2" shaft equatorial mounting Pt 13: Back to basics:

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The need to unload the single flange supporting the entire weight of the OTA, counterweights and Declination assembly required a rethink. I have now placed the loads between two flange bearings. The plywood laminations under compression from studs [threaded rod] pressing the flange bearings together is back on the drawing board.

Here are couple of simple drawings using SketchUp for the first time:

The width of the Declination axis 'box' will be set to allow clearance of the OTA from the mounting and wormwheels. The Dec housing can be bolted right through the PA housing with studs to ensure maximum stiffness and strength.

Lead can be added to the rear of the PA 'T' form to balance the offset Declination axis and the weight of OTA. Though this will have no effect on the OTA's own balance point. The end to the 'T' must clear the mounting frame. I have set the drawing of the mounting to 55° to match my own latitude. A curved base to allow fine adjustment might follow.

In hindsight I should have built the detail onto the axes before adding the mounting and Polar Axis construction. Trying to add these details later was beyond my rudimentary skills with SketchUp.

I hope this new design lies well within the skill levels of any handy telescope maker. Hopefully providing a sturdy mounting capable of carrying long and heavy refractors without heavy expense.

More to follow when I had a chance to fine tune the design. I spent far more time undoing silly mistakes than actually drawing but it does start to go quite quickly with practice.
I can already see that the forward extended Declination 'T' can have the studs overlapped with the PA housing to reduce the degree of overhang. Though this might result in considerable complication in the 'woodwork' to achieve this.

A contact has kindly pointed out that during a meridian flip the counterweight must pass through the Polar Axis support frame. Here is a drawing with a clearance circle superimposed on the mounting. Shortening the declination shaft to match will require a much heavier counter balance weight.

Click on any image for an enlargement.

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