EQ3-2 Mount Tune-Up (Part Two)

Whilst I had the mount on the bench I thought I’d have another look at what seems to be a perennial problem with the Skywatcher mounts at UK latitudes: the mounts are at the limits of their design spec. for the alt adjustment which regularly results in problems with the south side bolt bending or running off the adjustment cam, or both (as in my case).

I’d already had the south bolt out to straighten it and not been at all happy with the way the bolt worked since. I know that some people have fixed an extra piece of stainless sheet over the cam with epoxy resin effectively making it harder and longer, but having gone to the trouble of cutting some suitable sheet up I decided that it that doesn’t seem like entirely the right solution. It struck me that what’s required is some sort of “tappet” that rides on the cam and is free to rock as it changes angle relative to the bolt, preventing the bolt being loaded sideways. In a box of plumbing bits I found a 10mm brass end cap and an 8mm olive that would fit inside it nicely. (You can see them in the bottom left of the photo.) The bolt fitted inside the olive with some room for the end cap to rock, though not much. I made obeisance to the Greek Goddess of Adhesives, Araldite, and used a little to fix the olive inside the end cap. I then fiddled the entire thing onto the end of south side bolt so it rests on the alt cam.

Whilst it’s an improvement, it’s not a big improvement and I’m not entirely happy with it. I’m now thinking that what’s probably required is a block with a dished centre to be fixed to the back of the came so the bolt always bears in roughly the same place and can’t slide down the cam as it moves further away. It’s more tricky to do, too. Of course what’s really required is for Skywatcher to redesign the mount for more northerly latitudes, but I can’t see that happening before Betelgeuse goes supernova.

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3 Responses to EQ3-2 Mount Tune-Up (Part Two)

  1. John says:

    I have managed to bend the south bolt on my EQ3-2 and it has also come ‘off the cam’.

    It is too bent to be able to unscrew it, so I will need to dismantle in order to get at the bent bolt to attempt to cut it.

    Presumably the black plastic caps (one has the latitude scale on it) on each side of the mount just prise off to reveal nuts/bolt that I can undo to take take the top part of the mount off to gain access to the bent bolt.

    Any words of wisdom or advice greatly appreciated before I bu**er things up even more? 🙂

    • james says:

      Screw the bolt in a little way so it is loose. Say 5mm from the point where it enters the mount, cut off the head of the bolt, then use a hacksaw or something like a Dremel to cut a slot in the cut surface of the bolt. Now use a screwdriver to screw the bolt in until it drops inside and fish it out.

      I’ve never removed the black caps on mine, but were you to ask on the Stargazer’s Lounge you might find someone who has.


      • John says:

        Thanks for the suggestion but I don’t think that’s a goer. The south bolt is almost fully screwed in and it won’t turn more than ¼ turn in either direction .. the end of the bolt fouls on either side of the chamber when so doing.

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