Pier Caps - leveling facility or not? (more questions)

[russp]

Working with sketchup on the extra decking and the pier and roll off and it's track and reading through the threads I'm getting increasingly confused about pier caps - I thought the threaded rods two plates was to level up the top plate accurately .. but I see references to level not being critical ? Doesn't this affect polar alignment? Was going to get a local metal worker to fabricate a pier and if it's just one plate needed could make it simpler. 

Thanks for any clarity you can provide!

Russ

[ChrisLX200]

Is it essential? No.. your mount already offers the required mechanical adjustment to achieve perfect polar alignment regardless of whether it starts out level or not. However, starting with a level plate means you can make an independant adjustment in Altitude OR Azimuth without one affecting the other - as it would if the mount were not level. Why would that be of benefit? Only for making drift alignments really which is done in two stages - first stage alignes the altitude and the second the azimuth, if one sets the altitude accurately using the drift method and then procedes to adjust the azimuth, if the mount is not perfectly level then tweaking one will also affect the adjustment of the other (slightly). This is hardly a serious problem though, and if you use any other method of polar aligning it won't affect you at all.

 

[Davey-T]

According to our much missed friend Per the 10Micron was better set up level as aiming north and level gave it a solid start for modelling, not sure if it applies to other "modelling" mounts.

A separate mounting plate will give you the option to change it if you change the mount.

Dave 

[Skipper Billy]

Another reason is access to the bolt that holds the mount to the plate. It depends on the make of the mount - I couldnt install or uninstall my mount without two plates - I guess I could have a fixed single plate and a hole in the side of the tube but this way easier for me.

If you do go for the rat cage just make sure you use substantial bolts and  plenty of them - I have seen some with 4 x M8 bolts - flexure guaranteed! I used 8 x M14 - it doesnt move!

 

[D4N]

Mine has the threaded bars cemented into the pier so only one plate required.

 

 

[laser_jock99]

26 minutes ago, Skipper Billy said:

Another reason is access to the bolt that holds the mount to the plate.

 

I used an 'owl hole' drilled into the pier to access the mounting bolt. Handy for routing cables down the pier too!

There is no need for a 'leveling plate' on the pier - but of course the obvious engineering solution is to build the pier so it's level in the first place!

Owl hole in pier tube.

 

Mounting puck that drops in the already leveled pier tube.

 

[russp]

3 minutes ago, laser_jock99 said:

I used an 'owl hole' drilled into the pier to access the mounting bolt. Handy for routing cables down the pier too!

There is no need for a 'leveling plate' on the pier - but of course the obvious engineering solution is to build the pier so it's level in the first place!

Owl hole in pier tube.

 

Mounting puck that drops in the already leveled pier tube

Does that bolt under the puck fix into a plate in the (levelled ) pier tube?  Neat solution

[laser_jock99]

6 minutes ago, russp said:

Does that bolt under the puck fix into a plate in the (levelled ) pier tube?  Neat solution

No- the bolt just fixes the mount to the puck (as it would do on a standard tripod). In the photo it just isn't tightened on yet.

The puck can actualy rotate round in the pier tube if required (crude azimuth adjustment!) - but is normaly locked in place with some M6 socket cap heads taped into the tube.

[michael8554]

D4N - compare your image with Skipper Billy's, and consider shortening your studs !

Michael

[D4N]

12 minutes ago, michael8554 said:

D4N - compare your image with Skipper Billy's, and consider shortening your studs !

Michael

I have considered that but the setup I have on it is just a small frac' so it is all quite overkill anyway.

[Davey-T]

Need access under mine for bolting down.

Dave 

 

[RayD]

3 hours ago, russp said:

Working with sketchup on the extra decking and the pier and roll off and it's track and reading through the threads I'm getting increasingly confused about pier caps - I thought the threaded rods two plates was to level up the top plate accurately .. but I see references to level not being critical ? Doesn't this affect polar alignment? Was going to get a local metal worker to fabricate a pier and if it's just one plate needed could make it simpler. 

Thanks for any clarity you can provide!

Russ

You have an AZ EQ6 mount, so if you are ever likely to use it in AZ mode then my understanding is that a level pier is necessary.  It doesn't matter so much if you are only ever going to use it in EQ mode.

[russp]

12 minutes ago, RayD said:

You have an AZ EQ6 mount, so if you are ever likely to use it in AZ mode then my understanding is that a level pier is necessary.  It doesn't matter so much if you are only ever going to use it in EQ mode.

 Ah thanks, yes, not overly sure why I'd ever want to use it in AZ mode on a permanent pier but as someone said earlier just install the pier level in the first place

[SonnyE]

18 hours ago, russp said:

 Ah thanks, yes, not overly sure why I'd ever want to use it in AZ mode on a permanent pier but as someone said earlier just install the pier level in the first place

Having the base for any mount as level as possible eliminates troubles later on. I use a digital level for my tripod when moving it. I find working for 0.0 degrees easier with it.

If we do each step as accurately as we can, we won't suffer consequences later for being hap-hazard. Accuracy is key.

[ollypenrice]

I don't know about the model-maker situation but piers don't need to be level to allow mounts to be polar aligned. As Chris said, levelling reduces interactions between axes when drift aligning but the effect is very slight. Obviously it does no harm to be level - unless you compromise the stiffness of your pier when you introduce the levelling mechanism, and this is precisely what many pier builders do. We often see massively concrete-embedded piers of great girth ending in three bits of teetering threaded bar. This defeats the object. Better stiff than level.

Olly

 

[russp]

Thanks for all the replies - have worked up my pier in sketchup now and will level it on the holding down bolts the way we do with columns for steel framed buildings prior to grouting it solid - after that it shouldn't go anywhere and it'll be so close it will make no difference. 

 

[Davey-T]

48 minutes ago, ollypenrice said:

I don't know about the model-maker situation

Olly

Video on 10Micron mounts by Per where he mentions levelling at around the 51 minute mark.

Dave

https://www.youtube.com/watch?v=WfkQnZTFXzo&app=desktop

 

[MikeP]

Quote

Better stiff than level

Really Olly! 

[SonnyE]

11 hours ago, Davey-T said:

Video on 10Micron mounts by Per where he mentions levelling at around the 51 minute mark.

Dave

https://www.youtube.com/watch?v=WfkQnZTFXzo&app=desktop

 

Hi Dave, Thanks for that!

I brought back a trimmed link for anyone interested:

 

[SonnyE]

On 12/13/2016 at 13:56, Skipper Billy said:

Another reason is access to the bolt that holds the mount to the plate. It depends on the make of the mount - I couldnt install or uninstall my mount without two plates - I guess I could have a fixed single plate and a hole in the side of the tube but this way easier for me.

If you do go for the rat cage just make sure you use substantial bolts and  plenty of them - I have seen some with 4 x M8 bolts - flexure guaranteed! I used 8 x M14 - it doesnt move!

 

Skipper Billy!

You can't fool an old hand at Industrial Equipment, That is a nice choice using a pipe flange.

Welded to the pipe, excellently rigid. I wish I had a shipyard nearby...

Well done!