I'm currently building a refractor. I purchased the already finished lens from Sky Instruments of Vancouver, BC Canada (ph 604-270-2813). They sell ready to go objectives, tubing and other parts at very reasonable prices. One trick I've come up with for holding the glare stops in place is using automobile piston rings that are glued in with epoxy to hold the stops in the tube. The seamless aluminum tubing that I'm using is perfect for piston rings from a 1600cc VW piston ring (86mm dia.) The stops are made from Aluminum sheet purchased at the hardware. All of the cutting and shaping and assembly is being done with a Dremel tool, cheap files, hand tools and sandpaper. Get the Edmund book "All about telescopes" and Amateur Telescope Making book 1 for guidance. Both books present lots of useful info.