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Leveling, orienting pier

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#1 FrankG

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Posted 04 August 2021 - 05:49 AM

I have a metal pier on order. Would a simple, two-axis bubble level be sufficient to make sure the top of the pier is level after anchoring in concrete? I plan on using my iPhone to make sure post for CGEM II is pointed north -- is that sufficient?

 

Many Thanks,

 

Frank



#2 james7ca

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Posted 04 August 2021 - 06:12 AM

Don't use the iPhone, the compass in phones isn't very accurate. They can easily be off by 10 to 20 degrees. As for the level, a bubble level should be more that good enough. As for determining true north, you could use an inexpensive orienteering compass as long as you don't have any ferrous (magnetic) objects near to the compass. However, you'll need to offset the reading using your magnetic declination/variation (varies by you location, you can look up that value on the internet).

 

Another method is to plot the shadow of the sun during your local (true) noon (i.e. when the sun is due south). I think there are discussions about how to do the latter here on CN.


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#3 kathyastro

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Posted 04 August 2021 - 06:27 AM

Go out at night and find Polaris.  That will tell you which direction is north from your pier site.  Put a stake in the ground, or tie a ribbon to vegetation to indicate that direction.  That will get your pier well within the adjustment range of any mount.

 

Level isn't super critical, so a bubble level will be fine.


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#4 blazek

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Posted 04 August 2021 - 07:16 AM

I oriented my pier by shadow at true noon. It was spot on , not  much of adjustment was required. For leveling, as mentioned above, any kind spirit level,  including bubble,  will do . 


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#5 John Fitzgerald

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Posted 04 August 2021 - 08:20 AM

Ordinarily,  the pier itself is not set in concrete.  The pier is set on j-bolts that are set into the concrete when it is poured.  Anchoring a metal pier itself in concrete is not a good idea.



#6 FrankG

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Posted 04 August 2021 - 09:07 AM

Ordinarily,  the pier itself is not set in concrete.  The pier is set on j-bolts that are set into the concrete when it is poured.  Anchoring a metal pier itself in concrete is not a good idea.

Yes, it will be set on bolts into the wet concrete.



#7 macdonjh

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Posted 04 August 2021 - 12:10 PM

+4

 

A bubble level will get you plenty close to plumb.  Whatever error is left will be easily accommodated when you do your polar alignment.  Same with finding north: either a compass or using a shadow at noon.  I don't know why, but my compass gets confused by my aluminum mount.  Perhaps it's the stainless shafts (still iron in there, even if the bulk metal isn't magnetic).  Anyway, when using a compass to point my mount north, I stand three feet away or so and sight along the mount's housing.


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#8 FrankG

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Posted 20 August 2021 - 01:39 PM

Thanks all for your suggestions. I used true high noon by the sun and purchased a good compass and the two are in agreement (accounting for magnetic declination). For the heck of it, I used the iPhone app and it was dead-on as well. It's an old iPhone 8 but it agreed perfectly with the sun and compass results. FWIW. May not work with all phones or in all locations but it appears to work here, today at least.

Thanks Again

Frank


Edited by FrankG, 20 August 2021 - 01:40 PM.



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