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Permanent Pier and Wedge question

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#1 nitegeezer

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Posted 16 April 2013 - 12:09 PM

I have an LX200 and am getting more serious about astrophotography. I know many have deforked their OTAs and converted to a GEM, but with the outreach I do I want to keep my scope in Alt/Az for the flexibility.

If I were to pour a concrete pier in my yard and mounted my wedge on it, would it be repeatable enough that I could just add my scope and be ready to go? If I could save the time I spend getting the wedge aligned, this would be great, but if I have to re-tune anyway I would just stick with the tripod. My instinct is that this would save me a lot of time, I don't think there is that much slop in the bolts, but does anybody want to share their experience with this?

#2 tommax

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Posted 16 April 2013 - 01:20 PM

I would be curious to know this as well...

#3 jrcrilly

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Posted 16 April 2013 - 01:25 PM

I haven't done as you describe, but I have used a Superwedge. The issues about which folks complain aren't alignment stability but the difficulty in getting it precisely aligned with the available adjustments. I'd think it would hold just fine between uses, so long as the pier doesn't shift.

#4 Starman27

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Posted 16 April 2013 - 01:29 PM

It would save you a lot of time. Once you have properly aligned the scope on the wedge, you won.t have to do it again, unless the pier shifts significantly. All of my scopes are pier mounted. Many clubs have piers with wedges for the use of their members.

#5 nitegeezer

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Posted 16 April 2013 - 02:25 PM

It is neat that some clubs have these for their members. Are the fork mount bases common so one wedge can be used for multiple scopes, or do these have to be identified for use by a brand and maybe even a family model?

In building a pier I have a tractor mounted auger that can make a 3 foot deep hole which would hold a 12" sonotube concrete form. Would this be sufficient or do most piers actually have a buried footing?

I think I feel another project being added to my to do list!!

#6 LoveChina61

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Posted 16 April 2013 - 07:39 PM

Most people suggest a 3x3x3 foot cement footing. You can get away with less if the soil is solid where you are located (e.g.clay). The 12" diameter sinotube on top of that will be plenty sturdy.

Many have complained that adjusting the Superwedge is a pain as there is a lot of "slop" (freeplay) in the adjusters. However, you only need to do it one time so it is definitely worth the hassle. The trick is to somewhat tighten down all the bolts that anchor the wedge to the pier plates. Tighten them down a bit more firmly than hand-tight, and then use the wedge's own adjustment bolts after that. That way you eliminate a lot of the slop that takes place while making polar alignment adjustments. When the wedge is polar aligned well, then you can go back and tighten down the anchor bolts all the way. You should only have to make very slight re-adjustments once or twice per year after.

You might want to look at how I did my homemade pier plates for the Superwedge. It saved me a lot of money and was also rather fun to do :) . You can see my post about halfway down the page HERE .

#7 tim57064

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Posted 16 April 2013 - 07:43 PM

It is neat that some clubs have these for their members. Are the fork mount bases common so one wedge can be used for multiple scopes, or do these have to be identified for use by a brand and maybe even a family model?

In building a pier I have a tractor mounted auger that can make a 3 foot deep hole which would hold a 12" sonotube concrete form. Would this be sufficient or do most piers actually have a buried footing?

I think I feel another project being added to my to do list!!

Your pier depth of course would depend on what part of the country you live in. For the northern climates as where I live,South Dakota, it is best to have your pier depth to be a minimum of 42" even deeper would be better as the frost level can change slightly from year to year. I put all my pier depths at 48 inches to be safe. Do not think you would have to worry about shifting at that depth then. Tim

#8 nitegeezer

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Posted 16 April 2013 - 11:00 PM

LC61, I was afraid someone was going to tell me I needed a footing. Using a tractor auger sounded too easy, but it sure would have been nice. Our soil here is not that solid so I guess that would be the prudent thing to do !@#$%^&*!!

On previewing the post I can't stop laughing. I just held down the shift key and hit several numbers to give me characters that would imply me swearing. I guess they actually meant something and I think it is too cool to change!!

Tim, while I do not have winters quite as bad as yours, I do have to worry about frostline. The local building code requires footings to be buried at least 2 feet, and I was hoping that an auger to 3 feet would be good enough. If I am going to the trouble of digging a footing in, I might as well go to 4 feet also. My poor old back is complaining already!!

Now for the ugly question for both of you. Before I do something that will bite me hard later I want to run one past you. I am considering making two sheet metal plates that have the exact hole pattern as my wedge. I would then take all-thread and lock the two plates about 12" apart. I would take one of the plates and bury it about 8" into the concrete. When the concrete was dry, I would take the top plate off and replace it with my wedge. I know this would take careful planning so I could get a good alignment but what do you think of the idea?

#9 ldesign1

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Posted 16 April 2013 - 11:58 PM

I did not create a footing for my pear. I drilled a 54" deep hole. Poured about 3 inches of gravel at the bottom of the hole. Stuck a 12" by 4' long Sono-Tube with four 4' long rebars in the center. Poured the concrete until almost full and then added another 4' Sono-Tube for the above ground part of the pier with more rebar for reinforcement.

I have heavy clay soil in my yard so there's no sinking or shifting of my pier in the ten years I've had it up.

#10 LoveChina61

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Posted 17 April 2013 - 10:35 AM

Concerning your idea of using the two sheet metal plates to bury your pier plate bolts firmly in the top of the Sonotube cement, that's about how I did it too. I used two pieces of 1/2" thick plywood and bolted them firmly about 4" apart. I did not bury the wood itself, but I used the plywood to hold my long "L-shaped" bolts securely aligned so that they would remain straight while I buried them deep into the Sonotube. The bottom of the "L" dried firmly into the cement and the straight threaded upper part of the bolts stick straight up out of the top of the Sonotube.

The two pieces of plywood helped me to keep the bolts perfectly aligned during the whole process. I took the plywood off after everything was dry.

Good luck. It starts to get exciting from here on out!

#11 nitegeezer

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Posted 17 April 2013 - 10:54 AM

I guess my question is more about the top adapter plate that I see on the piers. If I can hold tolerances and alignment close enough, I am considering having no adapter plate and have the bolts in the concrete go directly to the wedge. I would have top and bottom nuts so I could level the wedge which is my understanding of having an adapter plate. I would think that this would reduce any vibration but I have never seen a picture of a wedge mounted directly to the pier. Is there something I am missing???

#12 tim57064

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Posted 17 April 2013 - 11:19 AM

LC61, I was afraid someone was going to tell me I needed a footing. Using a tractor auger sounded too easy, but it sure would have been nice. Our soil here is not that solid so I guess that would be the prudent thing to do !@#$%^&*!!

On previewing the post I can't stop laughing. I just held down the shift key and hit several numbers to give me characters that would imply me swearing. I guess they actually meant something and I think it is too cool to change!!

Tim, while I do not have winters quite as bad as yours, I do have to worry about frostline. The local building code requires footings to be buried at least 2 feet, and I was hoping that an auger to 3 feet would be good enough. If I am going to the trouble of digging a footing in, I might as well go to 4 feet also. My poor old back is complaining already!!

Now for the ugly question for both of you. Before I do something that will bite me hard later I want to run one past you. I am considering making two sheet metal plates that have the exact hole pattern as my wedge. I would then take all-thread and lock the two plates about 12" apart. I would take one of the plates and bury it about 8" into the concrete. When the concrete was dry, I would take the top plate off and replace it with my wedge. I know this would take careful planning so I could get a good alignment but what do you think of the idea?

As far as your depth goes, the deeper the better.As for digging it, you can save your back and rent a small walk behind backhoe to save your back. A footing would be advised then if you have an issue with the soil in your area. I have a lot of clay here so that is why I held off on a wide footing.
As far as the way you are going to align the bolts for attaching it to your scope,you have chosen a good way to do it, except I do not think you need to bury a plate into the concrete. Steel inside the concrete will rust and cause a premature degradation of the concrete,expand and break apart. If you have a way to hold the bolts in place while the concrete sets up and dries,that would be good enough.Just make sure that the bolts are embedded well into the concrete. Go with the longest bolts you can find and if it will be outside in the weather and not under the protection of an observatory of some type,I would go with Stainless steel as Galvanized will tend to rust after a period of time. Stainless is a bit more expensive yet well worth it when you consider how long you will have that pier.Oh,also make sure you use a minimum of 1/2" diameter bolts. Tim

#13 nitegeezer

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Posted 17 April 2013 - 11:59 AM

I like the small back hoe idea, the problem is I am over an hour away for any rental shop, two hours round trip to get it and two hours round trip to take it back. I think I could hand dig it in that time and then I just get to complain about my sore back!!

If I went with an adapter plate I would use all 1/2" bolts. If I connect directly to wedge the center hole is 1/2" but the three perimeter holes are all 5/16". Would that smaller size concern you?

#14 tim57064

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Posted 17 April 2013 - 12:15 PM

I like the small back hoe idea, the problem is I am over an hour away for any rental shop, two hours round trip to get it and two hours round trip to take it back. I think I could hand dig it in that time and then I just get to complain about my sore back!!

If I went with an adapter plate I would use all 1/2" bolts. If I connect directly to wedge the center hole is 1/2" but the three perimeter holes are all 5/16". Would that smaller size concern you?

If the holes you have to attach the plate to the concrete are 5/16" then you can enlarge the holes if all they are for is attaching to the concrete. The larger the bolt,the better the connection and less chance of vibration transferring to the scope. My opinion anyway.
If you do not have to dig through clay,as I do, then hopefully it will be a little easier.Still a lot of work though.Do a little at a time and you should be okay. Tim

#15 nitegeezer

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Posted 17 April 2013 - 07:05 PM

It looks like I better think this one through a bit more, errors in concrete are not easily corrected.

I do not want to enlarge the holes in my wedge as I want the option of going back to the tripod. I was thinking that the additional vibration of the smaller bolts would be countered by not having that intermediate plate. At least I don't need a decision tonight, I do have time to think about it for a while.

As far as the digging here, I am complaining more than I should. The clay layer is probably down about 5', and the stuff above it is more of a sandy dirt. As long as it is not totally dry, it digs pretty reasonably.

I appreciate your input, I will keep you posted as I go.

#16 tim57064

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Posted 18 April 2013 - 08:00 AM

It looks like I better think this one through a bit more, errors in concrete are not easily corrected.

I do not want to enlarge the holes in my wedge as I want the option of going back to the tripod. I was thinking that the additional vibration of the smaller bolts would be countered by not having that intermediate plate. At least I don't need a decision tonight, I do have time to think about it for a while.

As far as the digging here, I am complaining more than I should. The clay layer is probably down about 5', and the stuff above it is more of a sandy dirt. As long as it is not totally dry, it digs pretty reasonably.

I appreciate your input, I will keep you posted as I go.

Maybe I had misunderstood what you had said about how you would attach the wedge to the pier. What I am saying is,have a plate attached to the pier using 1/2' bolts into the concrete. Then attach the wedge to the plate,steel plate,using your bolts.By no way shape of form would I enlarge the holes in your wedge. You just need to make sure you have enough clearance between the concrete pier and the plate so that you can easily put your hand in to allow tightening of the bolts to your wedge. I hope this makes it a little more clear.If the plate is wider than your wedge,then attaching the wedge should clear the obstruction of the mounting bolts. I am doing this with my setup and will work just fine.Just make sure that the bolts attached to the plate are wider than the diameter of your wedge. I made a 1/4" thick steel plate that is 12" in diameter. Sorry if this is a little confusing. Tim

#17 nitegeezer

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Posted 18 April 2013 - 11:13 AM

Tim and I have a discussion going offline in PMs, but just so this thread is useful to others I want to explain my situation a little more.

I do understand what has been mentioned about the whole mounting scheme. My problem is that I have a wedge that is slightly over 11" wide and I would like to use a 12" diameter concrete pier. This combination does not allow me to use a single support plate, I just can't spread the bolts far enough in the concrete. This means I would need to use two plates, and I have seen pictures of others who have done this. The first plate mounts to the pier but is larger so it can spread some bolt holes out beyond the wedge. The second plate bolts to the first plate and the wedge mounts to this plate. I am not happy with a two plate system, so my choices are to either bolt the wedge directly to the pier with no support plate or go with a larger diameter concrete pier so the bolts could be wide enough to miss the wedge and then use a single support plate. The last solution is probably the best, I just do not like having that larger concrete section.

I will post any neat breakthroughs, but if the there are other ideas I am very interested.

#18 Mike7Mak

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Posted 18 April 2013 - 01:36 PM

Rather than bring the concrete all the way up to the wedge, which is a rather unforgiving, unadjustable permanent monolith in the yard, I'd suggest dig and pour a footing block with its surface a couple inches below grade. Set in J-anchor bolts for the base plate of a metal pier.

A metal pier is adjustable by cutting and re-fabricating and is also removeable should you sell out and move. All that needs to be done is hacksaw the J-anchors and cover the base block with dirt.

Something along these lines if you imagine the base of a taller metal pier at ground level.

Attached Files



#19 nitegeezer

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Posted 21 April 2013 - 11:49 PM

I have been thinking of a variety of options, and another one just hit me. Has anyone ever tried a tire full of concrete similar to the old tether ball poles? I was thinking of one for the base and then add a steel pier like Mike has in the post above. Would this be a reasonable solution?

#20 tim57064

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Posted 22 April 2013 - 07:15 AM

I think before I did something like that, I would offer a pizza and beer party to some of my friends to give me a hand in digging the footing and placing a pier.My opinion yet would think it would only be a little better than setting up my tripod. Tim

#21 Kraus

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Posted 22 April 2013 - 03:11 PM


The answer is yes.

I poured a concrete pier in my backyard for my Meade wedge. I aligned it via star drift. When I wanted to obsevere, I just drop the 2080 onto the wedge, insert the eyepiece, connect power and the night was mine. It maintained alignment for many years.

Now I've graduated to a fourteen inch LX-200. Same pier but I use cables from the wedge to cement anchors in the ground because Bertha weighs so much more than a small 8 incher. The wedge isn't really designed for the weight but mounting bolt demensions are the same from the 2080 to the LX-200 base.

Have fun.






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