Wednesday, April 15, 2009
After making a few telephone calls and trips to various shops around my area, I found a business that sells 6061 aluminum bar and strap metal that is the right size for the bars and triangles for the flotation system, as well as the drill bits to make the necessary holes for it to pivot properly. The total cost for the material came to about 44 dollars. Moreover, the business where I obtained the aluminum carried it in other shapes and thicknesses so I can get what I need to make any other aluminum alloy parts I choose to fabricate for the telescope. Eventually, I will have to acquire a cylinder of argon gas for my welder, a spool gun and welding wire for aluminum if I choose to weld brackets and other parts to connect the trusses to the mirror box and the secondary mirror cage. I already have a regulator and flow meter, so setting up to weld the aluminum if I choose should be fairly easy. But for now, I just have to find stainless steel bolts or all-thread, nuts and washers to finish the tailgate so I can determine the weight. This is necessary for calculating how deep the mirror box will have to be so the telescope will not be extremely bottom or top heavy. I would rather not have to put 20 pounds of steel on the tailgate to make the telescope balance correctly if I can help it, because I'll have to lift the rocker and mirror boxes, with the mirror inside into and out of my car when I take the telescope to a dark site.
After obtaining the aluminum, I calculated the dimensions of the bar and the triangles that the mirror will rest on and made a plywood template. I then traced out the triangles on the 1/4-inch flat aluminum and cut them out with my heavy duty hacksaw. It was slow but I was able to cut them slightly over-sized. I then took them to my table saw and used a sanding wheel to shave them down then round the corners so they matched the template. Then I cut three bars from the 1/2-inch by 1-inch bar stock. The result is I now have six identical aluminum triangles and three identical aluminum bars. The next step will be laying out and drilling the holes for the collimation bolts and machine screws.