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New EQ-5P Gap between Mount and Tripod

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#1 mike174

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Posted 16 February 2010 - 10:07 PM

Hi,

Friday I received my AT6MEQ which includes the SW EQ-5P.

I noticed when I mount the EQ head to the tripod and tighten down the tripod bolt I have a slight gap at the north-end of the mount. I've hand-tightened as much as I can and closed the gap a little but you can still see light through the gap. I'm thinking that the post that the azimuth adjustment knobs push against might be too tall preventing the eq head and tripod to mate completely. I'm concerned that this might affect stability of the mount if I use a heavier OTA. This is my first GEM coming from a orange C8 and CPC11.

Hope to have a first-light report by the end of the week.

Comments welcome.

Tnx,

Mike

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#2 mike174

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Posted 16 February 2010 - 10:08 PM

Another angle.

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#3 mike174

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Posted 16 February 2010 - 10:13 PM

#3

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#4 mike174

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Posted 16 February 2010 - 10:13 PM

Metal chip.

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#5 Foehammer

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Posted 17 February 2010 - 02:23 AM

The central post's height can be adjusted by loosening its nut and tightening it down a few turns, at least in the CG5 version of this mount it does!

#6 hudson_yak

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Posted 17 February 2010 - 10:11 AM

My SVP came like this (has the same tripod). These are castings and the mating surfaces do not always wind up perfectly flat. The metal is rather soft so deterimine where the high points are (this'll be where the paint rubs off first) and grind them down with a rotary tool, sandpaper, file, etc.

Mike

#7 mike174

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Posted 17 February 2010 - 10:33 AM

I considered that that was the problem and filing would be a solution but I'm not going to do that on a brand-new mount until I hear from SW and the vendor.

Mike

#8 hudson_yak

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Posted 17 February 2010 - 11:51 AM

Ok, good luck. Considering these are inexpensive mass-produced items it's quite likely they all have this problem to at least some degree. They are counting on most buyers to not notice. With that in mind it made the most sense to me to fix the one I had.

As to stability, your concern is well-founded, I could detect rocking motion between the parts even when firmly tightened down, until I ground the high spots away.

Mike

#9 Eddgie

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Posted 17 February 2010 - 12:21 PM

Did you try to remove the azimuth adjusting post from the hub to see if the trunion assembly now sits flat against the hub?

Are you sure that the central rod is threaded FULLY into the bottom of the hub? I have not owned this particular mount, but typically, the rod is threaded at the end, but then there is a gap. This threaded end must be FULLY inside the hub so that the rod will dangle freely under the hub. If you do not have it fully in and the threads in the hub are still engaged when the rod engages the base of the trunion, it will cause this problem.

The fix is to remove the head assembly and continue turning the central rod until all of the treading passes though the hub. Now, put the trunion back on and thread the rod into the trunion.

Regards.

#10 Eddgie

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Posted 17 February 2010 - 01:06 PM

After looking again at your picture, it seems to me that the problem was that the treaded rod was not fully in the top of the hub. When you tightened it, the pressure caused the part of the threading on the rod that was still engaged with the hub to break off.

At least that is the way it lookes to me.

Again, the threaded part of the rod must be COMPLETLY clear of the threads in the hub BEFORE you put the head on. If they are engaged in the base when you tighten the knob, you get what you got.... Top doesn't fit flat and possible to pull threads out of the hub casting.

Regards.

#11 hudson_yak

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Posted 17 February 2010 - 01:36 PM

That's a good thought on how that chip was created. With the SVP this is pretty foolproof because the gap between mount head and hub is wider than the length of the threaded region at the end of the rod, so it can't bridge between the two pieces.

Assuming the rod was eventually tightened enough such that the rod sleeve underneath the hub was making contact, I'd say flatness of the castings is still suspect as to the real problem.

With mine the area I had to grind down was directly behind the azimuth pin, on the underside of the head itself. Before that was done it fit just like the top picture.

Mike

#12 mike174

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Posted 17 February 2010 - 03:28 PM

Hi,

The threads are completely clear of the hub because there is space when I push the threaded rod up from underneath.

The chip was like that out of the box.

The azimuth post is integral to the tripod and can't be removed.

Maybe the thick paint is interfering?

Mike

Az post:

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#13 mike174

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Posted 17 February 2010 - 03:32 PM

Side of post showing mark from az knob bolt on az post.

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#14 Eddgie

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Posted 17 February 2010 - 03:51 PM

Ok. Did you check to see if there was any flashing or something in the well where the azimuth post goes into the bottom of the trunion casting?

Did you remove the the central rod to see if the head sat flush without it?

If you have done all of that and it still goes on crooked, then it must be crooked.

Maybe you will have to (as one other post said) file it down or something.

Oh, well. We tried...

#15 groz

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Posted 18 February 2010 - 11:37 AM

Looks to me like the alt/az adjustment may have been to tight when you attached the head to the tripod, and therefore couldn't slip all the way down around the post. Did you loosen off the alt/az adjustment first?

#16 mike174

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Posted 18 February 2010 - 04:24 PM

Yes. I made sure both azimuth knobs were out of the way. I'm going to attempt first-light tonite.

#17 mike174

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Posted 18 February 2010 - 04:33 PM

I tried all that. The gap is minimal with extra hand tightening. Will attempt first light tonite after I master balancing the AT6M on my first GEM.

Ok. Did you check to see if there was any flashing or something in the well where the azimuth post goes into the bottom of the trunion casting?

Did you remove the the central rod to see if the head sat flush without it?

If you have done all of that and it still goes on crooked, then it must be crooked.

Maybe you will have to (as one other post said) file it down or something.

Oh, well. We tried...








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