self levelling compound?

[iwols]

hi all weather turning a bit so obsy is progressing again ,pier block finished and mounting screws glued in 

but i now find the pier base not quite level,maybe 2,3mm out ,i know i can get the top plate level by the 4 jacking screws via my mount plate at the top but just wondering if i would be better using self levellling compound,anyones thoughts cheers 

[iwols]

or just add another inch of concrete to the top of the pier base(this time level )roughing the surface a bit and hopefully the 4 studs already in will help secure the new surface or am i being a bit ocd cheers

[Zakalwe]

A couple of millimetres is irrelevant. The process of polar aligning the mount will put the RA axis in the correct position.

 

Stick the mount on, polar align it and the job is a good 'un

[RayD]

36 minutes ago, iwols said:

or just add another inch of cocrete to the top of the pier base(this time level

I was looking at this with mine but had some good advice from a forum member in the know who I think was spot on, and ideally it is not the best route.  The problem you have with making it level this way is the slightest high point can mean you are not really secured, but more kind of perched.

I ended up shimming under the fixing points to get the pier nice and upright, and tight, and haven't had a single issue with it.  You can see the trouser shims under the M16 bolts in the pic below

[Fellside]

I used brass shim sheets from ebay.

K & S 258 Assorted Size Sheet Brass Shim .001",.002",.003",.005" Thickness 2nd1P

You can cut it with scissors. So it is easy to make U shape shims to fit at each bolt location.

Cheaper and less hassle than self leveling compound.

Graham

 

[saac]

8 hours ago, Zakalwe said:

A couple of millimetres is irrelevant. The process of polar aligning the mount will put the RA axis in the correct position.

 

Stick the mount on, polar align it and the job is a good 'un

Agreed, levelling the pier in this way has more to do with satisfying the mind than any tangible effect it will have on your setup.  The mount pier does not need to be levelled  - this is another one of those urban myths like the need for a cubic metre concert foundation.  If you can't ignore it go ahead and level it as best you can your shims sound ideal or levelling compound would also do the job but stop short of grinding and polishing the concrete base

If it were me, and I did on mine, I would be pretty relaxed about it.  Good luck with whatever you decide to do.  Nice neat setup you have there.

Jim 

[david_taurus83]

Adding an inch of concrete is no good it will just crack. Best to use steel packers/shims of some sort like above. If it was me, and I really wanted the the base to sit level on something, I would level it up using washers/shims so the underside of the base is level with your flooring, plug the gaps at the edges by your flooring and fill with a non shrink grout mixture. It runs underneath the gap under your base plate and goes off like concrete. This is the method used for steel columns on concrete bases in industral units.

 

Edit: Or instead of shims you could add another nut and washer underneath your plate, sit pier back on and adjust each nut underneath to get your pier level, though this would need to be grouted up like above so it bears onto solid foundation.

[iwols]

1 hour ago, david_taurus83 said:

Adding an inch of concrete is no good it will just crack. Best to use steel packers/shims of some sort like above. If it was me, and I really wanted the the base to sit level on something, I would level it up using washers/shims so the underside of the base is level with your flooring, plug the gaps at the edges by your flooring and fill with a non shrink grout mixture. It runs underneath the gap under your base plate and goes off like concrete. This is the method used for steel columns on concrete bases in industral units.

 

Edit: Or instead of shims you could add another nut and washer underneath your plate, sit pier back on and adjust each nut underneath to get your pier level, though this would need to be grouted up like above so it bears onto solid foundation.

this sounds a great idea could you recommend a grout suitable(preferably screwfix as one is close by) thanks

[david_taurus83]

Not sure about Screwfix. A quick look on the website and it pops up adverts for tiling grout. This isn't the same thing. No harm asking them but my guess is they'll try and offer you the wrong stuff! You need to look for non shrink cement grout. It's like self levelling compound whereas its quite runny and is designed to fill gaps up to 2 or 3 inches. Example below. I've just realised as well that the picture above is not your pier but another members as I was looking at that when I suggested above but hope you can see the idea.

[Hallingskies]

I had the same thoughts when I did my concrete base and then bolted the pier down, only to find it was out of level by at least a degree or so.  But I went ahead and set the polar alignment up anyway.  After a couple of iterations of the polar alignment routine in PHD, my NEQ6/EQMOD set-up lands my target on chip pretty much first time, and I get very little drift over a five hour imaging session.  So I stopped worrying about the slightly wonky pier and ways of getting it perfect.  I guess you would find the same.

[newbie alert]

I wouldn't use levellng compound or grout..it won't have the compression strength and 90% of easily available levellng screeds won't be good enough for out door use..its supposed to be used with a dpm underneath it..theres only 2 types that I know of that can be used in outside and underneath dpm level and I doubt you could buy them easily..not from a builder' merchant or diy store anyway..