Constructing a dob

ust thought of another source of Aluminum tubing. There are sweeping brush handles available that are made from about 20mm to 24mm light wall aluminum, about 1.2m long, there may be longer lengths available too. Industrial cleaning suppliers might be a source. Should be cheap too

Got a price of Euro 7.26 + VAT each for approx. 1.5m handles from a local company.

Thanks Michael. Price sounds great. I'd be interested to know how thick the wall of the tube would be. It needs to be at least 1-2mm I reckon due to the length involved. Doubt it is at that price.
Cheers,

Mike, he rang me there just a min ago and gave me a few numbers.
The main supplier to them for aluminium tubing is a company in Cork called
AMRI - 021 4316750

There are also 2 places in limerick.
Jer Mc Keowen - 311950
and Jer Reedy - 431182

You can say you got the number from Speedline.

Hope this helps.

Thanks Frank for the leg work. I appreciate it.

I just came across this on the BnQ website:
tinyurl.com/2beb7d
Expensive enough for just one tube.

Just off the phone to BnQ in Liffey Valley.
2m x 20mm diamater x 1.5mm think = €18.14 - I would need 8 of them. I wonder is 20mm too narrow??

1m x 20mm square section x 1.5mm thick (for mirror cell) = €10.63 - I would need 3 of these.

Also looking for 1m x 0.5m x 3mm thick sheet of aluminium, if possible, for the secondary cage.

Hi Mike

From "The Dobsonian Telescope" by kreige and berry they recommend the following

diameter of truss pole = focal length / 80
which for a 16"f4.5 gives .9 inch or 23mm in o.d.

they also recommend a thickness of .049 inches(1.25mm) for a recommended od of 1inch.

Yes Matthew, I'm afraid I picked up this terrible condition of aperture fever alright. Building a 16" f/4.5.

Nice, but what I would like to know is how much that 16" mirror will cost and which company would be the best to get it from, for future reference of course .

Hi Mike! Might i ask what size dob your building??? Is this project fueled by the sight of Dave Lillis`Monstrous dob??? wow that doesnt sound great! :lol: Dave has given us all aperture fever!

Yes Matthew, I'm afraid I picked up this terrible condition of aperture fever alright. Building a 16" f/4.5.

Its a terrible blight spread by the need to have bigger aperture. Whoever said size isn't everything never owned a telescope. :lol:
Looks like this is coming together well for you Michael, can't wait to see it. :!: