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It's as simple as this. You have a 3 tripod legs connected to a plate that holds them together. Rock solid. Alternatively you have a column type pier that is suitably sized to be rock solid. The plates on top of these can be levelled to pretty close to horizontal. Any other accurate levelling is taken care of when you polar align your mount.
You have a mount and telescope sitting on top of that. Rock solid.
If you then put 3 slender bolts with inadequate stiffness between the 2 rock solid parts, you've created a potential zone of weakness. Critical in that statement are the words "slender", "stiffness" and "potential." So it's not to say that you can't do it, as there are obviously people who have done this and used with success.
Slenderness is a function of the bolt diameter and length. Stiffness is a function of bolt diameter, length, and material properties. So there's going to be some point where you've got a short enough and/or large enough diameter bolt where the effect of using them is negligible. The fact that they're there means they will always be a little more potential for weakness, just a matter of how much.
But at some point you will be either too long or too small a diameter bolt for that length, and it will noticeably be a weak point in your train.
So all I'm wondering is, as long as your pier/tripod is close to level, and your mount can be polar aligned on top of that, what's the point of introducing a potential zone of weakness. When I'm using the term "weakness", I'm not saying the whole thing will collapse (although if you had some huge/heavy PME and massive RCOS on top etc, I would certainly be checking the bolt length), but I mean movement, vibration etc that are critical for astroimaging etc.
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