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Lee
22-10-2006, 10:27 AM
Hi guys

Does anyone know of a local (preferably) source of various counterweights for a G-11 shaft..... I'm after something lighter than the standard Losmandy 11lb weight, due to difficulties in getting an ED80 to balance. At present, it *just* balances with one 11lb weight right at the *very* top of the shaft - with sub-micron clearance between the weight and the RA servo housing - I can see disaster looming at this rate.....

[1ponders]
22-10-2006, 11:37 AM
The cheapest way will probably to find an old weight set somewhere and get the hole bored out to shaft diameter.

Garyh
22-10-2006, 12:00 PM
Hi Lee,
Had the opposite problem, needed another 3 kgs to balance all my gear, someone suggested dumbbell wieghts which I tried. They are cheap but boy are they hard to drill out! and you can`t lock them in position also.
Got a wieght made up at the local engineers, 35mm hole and a grub screw to hold in place for a total of $26. Made from a offcut of mild steel bar 90mm round and about 100mm long I picked up. Good coat of paint and looks like a bought one.
That would be the easiest way to go for you....:thumbsup:
Cheers Gary

Lee
22-10-2006, 01:06 PM
Thats what I had suspected about dumbell weights Gary - I suspect I need about 3kg or so, but half way up the shaft - held in place securely....
Losmandy sell their 7lb'er for US$45 I think, that would be over A$100 I'm sure by the time it got here, all for a chunk of metal.....
Will investigate some local engineering places - Newcastle must have more than a few metal joints!
Would you mind posting a pic? What does it weigh? 3kg?
Thanks!

[1ponders]
22-10-2006, 01:11 PM
I use a combination of my first suggestion and what Gary has suggested. I have two 7(1/2?) lb weights drilled out and two pieces of 75mm mild steel bar (50mm thick) with bolts taped into them. They are very handy. With a 21lb (Losmandy), 3x7lb weights and these two I can mix and match as needed. Mind you this is enough for two mounts most of the time.


Oh and a 7lb sledge hammer head that can be bolted to the bottom of the shaft if I need it :lol:

rogerg
22-10-2006, 04:38 PM
There's this farmstay I used to observe at on a regular basis with a fellow amateur astronomer. One time he needed an extra counterweight. The farmer dug around and pulled out a cog from a early 1900's piece of farm machinary. The farmer proceeded to attach it somehow or another (drilling, welding, whatever to get a lock nut on it... What better way to add character to a scope :thumbsup:

Garyh
23-10-2006, 08:30 AM
Heres a pic of it Lee, gave it a coat of primer and hammer finish paint and put a piece of aluminium on the lock bolt for a finger grip. Comes to just under 4kgs, was 5 before the hole!
Seen some strange counterweights on the net, everything from concrete to diskbrakes to old lead batteries!! now I hear farm machinery too!!!
Cheers Gary

gbeal
23-10-2006, 12:21 PM
I got weights made with a local engineering mate.
Mostly they were old pulleys and all that was required was a trim to clean them up, with a round on the edges, and the hole bored to fit the shaft, which I recalled being 32mm.
They worked well, and when I got the Tak mount I simply got a plastis bush made to bring the hole down to 19mm which was the Tak shaft.
Now those same weights are out to 28mm on an AP mount.
Cheaper than importing, and just as good. If you get them straight from the lathe you can simply clear spray them, keeping the metal look, or use a "Stainless" look alike spray, I did.
Grub screw with a know to clamp and you are away. Piece of cake for an engineer.

mick pinner
23-10-2006, 05:39 PM
l made these for both Bird and Striker, you could use odds and ends but if you want something that looks good hanging of an expensive mount you should be able to get these made at a local engineers for about $150.00 not cheap but a lot cheaper than originals.

Geoff45
23-10-2006, 08:01 PM
I bought a 3 kg piece of 100mm diam mild steel for $15 and got a mate to machine it for a bottle of red. It also looks better than the rough chunk of metal that came with my Losmandy.

Lee
23-10-2006, 08:39 PM
Currently have a different interim solution - no lighter counterweight? - make the scope heavier! My D70 is perched on top currently acting as a weight! A $2000 counterweight.... :screwy:

gbeal
24-10-2006, 05:08 AM
Lee,
I forgot about Mick's machining skills, sorry Mick. My suggestion is get him to make a few for you, and to start with a lighter one.