Constructing a dob

I didn't think of you cutting out a circle - yes, a jigsaw would be best. Make sure you get a blade that suits the timber you are cutting e.g. one with larger teeth for hard/rough wood, one with fine teeth for pine/soft woods. If the surface of your plywood is nice and smooth, then just let your hand (with the saw) do the walking by following the line you make. Sometimes people put masking tape over the wood, but usually this is just to minimise splintering. Sometimes, the wrong masking tape will drag the plate of the jigsaw. If you're worried about how smooth you will make your cut, just take your time!

Cheers.
Only concern I still have is with the bearings. They need to act very smooth, like a wheel, as they are in motion.

Anyway, here's a pic of the base boards and the trianglular supports for the mirror cell which I cut this evening:

www.astroshot.com/Dob/7.jpg

Will need to sand down the edges and varnish them.

Well, after much thought, I decided to get a router today. I just don't have enough confidence in my abilities with a jigsaw to cut a smooth circle. So, after work this evening, I picked up a router in B&Q. Never used one of these before. I have to say, these are a joy to use. Makes cutting wood a joy to do. Anyway, here's a pic of work in pregress:

www.astroshot.com/Dob/8.jpg

And here's an image of the finsihed disc. A few splinters came off when cutting into the grain. However, for my first time with a router, I'm quite happy with the result. I can sand it down after.

www.astroshot.com/Dob/9.jpg

Cost of router was €109. This included the case, bits, etc. Also had to buy a pipe cutter. Unfortunately, this was difficult to get. Most shops only had ones up to a 1 1/8" in diameter or had ones for plastic pipes. I needed 1 1/4". Only place I could get one was in B&Q and that was for €34. Works for pipes from 6mm to 50mm.

Clear Skies,

Nice work Michael. Keep it up. I'm watching this with great interest.

Was cutting the second ring for the secondary cage when the "bit" (don't know the technical term for them cutting blades :oops: ) in the router broke. Made a dash to B&Q and bought what appeared to be a standard size one - 1/4". Came home and found it was too small. Turns out I need one at about 5/16" or 8mm in diameter. Must get another one tomorrow. What's with all the different diameters?

Ordered the Pivot kit, spider, secondary holder, sling material and teflon from Astrosystems this evening.

Also ordered the Ebony Star Laminate and Kydex from Meredian Telescopes.

Only item left now are the lower truss clamps. Still haven't decided what I want to do here. Ideally, I'd like to attach them directly on top of the mirror cell. Would keep the mirror box smaller. Any suggestions?
What would people think of these: www.focuser.com/cgi-bin/dman.cgi?page=pr...&product=TC-125D
Would they do the job? I could buy 4 of these, one for each corner and attach them to the top rail of the mirror cell.

For the lower truss clamps, I'll take a pick of what's on the scope here so you can decide if you want to do something similar.