Ovision worm backlash adjustment

Jun 11, 2008



#37837 Jun 11, 2008

Having completed my Ovision worm tests I decided last night to adjust

out most of the backlash. The Gemini system needs backlash; I don't.

It turns out that the adjustment operation is MUCH easier with the

Ovision than with the default worm block set up.

I think this is for several reasons. First of all there's no squish in

the system. That means where you set it is where it is, whereas with

a bit of slop in the worm blocks where you set it is not necessarily

where it is.

Let me put this another way. You've got a worm, there is a bit of

play in the bearings and the blocks. So, now, you adjust the

position, but as the worm turns and shifts the "feel" gets looser and


I think this is *part* of what people like myself were trying to

adjust out when we laboriously cranked through the entire worm gear

testing for high spots to reduce play.

What I noticed last night was that there was *some* differences

depending on what part of the worm gear was engaging the worm, but not

nearly as much as I had encountered when trying to adjust the worm blocks.

Now this might be due to a lot of things, including seven years of use

since the last time I messed with the worm adjustment.

However, it seems to me that the very rigid positioning of the Ovision

makes the adjustment process easier and that the net effect is less

variability in the backlash adjustment as the worm gear turns round

the worm.

This means that part of the system's advantage lies in an improved,

easily adjusted, and less variable backlash adjustment. I don't know

how many visual observers are willing to pay $500 for that, but it

makes life a lot easier, and it means, among other things, that as the

mount turns you don't hit a "loose spot" that's as exaggerated as


That's the way it seems now anyhow.


Greg N

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