Looking for a 6 to 8 inch steel pipe for a pier

Hi Joe,
Welcome to the boards!

Constructing a steel pier can be done significantly cheaper. I certainly spent less than half what you paid and felt I paid alot!

Initially, I got a steel pier made up with a plate welded top and bottom. The pier was 250 x 250 mm square section with a 12mm thick plate welded top and bottom. Extremely sturdy. Here's a photo:


This was bolted to a foundation under the floor of the observatory and kept separate from the floor to ensure vibrations didn't transmit into the pier. I bolted it to allow for the possibility of removing it sometime in the future. Burying it in concrete is also a very stable solution, but a very permanent one too.

However, I changed scope and mount and needed to raise the height of the pier. I decided to extend it with a round pier with a round plate welded top and bottom. This gets it raised up to the level I want. The advantage of having it round was that corners don't exist near the top of the pier and so minimise the risk of the scope/mount hitting the pier when slewing.

The advantage of having the pier extended was that I could precisely level the top plate of the extension by the addition of spacers in between the original pier and the extension.

If this method isn't employed, it will be very difficult to get the top of the pier level and will usually require a plate suspended above the pier and connected to the pier with a 3 to 4 bolts to allow for precise levelling.
This is the original pier with the suspended plate held above it to allow for precise levelling of the scope:

In this case, I had the pier low as I wanted to allow for future upgrades. Problem though was that for the scope I had at the time, the suspended plate was very high above the pier, leaving it more susceptible to vibration.

This here is the pier extended:


This is a far more stable configuration and works a treat - rock solid. I've used this with a Gemini Observatory + mount with 36kg of counterweights, a Meade 12" SCT and a 3" apo piggybacked on top. At no stage was the strength or stability of the pier an issue.


The benefits of building the column in two pieces are:
1) The lower half could be permanent whilst the top half can be changed depending on what mount/scope you have in the future. Of course, if I ever move house, I could remove the entire pier. However, if I'm just changing the mount & scope, it's very easy to just change the top half of the pier to suit.
2) By not having the plate suspended in the air by a few bolts, it keeps it more rigid.
3) When the two sections of the pier are bolted together, the flanges act as stiffeners thereby increasing rigidity.

If I were doing it all over again, I would have kept the bottom half round also. However, I had no idea at the time that I would end up with the setup I have now. The diameter I selected for the top half is also specifically chosen based on the size of the base of the new mount I have.
Note though that a square section of steel is normally alot cheaper than a round section.

Hope this helps,

Joe,

What I used was a 10" Sewer pipe (Wavin). I got it from a guy here on these boards so I can;t help on where to get some, I did here it is expensive. The pipe is filled with concrete.

See here for some info on how I set up the pier.

webtreatz.com/content/view/43/1/

I read that the pier should be the same distance below ground as it is above. Thats how I did mine and it works well.

Hi All,

When building an observatory there is no need to spend a lot of money on piers. Go to a building site and ask the lads to cut 8ft of gas pipe just remember your pier has to be as deep in the ground as it is above. The builder will have no problem giving you some gas pipe throw him a few quid. I have my pier 4ft above ground and 4ft below plus i have 184lbs of telescope equipment on top of it and it does not budge. The hole project cost 1200 euro

Here is a link it will give you some ideas of how to go about it. This is one we did for a good friend of mine last summer.

I hope to have some images of my own observatory soon.

webtreatz.com/content/view/43/1/

If you have any questions please ask away.

7 replies in just under 2 hours. You'd know it was a rainy night all right.

I really don't want to use concrete if I can get away with it. This is somthing that I'd like to be able to dismantle if I move. Not every house hunter wants a concrete pilar in their garden...

I had thought to put in a concrete foundation a foot or two below ground level & bolt the metal tube to it. That way I could dismantle the tube & back fill the hole if necessary.

Also I've been told that a concrete pier should be done in one pour. I don't know if this is true, but it makes a bit of sense. In my case that would involve getting the concrete pumped in. If it could be reliably done in stages using reinforcing bar it might be a runner (reluctantly). Dave/Carl, what did you do for yours in this regard?

I have to say that I love the 2 stage pier. Very handy if you need to take it apart. Now thats got me wondering about bolting a few of those flanged pipe junctions together.......


Joe

Joe,

What I used was a 10" Sewer pipe (Wavin). I got it from a guy here on these

very ingenious!
I've seen plumbing pipes of all sizes being made into
Dobs, Light blockers, Binocular seats and...piers.

Just go's to show you don't need piles of cash, just a little thinking.

... Also I've been told that a concrete pier should be done in one pour. I don't know if this is true, but it makes a bit of sense. In my case that would involve getting the concrete pumped in. If it could be reliably done in stages using reinforcing bar it might be a runner (reluctantly)....

I encountered all these issues in my two-stage concrete / metal pier construction. It's a rather long thread, but there are lots of pictures (and a bunch of info you'd likely find useful) on CloudyNights:

www.cloudynights.com/ubbthreads/showflat.php?Number=544994

-- Jeff.