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Jazzing up a Xt10i

Started by RUSTY845, 10/04/2005 05:19PM
Posted 10/04/2005 05:19PM Opening Post
Hi All; I have a Orion XT10i Dob it's about a year old now and I was thinking of trying to jazz it up a bit. although the movement of the dob base is ok it not great, I put some ebony star on it but it's still not what I'm looking for. The weekend before last I was at a small star party, someone had a home made dob and it moved like glass. Is there any way I can get the Oran to move like that.... ? or do I need to build a new base... if so where can I get the plans. The scope is my ten year old daughters so ease of movement is impotent

Thanks for any help you can give.

Bob.

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Posted 10/04/2005 05:44PM #1
If you did the Ebony star/teflon thing it should have good motion. If you did not replace the telfon/plastic bearing material when you did the Ebony star, I would do so...

jon
Posted 10/04/2005 05:59PM #2
Are you complaining abount altitude (side bearings) or azimuth (bottom)?

And when you did the ebony star, did you also replace the teflon pads which ride atop the formica?

In terms of altitude, moving the bearing pads away from the bottom of the semicircle on the base("under" the altitude bearing) farther up the semicircle will increase the friction. The reverse is also true. In terms of azimuth, you want the pads near the edge for stability reasons.

Some scopes (which I have seen only online) use a combination of roller bearings and pads to reduce friction still further. I have no idea how well that works. But you could put a heavyweight lazy susan-type mechanism (between rocker box and ground board) to support the bulk of the scope and use screw-adjustable pads to fine tune reistance.

You may also have played with a near-perfectly balanced dob. If you have it balanced, you have the ability to have much lower friction in altitude than if it is unbalanced. This can translate to 'smoothness'. Have you checked your balance recently? Installing a counterweight (or a counter weight system) may help.
Posted 10/05/2005 08:05AM #3
for the alzimuth motions, make sure you have that nut real loose if its anything like the original XT (the nut should put ZERO force on the lower piece and could even have 1mm or more of slack)...

As for the altitude bearing, since you have the XTi version, you could loosen the knobs and balance the scope better. I'm not sure exactly how the XTi bearing surfaces work, but on my XT the bearings are plastic bearing to plastic hub, and after I replaced the plastic bearings with PTFE bearings, it just did NOT work - next to no stictation. PTFE just does not work will on the plastic hub. Probably needed ebony star there too (but too much work for adding ebony star on altitude surface). ... so i had to put the plastic stuff back...

But the alzimuth, ebony star and PTFE or teflon works well with the VERY loose nut...