Time to route the curve in the rocker. Attention to getting the exact radius on both. Will have to match the same radius for the Alt beams using the INSIDE of the router bit not the outside.
Although I have friends with great workshops i have found it more rewarding to make do with a basic tool set at home. Here are some of my friends to date. I did purchase a basic drill press from ALDI for $80. Here is a picture of some of them.
The Altitude Beams begin as two full half circles. I then had to measure 15 degrees to take off each end to leave a total of 150 degrees of movement for each beam.
Used a compass and ruler that begins with measuring 60 degrees then 30 degrees then 15 degrees.
Using my old Altitude beams from my prototype to check that all it OK.
Beams are 6 inches at the widest part of the arc.
The arc is 7 1/4 inches minus the width of the teflon pads so that hopefully I get a match when placed inside the rocker arc.
Bottom and top boards of the mirror box routed and corner brackets ready to reinforce the corners and keep sides square. Bevel cut in the sides and ready to be cut into the bottom board.
Bottom board is 3/4 to support the 3/4 ply mirror triangle. The top board is 1/2.
Its going to be an interesting experience managing all these parts and keeping them square come glue time!
Rocker sides, Mirror cell cut out. Trimming to do on parts, however a Productive day. Impressed with the result using a straight channel fence on the router for the inside of the triangle mirror cell.
You'll love the finished scope. Keep the pics coming !
( I took mine to the Canberra Astro Society DarkSky night on the weekend and soon had a queue of people climbing the ladder to see some of the usual suspects. M42 with colour was a nice sight. One young lady, whose eyes are obviously much better than mine described the colours well, some others could not discern the subtle hues)
Challenging times to find solutions to the following:
1. How to drill holes through two sides of Alloy C Channel to hold the clevis pins that will allow slight movement (rocking) of the bars when glued to the mirror.
2. How to duplicate the same holes through the three required rockers.
3. Something of a challenge using a basic ALDI drill press.
It was all about using clamps on the drill press to get the most accurate result.
4. The final task was to drill a hole through both sides of the rocker and through the ply. Also had to allow for at least 1/16 underneath the rocker by using 6 sheets of cardboard underneath the rocker, close to 2mm in thickness.
Involved dismanteling and twisting the drill press to be able to fit the mirror cell underneath for the final hole. See last picture.
A timely visit from my son helps me build a right angle jig using a hand plane. What a great simple tool! Using it to build square corner support brackets, square surfaces for focuser board. May have to use it for mirror box pole brackets! etc etc.
Time to start gluing mirror box!!
A big day with Box, rocker and beams glued and attached. Teflon pads assembled.
Big day deciding on position of Alt beams so there is clearance of box inside the rocker. Using a large clamp was a big help, clamping both the alt beams and the mirror box in one go.
Used chocks of wood underneath the mirror box to test bottom clearance for position of Alt beams in the side of the mirror box.
Helpful using a pre-sized spacer board inside the rocker box to insure clearance of the mirror box. In my case the mirror box was 17 inches square so I made a board 17 inches long and added the clearance to the side of the rocker around 2/16.
The right angle jig was the most useful tool for the day, squaring up surfaces with a hand plane. re-sizing the teflon pads. There is always a corner that can be squared up.
Setting up the pole blocks. I lost count how many version I tried on creating the mirror box pole blocks.
Settled for a complete split in the block, anchored either side of the pole by M6 bolts.
Opted to insert a central screw counter sunk in the middle of the pole hole to create a more accurate swivel of the block when measuring the 10 percent as calculated using a trigonometry calculator.
The final result remains to be tested.
Time to trim all poles to the exact test length. I have calculated the pole length should be 43.47 inches but will start with them at 45 inches.
Here is a picture of the pole cutting jig i used.
Poles assembled, secondary attached. There is going to have to be some thought and effort to produce a secondary that is placed exactly above the mirror box and that pole placement through each block is consistent and repeatable.
Using shims to align the angle of each truss so that they meet the secondary cage in the same position.
Using hose clamps to lock and set the pole length. Hoping this will account for any variation between individual pole blocks.
After leveling the mirror box I used a plumb bob to see if there is alignment of center of secondary over the mirror box.
Measuring the distance from top of mirror box to the bottom secondary ring using an Alloy rod. Calculated at 41 inches at least until the focal length test.
Total primary mirror focal length of 63.8 minus distance from primary to top of box, minus distance from bottom ring to secondary mirror, minus distance of focal plane (secondary to mid focus). Also accounting for 1.5 inches used on the secondary truss connecting bracket.
