CDK17 arrives

[Gama]

Greg, dont use any mechanical devices to lift.
Use 2 friends. I did and mine was a 20", which is heavier than yours.
Its so much safer using 2 people, and no scuffs or scratches either.

Took 5 minutes to put on the mount, and i have a fork mount. Yours should take less time.

theo.

[gregbradley]

Thanks for that. I'll get my son to help me.

Cheers,

Greg.

[gregbradley]

My Pegasus pier arrived today all 97kgs of it!

Most of the bits and pieces are here now. Just needing a bit more work on the observatory and an extra counterweight and shaft extension and I am ready to put it all together ready for first light.

Greg.

[renormalised (Carl)]

***Cracks the whip on Greg to get him moving!!!***

[gregbradley]

Originally Posted by renormalised

***Cracks the whip on Greg to get him moving!!!***

Yes its all a bit slow isn't it.

I am still waiting for the 3rd counterweight. Then next week I finish the observatory and mount everything.

Greg.

[Bassnut (Fred)]

Yeah, what do you recon about those stainless steel counter whieghts at some $400 a pop?.

[Doomsayer]

It does hurt buying additional PME counterweights - but they are a thing of beauty in my opinion, solid stainless, very nicely machined, functional and add to the visual appeal of the Paramount - it's the shipping that stings a bit. I have four PME counterweights and a 24" c/wt shaft. Having a longer shaft is the way to go if you have room.
guy

[Moon (James)]

Yeah, what do you recon about those stainless steel counter whieghts at some $400 a pop?.

I recon you get what you pay for

[gregbradley]

Got the roof on today, I have the pier, the shaft extension for the PME and hopefully pickup the counterweight tomorrow.

Observatory needs a bit more work but will be working on it every day this week to finish it.

Getting closer to first light.

Greg.

[bert (Brett)]

On the counter wights:
I once had to bore out a paramount weight so it could be used on a Ap1200. It is incrdible hard steel, they did not take any short cuts on the metallurgy thats for sure. It left the poor lathe screaming and bouncing start to finish.

Sorry for the off topic.

Brett

[gregbradley]

My roof does not roll very easily, in fact it fights you pretty hard.

I have 4 wheels per beam which is 100 x 50mm 3mm thick walled steel.
I put M10 bolts through holes drilled in the beam as axles and 75mm wheels.

They are tracking through a 100mm C purlin mounted on its side.
It does not allow much margin as the wheel takes up a lot of the 45mm available and any non parallel of the track etc means it scraps the back of the purlin.

I am think of mounting the purlin on its back and fixing some angle to prevent the roof from blowing off. That should give it more margin to roll without hitting the back of the track so easily.

Any other suggestions? It may be better if I post a photo.

Greg.

[bert (Brett)]

I always use a captured rail for observatories... ie like a c section but with a rounded bottom that makes the wheels self centering. It makes it very smooth, prevents lift, very low friction and quiet .Check out guys in the attached photo (ignore the guy in the background).

The thread and photos here

http://www.iceinspace.com.au/forum/s...ad.php?t=51449

You could try using a wheel that is mounted horizontally in the c-section (both sides) to the roof to stop the scraping. It is a compromise tho.

Brett

[gregbradley]

Hi Brett,

I like the captured rail. But the wheel is the go. I had trouble finding a suitable wheel as they often seem too wide and then getting a bolt that doesn't stick out the other side of the wheel limiting clearance even further.

Where did you get the wheel and axle from?

Here is a photo of my current setup which seems to be scraping or too much friction:

http://upload.pbase.com/image/125406721

Greg.

[Moon (James)]

I originally had rubber v-groove wheels on inverted angle iron. I changed it over to cast iron v-groove wheels and the difference was amazing.
James

[marki]

Greg I can see two problems with what you have done. The axle setup you have will allow too much flex and if you have limited clearence it will bite and stick. Secondly the rubber on the wheel itself will also bite. Could you get a proper mounting bracket made (a u channel that fits the 4 x 2 perfectly with a short stub axle welded on). You could also try shaving down the rubber or remove it entirely leaving the metal rim to run in the channel (probaly need a larger diameter wheel to keep clearences the same).

Mark

[gregbradley]

Originally Posted by Moon

I originally had rubber v-groove wheels on inverted angle iron. I changed it over to cast iron v-groove wheels and the difference was amazing.
James

I saw cast iron V wheels at Bunnings.

Originally Posted by marki

Greg I can see two problems with what you have done. The axle setup you have will allow too much flex and if you have limited clearence it will bite and stick. Secondly the rubber on the wheel itself will also bite. Could you get a proper mounting bracket made (a u channel that fits the 4 x 2 perfectly with a short stub axle welded on). You could also try shaving down the rubber or remove it entirely leaving the metal rim to run in the channel (probaly need a larger diameter wheel to keep clearences the same).

Mark

I don't think the axle flexes as its 10mm steel and it goes through the 40mm steel tube. But the wheels plus the bolt head add up to about 40mm and the track is only 45mm max wide so hardly any margin for error.

So a thinner wheel would help or a different track that is wider.

Greg.