' piece of junk becomes a ticket to the sky.
That's much more resourceful than using cardboard and duct tape to make end caps. But then, I'm not a dob guy.
GN
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gnowellsct
Postmaster
   
Reged: 06/24/09
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Re: So frustrated i could just cry....
[Re: tubehead999]
#5015061 - 01/13/12 09:14 AM
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I know it is a pain...But you are going to have to pull that monster apart to see what is up...
If the bottom platter has warped: I used to have a Starfinder 16 with the warped baseboard issue. I replaced the bottom platter with one of the wooden, unfinished tabletops from Home Depot. Lowe's carries them as well. The diameter of the tabletop is larger than the bottom platter by several inches, if clearance is a consideration.
Best of luck.
That is brilliant. One of the things about dob guys: any ol' piece of junk becomes a ticket to the sky.
That's much more resourceful than using cardboard and duct tape to make end caps. But then, I'm not a dob guy.
GN
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cliff mygatt
Pooh-Bah
Reged: 01/27/09
Loc: Kitsap County, WA
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Re: So frustrated i could just cry....
[Re: gnowellsct]
#5015105 - 01/13/12 09:41 AM
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Carol, one of the members of my club has a 12 inch LB and he had horrible motion in azimuth. It turned out the base got wet and warped. So, the easy solution while in the field was we took the board off and flipped it over swapping all the hardware from one side to the other and it worked like a champ and he is a happy observer once again. Good Luck.
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Carol L
   
Reged: 07/05/04
Loc: Tomahawk, WI 45N//89W
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Re: So frustrated i could just cry....
[Re: cliff mygatt]
#5015206 - 01/13/12 10:43 AM
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Joe, the azimuth was fine in the shed just before the scope was disassembled a few days ago, and the roller bearings are in excellent shape, no rust or anything to stop/slow them. I'll try testing the boards with a straight edge.. hadn't thought of that, thanks. 
Barry, the roller bearings and plates are really clean. In fact, i cleaned everything prior to re-assembling the scope. Funny you should mention the spray silicon, though. Late last Spring i sprayed some on the roller bearings and i guess some dust got in there during the Summer, because when i disassembled things to put in the DSC pivot hardware, i noticed a tiny bit of 'gunk' on the individual bearings. It took about 1/2 hour to get the stuff off.. i literally had to rub and rub all sides of each bearing in order to make sure they were clean. Then we put the LTA back on the base and saw how difficult it was to turn the scope, and my husband said it because there wasn't any lubricant spray. But that didn't make sense, because there was none there when the scope was new and it worked fine. I thought there might be some soap residue, so i took it apart and cleaned it again, and at my husband's insistance, sprayed some silicon lubricant on the pristeenly clean bearings... no change at all. The bearings moved/sounded like new whether they were clean or sprayed.. no difference at all. He even splayed his hands across them and pushed down on the upper plate while turning it and it moved like it was brand new. It begins to bog down when the boards are put together, and becomes really hard to move when the weight of the LTA is added. I'll clean the bearings and plates off again but i'll use alcohol this time... after i sprayed the silicon on things, my husband insisted on adding WD-40 to the mix.. that didn't work either.
Dan, that's what i was dreading. 
Keith, i've done some doozies in my time, but things were as they should have been.. the bearings were properly sandwiched between the plates.
Bob, we took it apart and put it back together about 8 times trying to figure this out. At this point i'm guessing a whole new rockerbox is in order. Thanks for the info about the table top though, what a great idea!
Cliff, that's brilliant! How did you switch those three pads of plastic (teflon?) from one side to the other, though? They look like they're attached with a pretty good-sized staple gun.
Some miscellaneous thoughts... My Son said something interesting after i'd posted. He used to tinker with audio stuff and said that a speaker box (also made of particle board) acted up one winter after he brought it inside from the car. He'd just bought it but had left it in the car until he made room for it. So i'm guessing that the sudden warmth of the house caused the particles in the scope's wood to swell enough to cause havoc. I guess that was my 'Homer moment'... not wrapping the rockerbox in plastic bags before bringing it inside the house. 
So i guess the next question is.. does anyone know of a supplier of 16LB rockerboxes and baseboards?
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Doug Culbertson
Post Laureate
   
Reged: 01/06/05
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Re: So frustrated i could just cry....
[Re: Carol L]
#5015218 - 01/13/12 10:48 AM
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It's not exactly cheap, but Dobstuff does LB rockerboxes and groundboards.
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MrJones
Pooh-Bah
  
Reged: 09/15/10
Loc: Indiana
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Re: So frustrated i could just cry....
[Re: Carol L]
#5015221 - 01/13/12 10:49 AM
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That's a sad story.
I don't have much to add other than I know dobstuff.com sells nice looking rocker box kits for the LB16 that won't break the bank.
Oh and here's a fairly recent CN thread on it link
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cchapkido
sage
Reged: 02/25/10
Loc: MA
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Re: So frustrated i could just cry....
[Re: Carol L]
#5015258 - 01/13/12 11:08 AM
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So i guess the next question is.. does anyone know of a supplier of 16LB rockerboxes and baseboards?
Hey Carol,
Even without woodworking experience you should be able to pull the base apart and use it as a template on some nice plywood. Don't think of it as a major project, think of it as cut -n- trace.
I'm about to do the same thing with my 12 inch orion for the same reason, swelling in the baseboard.
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saxmaneagle
sage
Reged: 08/21/07
Loc: Saint Francis, MN
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Re: So frustrated i could just cry.... *DELETED*
[Re: cliff mygatt]
#5015264 - 01/13/12 11:10 AM
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Post deleted by saxmaneagle
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coopman
Carpal Tunnel
   
Reged: 04/23/06
Loc: South Louisiana
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Re: So frustrated i could just cry....
[Re: saxmaneagle]
#5015339 - 01/13/12 11:49 AM
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Did you try to peek between the ground board and the rocker bottom to see if the two are rubbing each other somewhere? They must be in serious contact with each other to make it so hard to turn.
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Slartibartfast
sage
Reged: 05/28/08
Loc: New Jersey
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Re: So frustrated i could just cry....
[Re: coopman]
#5015520 - 01/13/12 01:48 PM
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You could try removing the teflon pads altogether and see if the motion loosens up with the entire weight on the roller bearings. (I've been thinking of doing this with mine - my AZ motions have been pretty stiff since day 1).
If something warped, it sounds like all the weight is now on the teflon pads and none of the weight is on the roller bearing (since you can't hear the roller bearing make the rolling noise anymore). You could try inserting some kind of spacer between the top plate of the roller bearing and the bottom of the rocker box to take some weight off the teflon pads and put it on the roller bearings.
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starbob1
scholastic sledgehammer
Reged: 03/11/07
Loc: IN
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Re: So frustrated i could just cry....
[Re: Slartibartfast]
#5015593 - 01/13/12 02:43 PM
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I would get the Dobstuff rocker box kit.That would really give you a great box that will last forever.The price is a very good deal.In fact the price of the LB16 is so cheap I was thinking of getting one and scrapping the bad parts and build a new scope with the good parts and hopefully good optics.It would still be thousands less than a new obsession or starmaster or any other premium scope maker.
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hudson_yak
Carpal Tunnel
Reged: 11/15/07
Loc: Hyde Park, NY, USA
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Re: So frustrated i could just cry....
[Re: Carol L]
#5015613 - 01/13/12 02:53 PM
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Where are the teflon pads relative to the wheelybar arms? You'll get differing amounts of load being carried by the pads relative to the roller bearings depending on whether the pads are over the arms or midway in between them since under load the groundboard flexes a bit. The pads would be carrying the most load if directly over the arms, the least if midway between.
Maybe after installing everything it's positioned differently than it was before.
Mike
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Carol L
   
Reged: 07/05/04
Loc: Tomahawk, WI 45N//89W
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Re: So frustrated i could just cry....
[Re: hudson_yak]
#5015640 - 01/13/12 03:13 PM
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Thanks for the links, Doug and Mr. J. Wow, the Dobstuff box is gorgeous, and it's a good price, too. The close-ups in the CN thread really show off the details. I also like the fact that the Lightbridge page mentions the Sky Commander, and also says to use, my rollerbearings ("pin bearing lazy susan") from the scope. If i purchased the kit though, my only concern would be that the rockerbox is 21 3/8" x 21 3/4" and the circle on my 16LB JMI wheelybars is 27" but i'm sure we can figure it out pretty easily.
'cchapkido', my husband built our house, so what you suggested would be a walk in the park for him. But winter in northcentral Wisconsin isn't the time of year to set up the woodworking equipment in the unheated garage, so we'll probably use Bob's idea of using a tabletop from Home Depot, or i'll just get a kit from Scopestuff. You mentioned 'swelling' of the board. I think that better describes the word 'bowing' that i used. Hindsight being 20/20, the invasive house condensation/moisture probably entered the board(s) on the outer edge, and the pivot hole. If both areas 'swelled' even just a bit, that would account for the rubbing of the pads on the outer edge, and the tightness of the pivot bolt no matter how loosely it was adjusted. There's no visible damage to the boards, but at this point i think we're resigned to the fact that they need to be replaced. One thing for sure, i'm glad this kick in the teeth didn't happen just before a major week of drop dead gorgeous skies.
Scott, your story sounds so familiar to others i've read regarding the LB's base. There's no damage to my plates or roller bearings, so i'm good there. TBH, if you saw my baseboard and groundboard, you'd swear the scope was only a few months old, that's how near-pristeen they are. They've never sat on the ground because they're always high and dry on the wheelybar. I'm quite sure by now that my problem occurred because i didn't enclose the rockerbox in plastic before bringing it inside, and the particle board 'swelled' just enough not to be seen visually, but to disallow smooth azimuth motion. That being said, i'm sure glad my 'Homer moment' merely affected the rockerbox and not the mirror. As you said, we bought these big scopes knowing that they'd probably need attention at some time, and aside from this one boo-boo of mine, Seymour has brought me plenty of 'wow' moments i'll never forget. And i'm glad to know that i'm not the only one who 'giggles at the eyepiece'... well said. And oh, how true! 
Clay, there's 1/8" between the baseboard and groundboard but it was enough to see that the rollerbearings were indeed moving. But the pads on the top of the groundboard appeared to be in constant contact with the bottom of the baseboard, which indicates swelling around the outer edges of one or both boards.
Bart, i'm glad you mentioned totally removing the pads, my husband suggested that very thing this morning. But coward that i am, i figured they were there for a reason and i'm hesitant to remove them. BTW, why are they there if there's a rollerbearing? Regarding your suggestion of a spacer between the top plate and baseboard, wouldn't it cause excess pressure on that particular area of the rollerbearing? I know the plates are metal but I read the The Princess and the Pea.. sometimes a small thing can create big problems.
starbob1, i'm personally leaning towards getting the Dobstuff kit. Not only is it gorgeous, but i'd just like to "get 'er done" and hit the sky.
Mike, the wheelybar for the 16LB is circular, so the weight would have been evenly distributed around the outer edge of the boards. I had the scope off of the wheelybar in late spring when i took everything apart to spritz some silicon spray on the roller bearing, and when it was put together again my present problem didn't exist. I'm betting the particle board swelled a bit when i brought things inside.
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hudson_yak
Carpal Tunnel
Reged: 11/15/07
Loc: Hyde Park, NY, USA
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Re: So frustrated i could just cry....
[Re: Carol L]
#5015667 - 01/13/12 03:37 PM
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Mike, the wheelybar for the 16LB is circular, so the weight would have been evenly distributed around the outer edge of the boards. I had the scope off of the wheelybar in late spring when i took everything apart to spritz some silicon spray on the roller bearing, and when it was put together again my present problem didn't exist. I'm betting the particle board swelled a bit when i brought things inside.
Ah, ok, I see that now. Still, I think it's worth some time repositioning it to see if the behavior changes. I added a scopestuff teflon pad+ring to my LB to tighten up the feel. I have to shim the roller bearings with a few layers of paper to get the turning resistance I want. Just one thickness difference of a layer of regular paper is enough to change the turning resistance significantly. The wheelybar looks like it could flex a little under load and it may not be an absolutely perfectly flat ring either.
Just a thought before you go to too much trouble...
Mike
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