Pier idea

[bugeater]

Given how expensive getting piers made seems to be, one option I've thought of is ordering some pipe cut to length and making it myself. The following works out at about $110 and I can pick up locally on a Saturday.

Flat Bar (200 x 10) Length: 200mmx2
Pipe Medium (150NB Med Blk (165.1 OD x 4.8)) Length: 1400mm

Can anyone see any issues with using this?

I'd weld a piece of the flat bar on the top and embed the pier about 500 mm into the foundation concrete block. As far as the adapter for the AZ-EQ6, I just thought I'd re-purpose one of the Skywatcher pier extensions.

I'd have to buy a cheap arc welder + accessories, but they aren't too expensive (Aldi is even selling them next week :lol:)

I'd prefer a bit larger diameter pipe, but that seems to be the largest the vendor has listed (though I might ask if anything else is available). Still, I think it should be pretty stable anyway, especially if embedded in the concrete. It would be pain to remove if I ever wanted to upgrade (especially since an observatory would be built around it), but I guess an angle grinder should be able to remove it eventually.

[Somnium]

how much experience do you welding? welding is an art and can be extremely tricky to do it well. after getting back my pier from Phil at pegasus piers i am glad i had someone who knows what they are doing tackling it.

https://www.facebook.com/pegasuspiers/photos/pcb.449792408561792/449792365228463/?type=3&theater

but if you are up for the DIY challenge then i would love to see the results :)

[bugeater]

I have no idea about welding. But then that's part of the fun really isn't it? Learn a new skill, save some money and get a functional product in the end. But I'd rather not go to all the effort and discover I've wasted my time and should have just ordered one from Phil.

[mswhin63]

I subscribed to welding tips and tricks. Managed to weld my pier after getting a few tips. Started out messy but ended up quite strong and learn't a lot in the process.

https://www.youtube.com/user/weldingtipsandtricks/featured

[Somnium]

i am all for learning a new skill and am up for a diy project. i think the size of the pipe should be okay, mine is 220 but it is probably holding a lot more weight than yours but it is as solid as a rock. have you worked out the connections from the pier to the pier extension to the mount? i am not sure if you still need access under the pier extension, i haven't used one before. if you are giving this a go, i suggest lots of practice before working on the pier itself. sounds like a fun project and a permanent pier is a great asset to have

[bugeater]

Cool. Thanks for the link. I'll definitely need some practice before I try to weld in anger :P



I've got to work out how to join the pier extension. I did find a manual and it looks like the adapter plate bolts to the bottom of the mount. This slides into a tube and is held in place by screws around the sides. This then gets bolted on the tripod from below. If I knew the inside diameter of the pier extension tube, this could maybe be replicated on the permanent pier.
Here's the manual: http://www.opticalvision.co.uk/documents/168.pdf

[AlexN]

No matter how you choose to proceed, ensure you have a method of levelling the mount adapter. Your best bet is to weld a flat square plate to the top of your pier with a long levelling bolt in each corner and another flat plate on top of that. Then you can easily make sure everything is dead level. Then you have an easy flat surface to attach the mount to, and with it dead level you make achieving a perfect polar alignment much easier.

[bugeater]

I'm not convinced of the benefit of the rat cage. Adds complexity and you can still polar align regardless. If I do go down this route I will try to get it close when embedding it in the concrete.

[ZeroID]

I know the 'rat cage' is not a best solution but as long as the support studs are big enough and quite short to reduce any flexure then they are still the easiest to manufacture and despite your best endeavours it is not easy to get a pier dead plumb perpendicular. Not to mention ensuring the top plate doesn't warp slightly during welding and need some amount of 'adjustment' to level.
If it is just out of level Nth to Sth then the DEC adjustment can fix it but any East to West tilt is not so easily remedied. I like my pier top to be as level and as accurate as I can get it, just reduces any other complications.

[Merlin66]

I have the Skywatcher 200mm extension bolted to the top of my pier, then the NEQ6 head.
I think the tube is 3 1/2" (100mm OD) schedule 40 (5.7mm wall) steel pipe. with the interior weld seam removed.

[bugeater]

So I've progressed with this idea. Basically $65 in steel for a 800 mm tall pier plus $89 for the Skywatcher pier extension. The actual tube for the pier extension seems to have the same inner diameter as medium 90 NB pipe, so my plan is to weld a bit of that on the top of the pier and drill three holes in it (ive got some this pipe on order).

I've not actually welded the bits together, but have been practising with my new welder with scrap the steelyard gave me. My welds weren't great to start with, but they are improving a lot with practise and aren't half bad now. Lets hope it all comes together.

[jenchris]

Get someone to critique your welds.
It's easy to get a weld that looks ok and has no penetration.
I don't want you to lose a decent bit of glass or a camera for the sake of a dry weld.

[bugeater]

I haven't started welding my pier yet, but I've been getting a lot of practice doing fillet welds on other bits of metal and are getting the hang of it. I also ordered a short piece of 90NB medium pipe to see if that would fit the Skywatcher pier extension. Once the inner weld seam is removed, it fits! So I'll be welding that to the top of the pier.

Also had guys in today to remove a dead tree right in the best spot in my garden for an observatory. So things are progressing slowly but surely. Main thing I'm dreading is digging the hole for the concrete block - our "soil" is actually rock hard clay.

[AndrewJ]

Gday Marty

Once you get to the hard clay
Just tip a bucket of water in the bottom and leave it for 1/2 hr or so.
Then dig out the soft clay at the bottom and repeat
Slow, but much easier than hitting through the dry clay.

Andrew

[dimithri86]

Feel free to PM me about welding, I did my welding license at tafe a few years ago.

[bugeater]

I have bought a big crowbar for breaking up the clay, which does work, but it's hard work. To test it out, I dug a smallish hole and then out of interest filled it with water. It took about three weeks to dry out! But I will use your idea, but be careful about the amount of water I use!



Thanks for the offer. I'll drop you a line if I have any questions. I've found the welding thing quite fun and are now looking for other things I could make that are useful around the house. I'm actually making a little footstool for my son to reach the sink, out of 25mm x 25mm square tubing. It's tricky to work with, since it's easy to blow through the thin metal with an arc welder, but I'm getting there. I'd actually like to have a go at TIG, since my box can do lift-TIG, but argon is not cheap to access just for a play.

[el_draco]

DO NOT PUT A RAT CAGE ON YOUR PIER. Stupid damn things that negate the structural rigidity of the metal below it. IMHO ;)

[ZeroID]

So how do you do a fine tweaking for level and alignment ?

Believe it or not my rat cage is laminated plywood, about 45 mm thick. epoxied and screwed layers with 4 x M12 threaded rods. Routed out 200 mm disks of 17mm ply. Sealed with marine epoxy varnish. There is only about 75mm between the top and bottom plates. Extremely rigid, hasn't moved an iota in years.

Also very easy to make .. :thumbsup:

[el_draco]

Mounts come with Alt and Azimuth adjustment. Use them. Why on earth would you spend a bomb making a rigid pier and then hang a moving mass on 4 flexible bolts????

[ZeroID]

If the pier plate is not level and the mount is mounted directly your alignment is affected if you have to adjust the AZ point. It will eg rise up E & W if the plate is slightly tilted south and you need to turn the mount head. Probably not too noticeable if you get it very close to right but it is there.

[mswhin63]

I created a hole in my pier cylinder as small as possible that allows me to get a spanner in.

I am going to design and build another unit that will hopefully stop the need to get underneath altogether.

https://goo.gl/photos/K8XVvWAxMsCMp6ui6
The picture is not clear on the hole I created. I never took one in that direction but you should be able to see the hole cut only just.

[bugeater]

I'm not building in a leveling mechanism. It's not required. Being level will help with drift alignment, but even then, I still don't see the point of building a function into a pier that adds a small convenience, but could undermine the pier's actual function.

My plans are progressing. I've ordered the pool pump shed, a tree in the way has been removed, I've chosen the spot, have identified true south (using solar noon) and have broken ground. I think the ground might break me though - it's rock hard and I can't do much in this heat.

[bugeater]

The pier foundation is poured and I've been curing it for the last few days. Took 19 bags of concrete to fill it up. The actual mixing and pouring wasn't too hard. It was the hauling all the bags up the hill that was tough.

I've also received my Absco shed and have assembled each of the panels. I don't think I'd buy their products as a preference in future. What incredibly poor manufacturing. Virtually none of the holes line up, instructions are quite unclear in places and they've provided incorrect parts in places. For example, they say you can bolt the hinges in, but the bolts/screws provided don't recess properly into the hinges, so the hinge can't close fully. It means the frame warps when you close the door. Plus they provide a big bag of bolts and nuts, but the nuts are too large! It's really quite pathetic actually. But I should still be able to get it all together with a bit of messing around.

[bugeater]

It continues to progress. The base is pretty much done except for cutting the right sized hole for the pier hatch. Next I just need to dismantle the shed, haul it up the hill and reassemble on the platform. Also need to trim back the tree next to it, but its been providing welcome shade while I've been working.

You can see from the pictures just how sloped the land is. The second photo is from the optimal place to put an observatory at the highest level of the block, but I'm saving that spot for now. Plus it will be harder to build on.

[bugeater]

Well the observatory is mostly complete. Really just have to seal any residual gaps and probably paint the outside to seal the yellow tongue that will be exposed to the elements.

I can actually park the scope upright with the roof shut, but it just touches the roof. So I'll park slightly offset to one side. Given I made the pier myself it's not too expensive to make another one (about $70 in steel), if I want one taller or shorter, though it takes a fair bit of time.

As I mentioned in the other thread, the double hinges I made for the roof seem to work quite well.