This pier is well overdue!
I should have done this a looong time ago, but I live in a rental and wasn't sure about putting a pier in the back yard.
My Rent inspections are very infrequent these days, approx. every six months, and I'll have to remove the pier each time one is due.
Having to remove and replace/realign the pier has got to be less trouble than setting-up every time I want to use my gear.
The idea is to have the base set into the ground so that I can cover the exposed concrete footings and studs with a cut-down irrigation valve box(see pic) which shouldn't attract too much attention from the inspector
I'm not going for an observatory unfortunately, there are too many sheds on the block already,
but I do plan to leave the mount set up on the pier with a removable weatherproof cover over it.
I have bought the materials already, these were offcuts from the local steel merchant.
The tube is 770mm long, 140mm OD with 5mm thick wall, the base plate is 200mm square by 10mm thick, top plate is 150mm square by 12mm thick.
Gussets are 5 or 6mm thick, 400mm long. These I haven't got yet but HRS strip is easily obtainable.
The studs for the footing will be M16, welded to a frame and concreted in.
The bolts that attach the mount adaptor are M10 in 316 stainless.
I'll be welding tomorrow, which concerns me a little as I haven't really used a welder since I was in high-school, so the welds are likely to be a dog's breakfast by the time I'm done
I have read about the plates warping during welding, but I plan to tack the buggery out of the pier before I go back and make short passes with plenty of cooling time between.
Dunno if that will work but I have my fingers crossed.
I have attached a couple of images from my roughly thrown together 3D model based on the materials I have, they're pretty basic, I haven't bothered to 'pretty picture' render them.
Bolts are shown in the place of studs as an example only. The studs will only have maybe 40 or 50mm exposed from the surface of the concrete.
For anyone interested in getting a better look, the following link is to a 3D PDF file that you can check out various preset views I have made, or, you can rotate and zoom the model.
To use:
Click and hold the Left mouse button while dragging to rotate.
Hold down both buttons at the same time to 'pan'.
Takes a little getting used to.
The link: http://s000.tinyupload.com/download....29599595082340
EDIT: DO NOT open the pdf in a browser, it won't do anything bad, just that the 3D will not work.
It must be opened in Acrobat Reader for the 3D feature to work.
I'm in a rental property and have a 'permanent pier.' I wrote to the agent showing a photo of the pier just placed on the ground where I wanted it positioned (minimum lights and maximum horizon) and asked for permission. I told them it would be completely removed when I vacated and I got their permission fairly quickly.
Thanks guys.
Charles, I had considered that but if the owner says no, then thats it, final.
First change already....
Picked up more hardware on the way home from work this evening... studs and nuts are now 3/4" instead of M16.
Doesn't sound like much of an increase from 16 to 19mm but when you're holding one of each size allthread in your hands, the 3/4" makes the M16 almost look flimsy.
I'd have used M20 if Bunnings had it.
Progress so far.
Well the weekend wasn't as much mine as I had thought.
Saturday:
After a cruisey morning, a friend dropped in and asked me to do some machining for him, three or four hours gone.
A few other people dropped in for a visit thru the day so more time lost.
I did get the drilling done in the top and bottom plates tho.
This forced a reversion back to the M16 thread.
While stepping the holes up in size on my milling maching, I discovered I don't have a 20mm drill or end mill. Drat, could've sworn I had one!
Anyway, did have a 16mm drill.
Photo 1: Materials.
Photo 2: Sizing her up.
Photo 3: Drilled end plates.
Sunday:
Another cruisey morning (I love slow start weekends with a few espresso's, ciggies and reading.)
My dad had me help him with a bit of shopping for the motor home he is renovating, a couple of hours gone at Bunnings.
I did however find a few things I needed, and I was able to grab the M16 allthread to replace the 3/4" allthread.
Back home and 3 trips to Bunnings later (My car can only carry five or six 20kg bags of concrete before the rear wheels rub the guard) I repaired the wheel on the wheelbarrow. Had to re-tube the 6.5" x 8" wheel. These things are a nightmare! When fixed I started digging a hole.
I had decided to compromise on the amount of concrete to use.
Not enough and the pier won't be super stable.
Too much and it's going to be a lot of effort mixing concrete, and then sometime in the future when I move house, disposing of a huge block of concrete.
A friend of mine has 300kg on his pier and his astro gear is much heavier than mine, and he works at a much, much longer focal length than I do(for now) and he has never had any issues, so, I shot for the 300kg mark.
I dug the hole 600 x 600mm square by 600mm deep. The plan was to leave the concrete 100mm below ground level so the studs can be concealed under the irrigation valve box during rent inspections, which means the hole was roughly(try digging a perfect cube ) 180 litres, or approx. 360kg of concrete.
Four 600mm long M16 allthread rods were bolted to an MDF template of my pier's baseplate, then a re-bar frame was wired to the allthread rods(imagine naughts-and-crosses pattern when seen from above) all of which was set into the hole, checked for height below ground and leveled.
I bought 18 off 20kg bags($5 ea) and used 16 of them, so I put 320 kg into the hole. I re-checked the level of the studs and walked away pretty exhausted after all the hole digging and concrete mixing in the wheelbarrow two bags (40kg) at a time.
By this time it was getting late so any further work will have to wait for next weekend.
Monday:
This afternoon, after the concrete had cured a little, I removed the MDF dummy baseplate and checked the pier baseplate. It was a wriggle fit, but it did fit! Hoping the fit won't change after welding. Nothing a die-grinder can't fix
Looking forward to completing this next-weekend!
Unfortunately I was rushing around alot on Sunday and didn't get many photo's:
Photo 1: Freshly concreted.
Try to ignore the dead grass and sand (dirt). We haven't had any rain for... 100 days or something?
Photo 2: Test fit of the baseplate... sweet!
Edit: The stud in the foreground of the second photo appears to be leaning to the left, but it didn't look that way in person. I will have to investigate tomorrow. I think it's an illusion as the base plate would have never fitted with its tight hole clearance!
I'm thinking of getting a TeleGizmos 365 Series for the times when I'm using the scope over a few week period and building my own motel scope version from scratch for the long term cover when the scope is not in use for months end.
Interesting, I've not seen either of those before.
Yes one idea is similar to the moteloscope but for the EQ6 only, no scope. It wouldn't have the bottom framework tho, was thinking of a vertically hinged clamshell like design that would seal around the pier tube.
I figured it's not that difficult to undo the dovetail and remove my little astrograph leaving just the mount to cover.
If my scopes were any bigger or heavier I'd probably go for the moteloscope idea.
Well, another weekend of not enough free time.
I spent far too long playing with my new sand-blaster on Saturday, and all I learned for my time and effort is that I need a bigger compressor, which is going to set me back about $1k new.
I'm going to haunt Gumtree until something suitable surfaces at the right price.
I did eventually get around to welding, got the two end-plates on but no gussets as yet.
My welding is, as expected, crap. But it has been 25 years since I've done it!
Welding is just as I remember, you start to get a feel for it and think 'this one feels good' or 'this one feels bad' but then when you chip the slag off, you see that the one that felt good is crap and the one that felt crap is good....
I therefore have some really nice welds and some chicken s..t
I will grind back the embarrassment and touch up the welds.
Yes I know this is frowned upon by seasoned welders, but I'm not welding together a pressure-vessel here, this is backyard hack time.
The gussets will have to wait until next weekend. I tried to cut them with a cut-off blade in my 5" grinder but it was slow, the work kept grabbing the blade and looked like crap.
I have two band-saws, one vertical for wood and aluminium and one horizontal for steel. The vertical is much too fast for steel so would just blunt the blade if I tried.
The horizontal has the ability to be stood in a vertical mode with a bolt-on work table, but I decided it would have been painfully slow cutting thru 8mm thick HRS for ~500mm.
After the failure of the grinder&cut-off blade combo, I went back to the band saw and tried it... red face time, it works much quicker than I had expected!
The gussets will need some dressing up, then they will be tacked in place and welded next weekend.
In the mean time I've mounted the pier in place and it feels very rigid!
Leveling was quite easy too. Surprisingly easy.
I've cut a slab of aluminium to size for the EQ6's adaptor plate, that will hopefully be turned & milled thru the week after work.
Until then... check out the photo's I didn't take... sorry
I based my "Rental Obs" on the pier plate but ended up on the flip top lid version instead.
Hi Malcolm, you've put quite some work into your mount!
I'm trying to avoid any type of base or platform around the pier, hence why I'll not be following the motel'o'scope style.
I wonder, with all that surface just under your mount, will your scope clear it when pointing near the zenith/upper meridian?
I wonder, with all that surface just under your mount, will your scope clear it when pointing near the zenith/upper meridian?
All tested before installing the computer section below. Seeing it is a flip top lid the upper section is no problem. To keep the profile low, I will be parking in a sideways position.
Free time has been hard to find lately but I've managed to get a little bit more done.
As mentioned above (post #14) I had attempted to cut the gussets from an 8mm thick length of HRS(hot rolled steel) flat bar with a cut-off wheel in an angle grinder. This turned out to be much more difficult and more time-consuming than I had thought! Also, no matter how hard I tried, the cut was about as straight as a drunk man walks.
I then tried the horizontal band saw in vertical mode, an idea I had originally dismissed as too slow, and as expected it was slow going but quicker than using the cut-off blade. Best of all it was much easier to keep a very straight cut.
The gussets I had cut were the half-cut HRS I had abandoned with the cut-off blade and these were far from perfect.
Last weekend I decided to start over, so I marked up new lengths and started cutting.
Things were going great, slowly, until about half way thru the first cut(~250mm) when BANG!, the bandsaw blade snapped, yay!
I was given a spare blade when I got the bandsaw about 6 years ago, but do you think I could find it? No hope!
Being late Satruday, my local(hardly) Hare&Forbes store was closed and I would have to wait 'till I could get there thru the week during work hours to buy a new blade, so I now turned my attention to the aluminium plate for the EQ6 adaptor also mentioned in post #14.
I dressed the ali in the milling machine to get everything squared, I radiused the corners then drilled and tapped the four bolt holes (to attach to the pier), then I moved to the lathe to turn the recesses to accept the dangly under-bits of the EQ6.
Problem.
Turns out the largest chuck i have for the lathe can't accommodate a 150mm square chunk of ali. Damn.
I looked over at the milling machine and decided my only option was to somehow clamp the adaptor plate to my rotary table to allow me to make round stuff on a square machine. This is not ideal but I had no other option.
The rotary table only has a 110mm diameter work table so I had to bolt a jig to the table that could hold the work.
The jig was quick and nasty, being a piece of MDF, but solid when bolted to the table with three t-nuts and then the work bolted to it with four M10 cap-head bolts.
After much handwheel turning, the completed adaptor plate was removed and deburred and test fitted to both the EQ6 and the pier(seperately, it was raining, finally) with great success. I'm pretty happy with it.
This weekend I hope to anodise the adaptor.
I can't decide which colour to use(I have many of these colours at hand: http://www.usspecialty.com/color.php) or whether to keep the machining marks or lose them.
I have to admit I do like the look of the Paramount gear, so maybe I can use Bordeaux Red and keep the machining marks... but then I also like the idea of bead blasting to remove the machining marks and use Black BK....
Anway, I will post a picture of the raw machined adaptor hopefully later today.
Photo 1: Mount side, machine marks make it hard to see the recesses, but they're there.
Photo 2: Pier side. 316 stainless hardware.
Photo 3: Quality jig on the rotary table, it did the job
I am envious, a mill would be really handy for what I want to do pier wise. Try as I might I just can not justify one though. That does look like a nice solid mount plate.
I am envious, a mill would be really handy for what I want to do pier wise. Try as I might I just can not justify one though. That does look like a nice solid mount plate.
They are soooo handy. My mill and lathe are just cheap chinese hobby machines, but that is all I could afford at the time, I also don't have a whole lot of space.
When I say cheap, they were really quite pricey but the cheapest around at the time. The same machines now would cost me almost half as much. With the same money I had paid, I could buy much more solid and capable machines today. Oh well.
) 180 litres, or approx. 360kg of concrete.
