The Sewer Pipe Pier

ZeroID (Brent) · #1 16-10-2011, 02:44 PM

Bit of warm weather and it's amazing what you can get done in the garden. I planted a sewer pipe (unused)
Drilled my concrete slab and bolted a threaded bracket down. Set up pipe over bracket on three bricks and damp isolation. Screwed a 1 meter length of M12 threaded rod to the bracket and then the levelling plate assembly. Did a solar noon alignment, tightend everything up and loaded SKII onto it to see how it all worked.
It's all wrapped up in plastic bags and towels with the head still loaded. First chance I get I can try an alignment and see how good my Nth\Sth guesstimate was.

leon · #2 16-10-2011, 03:56 PM

Well that is different Brent, I do hope however that/that threaded bolt will hold it stable, seems like a small support to stabilize all that weight.

Congratulations on a very unique set up, well done.

Leon

ZeroID (Brent) · #3 16-10-2011, 06:17 PM

Cheers Leon,
The rod doesn't have to hold the weight, it is under tension. It will hold about 4000 lb in that configuration and all it is doing is locking the sewer pipe down to the 10 ton concrete slab it sits on. The leveling plate base is laminated ply about 40 mm thick, glued, screwed and sandwich bolted, you only see one layer above the pipe upper edge. The pipe weighs about 80kg and the base is about 320 wide and with the head loaded and balanced could sit there even without the rod securing it to the slab. SKII is a one hand carry and only weighs in at about 11 kg at present and is balanced on the dovetail bar. It doesn't move much when I give it a really good whack and certainly can't rock on the base.
The Ob floor will be isolated, you can see the begiinnings of it in the shots. I know the design is not 'conventional' but it's going to be a lot more stable and better able to maintain alignment than my moving tripod arrangment. I already have the shed planned to go around it.
SkySlab will come to be ....

frolinmod · #4 18-10-2011, 08:22 AM

Looks good, but two things:

1) do those four bolts really have to be so long?

2) are you really able to balance that scope with only one counterweight?

ZeroID (Brent) · #5 18-10-2011, 09:10 AM

Quote:

Originally Posted by frolinmod

Looks good, but two things:

1) do those four bolts really have to be so long?

2) are you really able to balance that scope with only one counterweight?

No, I just cut a meter length up and used 4 = lengths but now I have established clearance for the lock down bolt I will reduce the height and possible flexure. I will also add a steel crossplate about 3/8" thick and 2" wide across the base plate to spread the pressure load. It's pulling about 200-300 kg under tension to the slab below and it will spread that more to the edge of the pipe.

No, although the scope only weighs 11 kg ( the beauty of Serrurier truss design ) the second weight that was supposed to come with the mount was lost in transit. BUT I have several large G-Clamps which I clamp onto the single weight and all is sweet. This loading of the scope onto the mount was more to see about clearances of the planned Ob shed wall and height over the edge of the roof. In actual fact with one weight and no accessories attached it's not far off being balanced.

jenchris (Jennifer) · #6 15-02-2012, 10:24 AM

Make another weight with a tin can and some melted lead (wheel weights are good) - drill to suit shaft and put it above the one you have.

ZeroID (Brent) · #7 16-02-2012, 07:45 AM

I sold all my old lead on Trademe after I stopped casting my own fishing sinkers. Will take a while to collect more lost weights. Could pour a concrete weight though. Load it with scrap metal for greater mass. Might have to be a bit bigger but easy to do and no hot metal to burn anything. One largish tin can with a pipe down the middle ....... bunch of old nuts and bolts.

But the idea still holds, thanks Jen

jenchris (Jennifer) · #8 16-02-2012, 09:42 AM

I went to a tyre place and asked them for a couple of kilos of old weights - popped them in a wok and used my camping gas stove - the steel bits floated up and I scraped them off with a fork along with the oxide slag and poured the remainder into a coke can with the top cut off. tore off the aluminium when it was cold - perfect.

ZeroID (Brent) · #9 20-02-2012, 12:12 PM

You're just full of good ideas Jen ..

I'll add it to the option list but the concrete is free down in the garage, just need a suitable sized tin. I'll drop a piece of steel pipe through the middle with a threaded hole one side so I can lock it on the CW bar.

Eureka !!

Just found the perfect mold !! I burn hundreds of CDs\DVDs at work, we buy them in bulk in nice deep cylindrical smooth plastic containers with centring holes etc all molded in place. Couple of those will do the trick nicely.