Pier Size

[Hemi]

GDay members,

I’ve been reading about pier properties. Diameter, thickness, material.

I had settled on a steel pier, but I’m getting contradictory advice.
Can I have your thoughts on if a steel tube, 140mm diameter, 6mm thick would be suitable for a pier? It will be filled with sand or pebbles, not concrete. And attached to an existing concrete slab with bolts. The top will have a bird cage type setup for an AZEQ6 mount.

I was initially going with 160mm@8mm but the vendor said this smaller tube would be sufficient.

Thanks

Hemi

[doppler (Rick)]

That's about what I have, mine is rectangular though but it works for me. It is filled with fine sand to eliminate acoustic vibrations. I think a lot of people go overboard with their specs. Any sort of pier is a huge improvement over a tripod.
Rick

[Wilso]

I made mine about the same size 150 diameter and 6mm thick which is very sturdy. I would beef up the base plate to maybe 8 or 10mm for bolting to the concrete though. The only difference I cut an access hatch in the side to tighten the mount down.

[lazjen (Chris)]

Your weakest link in the pier set up is going to be the cage on top, so you don't have to go overboard with the tube. It's probably not even worth putting sand/whatever in it either.

Can I ask why you are doing a cage on top?

[Sunfish (Ray)]

My pier is 6mm thick 102 diameter steel bolted to an existing large concrete slab on footings and it seems quite stiff. I have also made 30mm pipe knee braces to half height for a previous installation but found I do not need them.

Rather than the cage, if you can cut a 60 mm hole in a 25mm thick 100x100 aluminium plate ( or three stacked 8mm plates or steel ) and bolt that to a removable 150x150 base plate. You can fit the plate to the HEQ5 mount and bolt down the whole assembly each time to an alignment line etched in the plate. Or swap mounts as I do on another plate.

Just ensure you have a 30mm hole in the middle of the pier top plate to accept the mount bolt head.

If you use a cage, the bolts should be quite beefy, so that their cross section adds up to the same as the material in the mount base.

[Sunfish (Ray)]

The key operated hatch is a great idea.

Originally Posted by Wilso

I made mine about the same size 150 diameter and 6mm thick which is very sturdy. I would beef up the base plate to maybe 8 or 10mm for bolting to the concrete though. The only difference I cut an access hatch in the side to tighten the mount down.

[Hemi]

Thanks everyone,

Lazjen, the reason for the cage is to get the mount level.
The tiled floor is on a gentle incline for draining rain water. I know that there is regular debate about the importance of that, but figured I might as well get the mount level, before adjusting for polar alignment.

I can understand why strict levelling isn't so important for polar alignment, but cant help feeling that it makes a difference for the mounts modelling for GOTO's.

Currently wondering how to attach the AZEQ6 to the top plate in any case. Using a ready made adapter seems the easiest option, unless anyone knows where I could find the drawings for the AZEQ6 base.

Hemi

[traveller (Bo)]

In case you are interested Hemi, here is my pier build from a few years back
http://www.iceinspace.com.au/forum/s...d.php?t=136618
Hope that helps in your planning and design.
thanks
Bo

[Merlin66 (Ken)]

I have the C11 sitting on the NEQ6PRO on a similar pier.
I added the standard 200mm extension to the top, uses a 12 x 1.75mm stud to fix to the top of the pier.
The NEQ6PRO head just fits as usual to the top of the extension.
No cage etc, works very well, no real issues, no drama.

[Hemi]

Thanks again folks,

Bo, the thread you posted was very helpful. The collar (circular top plate with pier extension) would make for a great EP holder!
How have you attached the pier extension onto the top plate...could not work it out. Are there any issue with the pier extension spinning like when its on the tripod. I have the pier extension already so might be the way forward, but without the rat cage it would mean the pier is on a very gentle incline.

Darren how did you do the cut out and lock, do you have any instructions or diagrams I could follow?

Cheers

Hemi

[doppler (Rick)]

You could also put spacers / washers under the pier base plate to level it that way.

[Wilso]

No it’s not a lock, just a home made knob!
I just used a thin cutting disc on the grinder and glued rare earth magnets on the inside corners to hold the hatch in place rather than a hinge.

[traveller (Bo)]

Originally Posted by Hemi

Thanks again folks,

Bo, the thread you posted was very helpful. The collar (circular top plate with pier extension) would make for a great EP holder!
How have you attached the pier extension onto the top plate...could not work it out. Are there any issue with the pier extension spinning like when its on the tripod. I have the pier extension already so might be the way forward, but without the rat cage it would mean the pier is on a very gentle incline.

Darren how did you do the cut out and lock, do you have any instructions or diagrams I could follow?

Cheers

Hemi

Like Rick said, you can ust washers etc to get the extension pillar level.

The attachment is in three sections
1. The 150mm pier adapter is bolted to the pier top plate with 4 M12 bolts and nuts.
2. The extension pillar has two removable plates. The bottom plate (without the star nut) is separated from the pillar tube (undo the 3 M5/M6 hex bolts from the side). It is secured to the pier adapter via the centre M12 bolt. The pillar tube then slides over the top and secured using the M5/M6 hex bolts.
3. The top plate of the extension pillar (with the star nut) is secured to the base of the mount (with the az adjustment bolt). Then the mount head with the attached top plate of the extension tube is lowered into the pillar tube and secured with the 3 M5/M6 hex bolts.

If all works out, the whole unit is very solid and secure, no movement!
Let me know if you want me to take some photos to show you.
Cheers
Bo

[Hemi]

Darren, the magnets are a clever idea. Will do that if I go bird cage free.

Bo, some pics would be helpful, if not too much trouble. Do you need the adapter plate....can you just attach the mount straight to top plate?

Hemi