Slapdash Temporary Pier & Mount

[upahill]

My plans for a decent outdoor obsy and pier have been put on hold for a while, but I wanted something a little more reliable for the winter that didnt take an age to set up (or end up living in the hallway)

My goal is to make this as cheap as possible and as quick as possible. It's not forever and I would rather but the money into the right gear at the right time.

I saw a todmorden pier on here and decided that would be the best approach. Unfortunately under the grass, about 3" down is solid stone, digging isnt going to be an option without getting machinery in and permission. Current plan is 3" of sub-base sand, a 600x600x50 slab, and then 3 concrete blocks for the height. Since its temporary the blocks will be glued together ?

The 'pier' is actually level in the picture, its the ground, fence posts and hills that are wonky.

I had a look at pier adapters and they are quite expensive, eventually ill likely get the Altair one, but as a test I figured I could print one, and if it works - cast it out of a strong resin.

Fingers crossed the print will be finished in an hour or so and I can test the tolerances.

If it goes to plan I'll only need to take out the scope and briefcase with all the hookup cables etc out each time. Ill probably construct something that goes over the mount to keep any rain off but let it breathe, or get a telescope cover if anyone has any reccomendations.

I had planned to drill 5 holes in the top of the block, the spacing is just about right if it sits quare, hence the additional holes for azimuth pegs as north is slightly off axis. Then again its disposable and re-printable so may try out the glue here too and only do the one central hole.

I think in total the pier weighs about 70-80kg which makes it fairly solid and its sat on a flat rock the footprint of a car so fingers crossed.

[JamesF]

If there's solid rock so close to the surface then I see no problem with that.  The rock will (hopefully) not be going anywhere, after all.  Half my house is built on foundations like that.

James

[upahill]

1 minute ago, JamesF said:

If there's solid rock so close to the surface then I see no problem with that.  The rock will (hopefully) not be going anywhere, after all.  Half my house is built on foundations like that.

James

Thats what I figured, i contemplated drilling some bolts into it and then bolting the slab to that - its all a bit of a test really. Needs to be easy to remove without leaving a tonne of concrete in the ground, and slightly more convenient than a tripod.

[upahill]

Printed OK and fits good. There is some play which I expected as I oversized the central dip and tapered the verticals incase I do create a mold for resin.

It's suprisingly strong and should handle the mount ok as it is though, clamped through the block with a large washer.

4x M10 bolts to hold it in place if I don't go down the glue route, the azimuth pegs will be either a bit of metal cut to fit or just a metal pin - not sure on the implication if any of having a round azimuth peg - the one on the tripod head is square. They are 8.6mm which I did so I can tap them out to M10 if I go with resin.

[sloz1664]

10mm bolts will ensure the plate goes nowhere. It doesn't need to be level, polar alignment takes care of that and a round pin will be fine for the azimuth peg. I used a 12mm hardened dowel when I set up my old EQ6 pro.

Great temporary pier & mount btw

Steve

Edited September 22, 2018 by sloz1664

[upahill]

Well the glue is 'curing' so hopefully it will be a bit more rigid than it feels at the moment.

Im going to need a longer M12? nut for the main bolt, and a metal spreader plate for inside the owls nest. I am amazed at just how crumbly these blocks are - after drilling a hole (suprisingly easy) its just pretty much crumbling around the edges.

3D printed adapter isnt strong enough to hold a azimuth peg unless I print again at 100% infill - but given how crumbly the blocks are im half tempted to do something completely different at the top, I have some 8mm steel plate somewhere I could cut to the same size as the top and this would give me something solid to work from, then bolt an adapter to that.

Is an azimuth peg even necessary if its staying set up? A good polar align and clamp down should be enough to stop it from moving around.

[Stub Mandrel]

On 22/09/2018 at 01:36, upahill said:

about 3" down is solid stone

Surely that's ideal?

[upahill]

2 minutes ago, Stub Mandrel said:

Surely that's ideal?

I think so. The glue has set today and the pier is fairly solid - well within my requirements anyway. I was stood where the mount is now and it wasnt shifting.

I am having a redesign of the pier adapter though, and printing a new one - wasn't happy with it at all.

The pin slots now go all the way through and a chrome rod will be pushed through the pier adapter, stone block and then epoxied in place.

Some of the mass removed to cut down on material as ill be printing with a denser infill.

Some of the cut outs have been shrunk to give a much tighter fit.

I should still be able to cast out of resin if I get the time, will just block off the pin holes and drill/tap the final fitting for the actual eq6 peg.

Have ordered the hardware for mounting everything so that will hopefully get here on Tuesday and I can get back to imaging. Full moon tonight and its like daylight out there so happy being indoors ?

[upahill]

Another print failure, thought I would try and recover by printing the second part anyway and gluing them together but frankly its not going to happen or look right so trying again.

Argh!

[Peter Drew]

A pimped version of the "Todmorden" pier for those who don't like its "nude" look.     ?

[upahill]

Ooh thats a nice idea... looks a little better.

[Dr_Ju_ju]

That looks like your model isn't 'whole', in that you have a one layer gap between top and bottom sections.

[upahill]

1 minute ago, Dr_Ju_ju said:

That looks like your model isn't 'whole', in that you have a one layer gap between top and bottom sections.

Haha yeah, its 1 layer of gorilla glue now

[upahill]

Well its as done as its going to be for a while.

Bolts arrived today - the 4 bolts to hold the adapter in place were supposed to be fully threaded but got sent shoulder bolts instead - luckily had a few extra washers to make up the difference.

My 3D printed peg idea probably would have worked - its rock solid but too short - doh! I really dont think it will be needed though.

Mount bolt is perfect, used a 2" spreader washer underneath to tighten up against.

Just need to clean up now, set up the rest of the gear for a polar alignment tonight - and maybe mow the lawn! Next project is rebuilding the dob in the background - tried using it last night and its just dreadful, but thats for another thread.

 

Edited September 25, 2018 by upahill

[upahill]

Thought I would post an update to this....

I'll preface by saying that 1) yes a proper pier would be better/safer/sturdier/etc and 2) If I had the money/time/freedom I would redo this in a heartbeat but here are my thoughts after a few months of actually using the pier.

Firstly, its pretty solid, its a patio slab on 2 inches of sand with no mechanical fixing to the ground, the building blocks are not bolted together but simply gorilla glued. This is madness, but it works. It wont budge and I have no fear of knocking it over.

Secondly I took some flack in the 3D printed astro group on facebook for risking my equipment on a PLA printed pier adapter. The consensus there was that it would deteriorate, become brittle and my scope and mount would come tumbling down. I understand the logic behind that but again the reality is that it does what it is supposed to. There is no apparent deterioration of the plastic, no creaking, cracking or any other untoward noises. I'm not saying it will last forever, and I should make a metal adapter instead but for now im confident my gear isnt going anywhere.

Thirdly, my guiding seems pretty reasonable, averaging about 0.25 total error. Some of this is down to the mount needing a tune too. But its better than I get on the heavy duty tripod so im happy with that.

Fourthly, Polar alignment is maintaining very well, the mount stays outside for weeks on end under cover and is always ready. I have polar aligned once when I built the pier and once when I returned from SGL2018 - doing it again tonight to test revealed no change of more than a few seconds.

Fifthly, It could do with some masonry paint, when it rains the concrete does absorb the moisture and it looks ugly. I cover the pier and mount in a heavy duty cover and buckle it to the pier which seems to do fine.

Whats Next

Until I can build an obsy, the plan is to keep using this setup - but I do want to make it a little better so will clad the pier in something and weatherproof it. Im also going to lay some concrete around the slab to add a little bit of protection from the soil eroding away around the edges.  I am also going to build a frame around the pier about halfway up that a  box can sit on top of and clamp down onto. This will mean at 4am I can just put a box on and go to bed and worry about packing up in the morning. I also may consider adding some outdoor sockets to the pier (although im considering a 12v and Cat5 run out to the pier instead.

If you are in a tight spot financially but want a pier I just dont think you can do better than this for £50ish. If you use the adapter off your tripod instead you can avoid the 3d printing too.

I am halfway through designing this.... and when I build it there is a strong chance I will use this style of pier again.

[upahill]

6 Months on and the pier and mount are still perfectly stable. They both stayed outside during the autumn/winter/spring bagged over but fully exposed to the weather of the valley including snow, gale force winds etc.

Each time I have set up the polar alignment has been pretty much spot on, but the main reason I left it all setup was to test the 3d printed adapter. Despite the ribbing I got on FB the PLA has held up fine, no deterioration or melting, no mounts on the floor.

Given that there isnt even bolts between any of the blocks either im reasonablly impressed by that and will consider it a success.

I looked at covers for the whole setup that I can throw over during a session should rain start etc. Ended up picking up a £23 egg chair cover off amazon that will do the job for now.

The obsy plan is on the backburner for the moment so this setup is going to have to last me through the summer and probably the winter again.

PS: The extension isn't live  😛 🌧️

As there isnt any astro dark at the moment (or clear skies) im considering now as the perfect time to rebuild and tune up the EQ6. It's looking a little tired and could do with some new bearings and go faster stripes.

[Stub Mandrel]

6 hours ago, upahill said:

the main reason I left it all setup was to test the 3d printed adapter. Despite the ribbing I got on FB the PLA has held up fine

My meteor detection aerial, held together by black PLA parts, is intact after a year exposed to the elements, right up in the air. Looks as good as new, fingers crossed...

[Skipper Billy]

I love simple solutions that work well.

If you are worried about the plate a cheap alternative is to use a car brake disc - from memory I think its a Skoda Octavia front disc that the right size but check first!

 

[upahill]

22 minutes ago, Skipper Billy said:

I love simple solutions that work well.

If you are worried about the plate a cheap alternative is to use a car brake disc - from memory I think its a Skoda Octavia front disc that the right size but check first!

 

I had considered this, there is a welder near me with some 8" box section laying around in his yard so was considering asking him to make me a pier - a brake disc would be a good solution for the top of it for sure.