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

I'm looking to set my scope up a bit more permanently. I'm fed up dragging it out, polar aligning it & setting up cameras etc. only to see the clouds roll in. I'm using a C9.25 on a wedge.

I wanted to setup a sturdy pier, possibly with a view to upgrading the scope later. With that in mind I thought a steel pipe about 6-8 inches in diameter & about a metre and a bit long on a concrete foundation would do. It would be great if it had a flange on it. Any ideas on where to start looking? I'd go with a concrete pillar, but would like to be able to dismantle it if necessary.

Saw some flanged junctions of about the right size at the back of Chadwicks at the weekend, but no-one knew anything about pipes to match them, so I suspect they were junk.

I'm in Dublin.

Joe

Joe,
from what little experience I have, though I did help out sometime ago in the building of a permanent observatory, 6 to 8 inches in diameter would be surprisingly short for such a could-be heavy instrument. I'd recommend 10 inches filled with sand, or 8 inches filled with cement. Construct your mount seperately, because you will have to ensure that the pipe, once in position, will never move. You'll only be able to ensure it is a vertically straight as possible with no attachments to it with the aid of plumb lines and spirit levels. Once it has set, adding the mount should be second.

There are some guys here that have also constructed pier/pillar mounts, I'm sure they'll add to the conversation with more better advice than I could give any more on.

One thing to bear in mind during your planning phase is to construct the floor as a seperate entitly from the pillar i.e. the 2 should never meet/touch. Ensure your pillar is sunk at least 16 inches below groundlevel (not floor level) into a foundation too.

Welcome to the Boards!

Seanie.

Yes, I've just finished setting up a pro-dome with an isolated floor in work. I got the pier made up. It was 30cm diameter steel pipe with flanges top & bottom & butresses extending from the bottom flange approximately 50 cms up. I thought it was overkill at the time (for a 11 inch scope currently), but that was the advice we got from the engineer. It cost ~1K!

Now I'd be paying for this one personally, so I was hoping to get away with less. Maybe thats wishful thinking. Many pier designs I've seen on the net are circa 8".

Joe

Hi Joe,
I'm based in Limerick so I can be specific about where you can get it , but try looking for a metal works nearby.
I got a 10 inch pillar (an end off cut) and got a welder to weld on 2 square 16" plates, one at both ends, these plates are an inch thick solid steel. The pillar is 5/8 inch thick, so it weighs alot. The bottom plate is secured to concrete using 4 8" rawl bolts, i drilled for 8 but didn't need them all.
I then got those guys to precision drill 4 holes so that I could suspend a third plate above the second plate using thread bars and bolts, I did this so that I didn't have to care about getting the pillar level, I could level the third plate by adjust the bolt heights on the thread bars.
i also have a hole at the bottom of the pillar and at the top where I run all my cables, very neat and trip proof.
I over designed my pillar as I wanted it to be vibration proof and rock solid. Its also well able to carry a much bigger scope then the 12" + wedge currently mounted on it, always think of upgradebility so you only have to do this once.

The secret to getting a good price from an engineering shop is to use off-cuts they have lying around in the yard. I got a 10" pier (about 50" long) with top and bottom plates, gussets, and hot-dipped galvanizing all for less than €500.

(Voss Engineering in Summerhill, Co Meath did mine.)

-- Jeff

here is a pic of the top end of the pillar to show what its about.
Jeff is dead right , use end pieces and you have to get it hot dipped galvonised in our climate or at least get it well coated.

farm2.static.flickr.com/1322/571464694_4701565b7f_b.jpg