Building your own pier - how do you connect a EQ3 to a pier?

g__day (Matthew) · #1 17-03-2006, 05:52 PM

For extra stability I'm considering attaching my 5" MAK on an eq3-2 motorised mount to pier rather than a tripod. So I'm considering building the pier's central mount from either tubular steel or 4" square hardwood. Its easy to attach this to a stable base on the floor, but I'm wondering how to attach the top of the pier to the mount itself.

I'd considered buying two 8" square steel plates (say 1/4 inch thick) and connect these by 8 inch long 3/4" steel bolts. The bottom plate connects to the top of the pier and top plate could attach to the mount. But here it gets tricky.

An example is displayed here: http://www.skyshed.com/piers.html or http://www.skyshed.com/gallery.html

Do they make plates to attach eq3 mounts to a pier?

Merlin66 (Ken) · #2 20-03-2006, 08:59 AM

I made up a couple of dummy tripod heads. Folded from 2mm galvanised plate and drilled to fit the top of a pier. The pier was a 900mm length of 3" sq steel tube with 200 diam 4mm thick plates top and bottom.
This allowed the EQ head to be fitted using the existing tripod bolts. If you're interested I can get a couple of photos at the weekend.

g__day (Matthew) · #3 20-03-2006, 04:05 PM

Thank you very much for your feedback!

I'm surprised from your description of how your mount connects to the pier. Folded 2mm gal doesn't sound either strong or very flat?

Too doesn't your connector need a peak from adjusting the mount horizontally clockwise or anti-clockwise so its correctly pointed to celestial South?

I'm ponder whether to simply remove the tripod legs from the mount and attach the whole mount to the pier, or whether to simply take the top half of the mount, which connects to the bottom half with a socket into a well design and fabricate a well in either metal or 2" hardwood.

Simply stuff but a bit bulky and fiddly, and you need to get it very flat!

Merlin66 (Ken) · #4 20-03-2006, 05:20 PM

Can't send photo until the weekend.
The base of the EQ mounting is retained, just remove the tripod legs. The 2mm plate is bent so that there are two upturned sections at each tripod leg position and the existing mounting "lug" on the mounting base and the tripod bolt sit between them. Just like fixed legs. Sturdy as hell. The holes in the bottom of the plate allow for some Az adjustment. I used the same arrangement for a 10" Meade wedge attachment, no problems in 10 years!!!!

g__day (Matthew) · #5 20-03-2006, 08:43 PM

I think I understand this build now, nice move keeping the base. I'm thinking of splitting the base of the mount by "machining" the equivalent base from 4" thick hardwood, then bolting this at a distance. Will upload a few piccys once its done and working.

g__day (Matthew) · #6 22-03-2006, 04:04 PM

So I got a mild steel sheet 300mm * 300mm * 7mm, for $5 to act as the base for the mount...

Any idea how hard, noisy and costly it is to drive 6 * 20mm holes in 7mm plate steel? $55 for the drill bit and $105 (discount for a new 710 watt drill) as the tines on the old (high quality, 550 Watt Bosche drill) chuck slip with the amount of torque need to cut through!

One hole drilled, five to go, thank goodness for ear plugs!

g__day (Matthew) · #7 25-03-2006, 04:30 PM

So the saga continues. The guy that sold me the drill bit gave me exactly the wrong instructions - high speed, no oil. I took the bit back to him and he said its burnt you should have used low speed and oil. I point out 3 days ago he gave exactly the opposite advice, and he said I wouldn't have done that! So a disputed warranty claim on that one!

Bought another drill bit and it works brilliantly so I have the top mounting plate set firmly, now I need to cut a 60mm hole for the head of the mount. But of course everyone is out of exactly that size. They have 10 model of larger and smaller size, but not the one I need...

And of course to smooth the plate steel edges I purchased a angle grinder $85 and to remove surface rust I purchased a wire brush for a drill $10.

So I figure material will end up costing

Plate $5
Brackets, bolts and washers $95
Wood - free from building materials off cuts else it would be about $25
Paint - leftover, else $10

And tools

Large drill + bits $115 + 2 * $55
Angle grinder and brush $95

Already had the shifting spanners, files, drop saw, hacksaws, calipers, protacter, compass etc...

So I am nearing the home straight. Will post a pic and/or construction plans when its all done and polished!

PS

You could buy a basic pier for about $550 - $950. Once I have made my first I can build other ones for around $100 + labour

h0ughy (David) · #8 25-03-2006, 06:12 PM

pictures, diagrams and blood sweat and tears photos please! I like what you have done and would be keen to follow suit.

Merlin66 (Ken) · #9 26-03-2006, 11:49 AM

I use this adaptor to mount a TV systems mount onto a steel pier. Similar to the GM8. The lugs/ bolts take the mounting base instead on the tripod legs. Has worked great for the last 10 years.

g__day (Matthew) · #10 28-03-2006, 10:58 PM

Well its close to finished from a machining perspective, but it still needs a brace then the beautifican or artwork starts!

Its fully functional at the moment, but it suffers from vibration way worse than my tripod. This I suppose is the column not being rigid enough. I have one right angle brace on it but I need two, and of course the drill bit for that right-angle bracket is stuffed. So almost ready to trial but I simply need a new 3/8" drill bit and am halted till I get this. Oh and I have to screw the rather large floor plate to the deck (perhaps with a packing piece to minimise vibration.

So its solid but needs vibration dampening added to the design. Only a couple of hours from finished I guess!

PS

I angle grinded the plate steel square housing the mount into an attractive 29 cm diameter circle for asthetics. It was huge fun doing this! Angle grinders are soooooo much fun

The tricky bit was building a 12 cm square, 7cm tall wooden block that connects the mount to the plate steel (to give the counterbalance room to move the mount head must be sufficiently above plate steel base). Well I countersunk the 60mm well for it (22 mm), and anchored it at four points with bolts, then the really hard bit, building a protuding post of height 27mm within the mount base but seperated from the well... I had the inspiration to sing a 10cm long, 1/4" wood bolt into the dovetail block at the precise position, then cut the head off (more angle grinder fun) and then grind it down until the mount turns freely with the adjusting screws!

God it's heavy now, and very easy to level, so once its rigid it should be fine!

Piccys soon once its all up to scratch!

g__day (Matthew) · #11 29-03-2006, 10:21 PM

Almost finished now, added a second large angle bracket, and forced the base plate up with a second temporary beam to stress the rig to improve rigidity.

I still will tweak a bit more but it is alot more stable, not yet as good as I'd like. I ponder the pier designs with tripod legs with tension wires may be the way to go!

g__day (Matthew) · #12 02-04-2006, 01:48 AM

Well I added one more cross support between the pier and my house - to pre-stress the pier and minimise vibration.

Bottom line is its quite excellent now

I realise the floor connection was more important than I gave credence too. Whilst my design had great load bearing capability, it did not provide adequate rigidity from minute vibration. This is probably where tripod legs on portable piers work well.

But its on a woodedn deck anyway, so there is only so much I can do to stop vibration. Whack the base hard now - like a solid kick that would fling a tripod five feet - and my pier settles down under 3 seconds. A lesser knock has no vibration after a second.

So, as long as I sit still on my comfy adjustable bar stool (with back support) everything is rock solid.

Now just the trimming and painting (artwork) remains. Will take some piccys and upload soon, it was a fun and frustrating project!

g__day (Matthew) · #13 02-04-2006, 11:48 AM

asimov (John) · #14 07-04-2006, 09:25 PM

Got plenty of holes to drill? Do yourself a favour & get yourself one of these mate.

6-30mm In increments of 2mm. $80-$90 Trade price. Not sure for the guy off the street.

g__day (Matthew) · #15 07-04-2006, 10:00 PM

Nice drill bit, wonder what the depth of each step is 5mm?

asimov (John) · #16 07-04-2006, 10:14 PM

Just measured it. Correct, 5mm. If you were to drill 7mm plate you would be counter sunk on one side of the hole by 2mm.

g__day (Matthew) · #17 08-04-2006, 09:55 AM

Or just drill a guide hole and flip the plate but it might be tricky to get perfect alignment. The right tools, patience and know how are the difference between a great result an a botch from my experience.