sabir
professor emeritus
Reged: 06/23/07
Posts: 698
Loc: Pune (India)
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I thought I’d finally get down to it and start this thread, which I’ve been planning to start since a few days. I’ve read about this mod. being done by several people but I was unable to find sufficient data dealing with this topic, particularly for intelliscopes
So here are a few questions I have from the top of my head...
1. I’ve read that installing a Lazy Suzan bearing makes the azimuth movement too free (weather wane syndrome!  ) and hence some sort of friction mechanism needs to be employed. I know the light bridges use a spring loaded center bolt for varying tension, but this obviously cannot be used for the intelliscope... so any ideas which work would be really welcome.
2. I have read that the ball bearings have a tendency of developing flat spots, making it a click-stop azimuth. For all the people who have installed these bearings and have been using them for a while... How are the bearings holding up??
3. If flat spots are posing a problem, has any body experimented with cylindrical bearing surfaces as opposed to ball bearings i.e. line contact as opposed to point contact??
4. After installation of these bearings, does the scope become sensitive to the leveling conditions of the ground?? I intend to use the scope with a Round Table Platform down the road. Would this pose to be a problem??
5. Finally, sourcing these bearings. I have found several vendors who offer similar bearings i.e. 12” Dia, and 5/16” overall thickness. Are these the ones to be used with the intelliscopes? I would like to find a bearing, which has the right thickness for the intelliscope to work without the encoders requiring shimming...if possible
Here are the links I found:
http://doitbest.com/Kitchen+organizers--model-212482-doitbest-sku-212482.dib
http://www.rockler.com/product.cfm?page=2273&filter=lazy%20susan
http://www.rockler.com/product.cfm?page=2273&filter=lazy%20susan
Here is another great link for all intelliscope systems. It has all the information on the intelliscope system you’ll ever require and more!! 
At the bottom of the page there is a drawing giving all the dimensional details required for the azimuth assembly.
http://maxwell.fief.org/intelliscope.html
I would encourage everybody, especially the path beakers who have pioneered this mod. to participate in what ever way possible be it pictures, links, suggestion or advice and hope fully, with your help we can make this a one stop thread for the Lazy Susan mod for intelliscopes and by and large for all dobs.
Thank you all!
Sabir 
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No one can attain good livelihood-even if he is so lucky - without passing through misfortunes. Days will usurp the opportunities of those who waste today's opportunity due to their expectation of tomorrow's opportunities. Day's custom is the usurpation of opportunities and the habit of time is wasting them.
Imam Ali (a.s)
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epee
professor emeritus
Reged: 11/30/06
Posts: 697
Loc: Suh-van-nuh, Jaw-juh
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I've installed the "Do it Best" bearing on my XT12i. While this is a new mod for me and I can't answer regarding long-term use the thickness was perfect, at least for my encoder. It does make the azimuth too easy and some form of braking is needed in addition to the lazy susan bearing. Right now I'm experimenting with center bolt and I'll go into more detail if that works out. I know leaving the teflon pads installed will add considerable friction to the movement so perhaps leaving one or two might be the right answer.
As far as the lazy susan bearing developing flat spots over time; I'm not sweating that. The bearing, once placed is easy and cheap enough to replace.
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Jim Girardeau
Orion XT12 Intelliscope
Celestron 11X80mm binoculars
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Buck
professor emeritus
Reged: 04/29/05
Posts: 570
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To add a little drag to the AZ movement you can use a few small pieces of cut loop carpet to the bottom of the rocker box. Just trim the carpet till it is still a bit much and it will ware-in in a short while.
Buck
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sabir
professor emeritus
Reged: 06/23/07
Posts: 698
Loc: Pune (India)
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Hi Jim,
I too am looking the "do it best" bearing as they also stock the #08200 magicsliders (I plan to use these a the breaks) which saves me shipping and are supposed have the right height for the intelliscopes. I'm really glad to hear that you found the thickness to be perfect!!
Have you tried using your XT12i on a sloping surface after the mod? I would like to find out if the shift in the center of gravity of the scope due to the slope has any effect on the performance of the bearing.
Do keep us updated on how your break mechanism goes.
Thanks again,
Sabir
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No one can attain good livelihood-even if he is so lucky - without passing through misfortunes. Days will usurp the opportunities of those who waste today's opportunity due to their expectation of tomorrow's opportunities. Day's custom is the usurpation of opportunities and the habit of time is wasting them.
Imam Ali (a.s)
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epee
professor emeritus
Reged: 11/30/06
Posts: 697
Loc: Suh-van-nuh, Jaw-juh
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I've not tried my scope on a sloping surface. I live along the coast and you have to look for something other than flat ground. I've no doubt that the lazy susan bearing by itself will allow the scope to both blow in the wind and point downhill.
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Jim Girardeau
Orion XT12 Intelliscope
Celestron 11X80mm binoculars
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DanJ
Pooh-Bah
Reged: 12/01/04
Posts: 1088
Loc: Youngsville, NC
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Sabir,
The 08200 Magic sliders will do the trick. They continue to work great on my xt8i and I have been using them for almost two years now.
Cheers,
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Dan J.
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XT8i
ETX 90
PST
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"A government big enough to give you everything you want, is strong enough to take everything you have."
Gerald Ford
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Jim7728
Postmaster
Reged: 04/10/05
Posts: 5063
Loc: Stoop Landing Observatory, NYC
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Sabir
I've used "lazy susan" bearings for my homemade dob base.
I had the first one you listed:
http://doitbest.com/Kitchen+organizers--model-212482-doitbest-sku-212482.dib
And it work fine(smooth motions) for a few years until one or two ball bearings got out. I've since went with a better quality 12.75 "Lazy Susan $22.50
Aluminum Lazy Susan Bearings
This one feels a little smoother and better built than the $10 one. No issues with the weathervane effect, but my 12.5" sonotube dob is heavier than the Intellescope metal tube and like Buck said, if you want to add resistance, a piece of carpet or felt will work fine.
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Jim
Genesis SDF-f/5.4 FS-102-f/8
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Bob W6PU
Carpal Tunnel
Reged: 12/23/04
Posts: 2200
Loc: Springer-N.E.NM
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The main problem, as I see it, with modifying the Az on the Intelliscope base is that if you get it wrong, and the Az encoder disc magnetic strip comes into contact with the encoder board, you immediately wipe out the two tiny electronic sensors that protrude slightly above the Az board!
The working clearance between the magnetic disc strip and the two electronic sensors is of extremely close tolerance anyway,for this system to operate properly, and there just isn't any margin for error.
This catstrophy occurs without any warning the instant that you rotate the base! The two tiny sensors, look like two black dots and are micro soldered to the Az board circuitry.
These are so delicate that they are actually wiped clean off of the Az board and usually leave a scrape in the Az disc black
strip. A new Az board and possibly a new magnetic disc must be ordered from Orion, as the COL function is now inoperative...Been there, Done that...LOL!
Just scratching the magnetic strip on the Disc. won't hurt it, but if you've bent the disc badly, you either have to try and straighten it out, or just order a new disc, along with the new Az board.
Two simple raised barrier strips, just a hair higher than the sensors, and glued to the board adjacent to each of these two miniature electronic sensors would eliminate this problem,making it physically impossible for the Disc strip to come into contact with the two sensors . A tiny piece of hard plastic or other non magnetic substance would do the trick!
I did contact Orion Tech support suggesting this fix, but I don't know if they passed the Info. on to the Mfg. of the Az board.
Bob
12" F/4.9 Intelliscope with COL
10" F/5.0 Coast Inststrument Treckerscope,circa 1956
Stratus 35mm( hand grenade ) Nagler 22T4, 17T4, and 12T4
BO/TMB 7mm and 5mm, TeleVue Paracorr.
Barlows: GSO 2"ED 2x, Orion Shorty Plus 2.2X, TeleVue 2.5x, Coast Inst. 3x
Edited by Bob W6PU (05/22/08 01:41 AM)
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Bob W6PU
Carpal Tunnel
Reged: 12/23/04
Posts: 2200
Loc: Springer-N.E.NM
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After re reading my post of last night, I want to add this.
I think that Before anyone does any serious base modification that will alter the spacing between the Az encoder board sensors and the magnetic disc, that they really examine and get to throughly understand the mechanical relationship of the rotating disc and the pick up sensors.
Hold the board in your hand and observe how the magnetic disc rotates above the sensors on this board, and note how close the disc magnetic surface normally comes to touching these Az board sensors!
After reading this long thread, I was frankly amazed that no one has picked up on this very common problem, and added any comments!
It makes me wonder just how many have actually done any serious modification to the Intelliscope base azimuth movement, such as adding a roller bearing system to replace the existing Teflon Az sliders.
I have done so, but have found that the adjustment of same is so critical to avoid damage to the azimuth board sensors, that I will not post this Mod.
The problem that I described is an accident just waiting to happen, and should probably be permanently attached to this Reflector Forum!
I hope that I've helped some Intelliscope owners from damaging their COL function!
Cheers
Bob
Edited by Bob W6PU (05/22/08 01:43 PM)
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jayscheuerle
Post Laureate
Reged: 01/16/06
Posts: 4063
Loc: S. Philadelphia, PA
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Quote:
I would like to find out if the shift in the center of gravity of the scope due to the slope has any effect on the performance of the bearing.
My LB has roller bearings. Before I had it properly balanced (and relied on the brake to hold it), the scope would rotate its nose to the low point on my EQ platform. Once balanced, this no longer occurred.
The LB ads tension to the rollers via the center hub-nut. There's a large knob on top. Just righty-tighty when it's windy.
The scope's a pleasure to move. - j
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Fight indignorance!
The Green Goblin - 12" of dobsonian excellence!
The PortaBowl-a $100 4.5" f/8 ball-scope YOU can build!
Eero2-a 6" f/5 ball-scope you probably can't. 
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dmgriff
sage
Reged: 09/20/06
Posts: 332
Loc: 30 degrees latitude, USA
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I used a lazy susann similar or same to the doitbest 12" on a 6in dob no col. I found the movement sporadic at best, the ball bearings tended to bunch up, and teflon spray did not stop the bunching. I did not try any thick grease as I did not want to attrack dirt.
Went to new Virgin Teflon pads on the 6. Works well.
Several vendors have been offering virgin teflon pad and true ebony star laminate kits (one among them is scopestuff.com az kit ). There have been some threads in CN forums about applying ptfe pads and ebony star to xti intelliscopes with col.
Just my opinion, but, I think the ptfe and ebony star will give you custom dob az motion, as many use it for the az, and ebony star laminated to the alt beartings.
I just never had any luck with the hardware lazy susann approach, it may have been the weight of the 6in, dont know.
Good viewing,
Dave
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epee
professor emeritus
Reged: 11/30/06
Posts: 697
Loc: Suh-van-nuh, Jaw-juh
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I have ripped up the board sensors trying the "CD on the center bearing" trick but now I'm older and wiser. BTW, three cheers for the Orion support team who sent me a new AZ encoder assembly free of charge (I can imagine them saying, "yep another one tried the CD").
I measured the thickness of the teflon pads and work within plus or minus a baby's hair of that. So far so good.
It sounds as if DMGRIFF may have gotten a bad bearing. Another possibility is that it is not centered and so begins to bind through some of it's travel. I was concerned about lubricants holding dirt also and used graphite dust (look at a sewing shop) to lube the susan bearing and that seemed to work just fine.
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Jim Girardeau
Orion XT12 Intelliscope
Celestron 11X80mm binoculars
Edited by epee (05/22/08 05:24 PM)
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dmgriff
sage
Reged: 09/20/06
Posts: 332
Loc: 30 degrees latitude, USA
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epee,
Measured it as best I could, clickity clack movement, at best. Just my personal experience.
I have the gso roller bearing system on a DSH10, and it is not a lazy susann type mechanism, very smooth.
I have tried every inexpensive hardware store mod from gliders, amourall lube, teflon spray, and the lazy susann and none, absolutely, none, work for me.
At 10usd or so the lazy susann is easy enough to install for experimentation, though.
Good viewing,
Dave
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epee
professor emeritus
Reged: 11/30/06
Posts: 697
Loc: Suh-van-nuh, Jaw-juh
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I understand. It seems that virgin teflon solved it for you. The bearing I'm using is certainly smooth enough; now I need to create a touch more sticktion. If I have too much trouble doing that it's the laminate kit for me.
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Jim Girardeau
Orion XT12 Intelliscope
Celestron 11X80mm binoculars
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dmgriff
sage
Reged: 09/20/06
Posts: 332
Loc: 30 degrees latitude, USA
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The felt furniture pads will definitely cause sticktion. Maybe too much.
Good viewing,
Dave
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Bob W6PU
Carpal Tunnel
Reged: 12/23/04
Posts: 2200
Loc: Springer-N.E.NM
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Quote:
I have ripped up the board sensors trying the "CD on the center bearing" trick but now I'm older and wiser. BTW, three cheers for the Orion support team who sent me a new AZ encoder assembly free of charge (I can imagine them saying, "yep another one tried the CD").
A CD or "milk jug" washers on the center bearing can be disastrous when used on the Intelliscope center bearing as any slight amount of over thickness causes a "high centering" condition that allows the upper half of the XTi base to rock or wobble in respect to the fixed lower base section!
This results in a off center pressure on the edge of the magnetic disc which then presses against the two Azimuth Board Sensors and tears them right off of the board!
I would never again replace an azimuth board without first protecting those two electronic "black dot" sensors with something like a glued on thin non magnetic washer that physically prevents the sensor from making contact with the magnetic disc!
One way of dealing with dealing with any wobble or rocking of the two base sections is to leave just enough thickness in the three Teflon base pads so that a "lazy susan" bearing assembly is taking most of the weight, with the base edges just barely "grazing" the three Teflon pads.
Those two raised "black dot" sensors on the Az board are an inherent design weakness in this system, and I just can't understand why the Mfg. continues to make the Az board this way, if indeed they still do?
Oh yes, ditto on the understanding Orion Tech Support Team.
I must have replaced three AZ boards within a couple of months, before I "wised up" as to what was going on, and what to do about it...I felt like a complete idiot, and offered to pay for the new boards, but as my scope was still less than a year old, they wouldn't take my money!
I sure hope that my Azimuth Board design change suggestion was passed on to the Mfg of those boards, this was around last Sept and Oct.
Cheers!
Bob
Edited by Bob W6PU (05/22/08 07:36 PM)
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chalker
professor emeritus
Reged: 09/14/05
Posts: 604
Loc: Ontario, Canada
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Quote:
.... I've since went with a better quality 12.75 "Lazy Susan $22.50
Aluminum Lazy Susan Bearings
This one feels a little smoother and better built than the $10 one.
Boy the second aluminum bearing you linked to looks nice. I wonder what the internal diameter is, since it has rotating rings written all over it.
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Orion StarMax 127
Meade Lightbridge 10" Deluxe
Toronto CSC
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calan
sage
Reged: 06/16/07
Posts: 457
Loc: Oklahoma City, OK
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Wow... I just posted about this in another thread. Should of known I wasn't onto something original 
I used the standard Lazy Susan bearing, lubed with some silicon spray. Adjusting the amount of "freedom" is simple; Place a nylon spacer and/or washer on the center shaft so that it that sits about 1/64" below the top of bearing (use a straight-edge across it). You want the spacer to be barely below the base (about 1/64"). Then put a big fender washer under the lock nut on top of the base to help spread out the nut's clamping force a bit.
You can then slightly tighten the lock nut (and thus transfer friction from the nut/shaft to the base) to get any amount of drag you desire. If you keep tightening, you will begin to tighten the base down onto the spacer, producing even more drag without crushing the bearing or cracking the base. I can adjust mine from extremely free spinning to almost locked down.
Edit:
I just checked the links and the "doitbest" version is the one I've had kicking around in my garage for years and the one that I used.
BTW - These things are rated at 1000 lbs, and the load is spread out over many ball bearings. Unless it is severely over-loaded, abused, or defective, I can't see it developing flat spots any time soon. Time will tell though
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epee
professor emeritus
Reged: 11/30/06
Posts: 697
Loc: Suh-van-nuh, Jaw-juh
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It sounds as if you've done something similar to what I'm planing but can you explain that, "1/64" below the top of the bearing" a little clearer please?
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Jim Girardeau
Orion XT12 Intelliscope
Celestron 11X80mm binoculars
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epee
professor emeritus
Reged: 11/30/06
Posts: 697
Loc: Suh-van-nuh, Jaw-juh
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Calan,
So let me see if I've got this right. You've placed a nylon washer on top of the brass center bearing so that it comes to just below flush with the base. The lock nut then presses a fender washer down on the nylon washer to produce the friction you want?
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Jim Girardeau
Orion XT12 Intelliscope
Celestron 11X80mm binoculars
Edited by epee (05/23/08 10:59 PM)
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