Planning Equatorial Platform Build

[Jim-a]

I'm thinking about building an Equatorial Platform for my 12" Lightbridge.

So far I have decided to go for a Vertical North Segment design. Whilst its going to mean a more difficult surface to shape, I'm guessing that the benefits of being able to mount the north rollers horizontally will make it worth it.

I've got some initial questions that hopefully someone can point me in the right direction on...

1. One thing I can't work out from reading the various posts on here and the ones on the yahoo eqplatform group is where the baseline of the cone should intersect the south segment... I've drawn what I think is probably right here (greatly exaggerating the width of the segments)...

.. but would be massively grateful if anyone who has built one can confirm that I'm right.. or put me straight.

2. From a quick search it seems that there are about a billion different types of bearings available... has anyone got any recommendations?

3. Does anyone know where the Centre of Gravity of a 12" Lightbridge is - I'm assuming its an inch or two below the center of the elevation pivot - but I don't know how critical it is to get it spot on.

4. I'm planning on using a slow rev motor (possibly geared down) with a PWM speed controller - and directly driving the north segment with it (as opposed to a threaded rod type drive, which seems a bit fiddly to me) - does anyone have any tips there?

Sorry... thats a lot of questions I know - any help gratefully received.