After a week at the F1GP in Melbourne, and Easter Festivities, I managed to get a little bit more progress on this project:
The stack of aluminium bits and pieces are now welded together and the visible external welds have been ground back ready for the powder coating, including all external edges which have been rounded over by draw-filing and sanding.
The mirror support sling linear bearings are installed on M10x110 s/s cap screws and the MoonLite truss clamps are installed (only one bolt each until their exact angle is known).
The 18pt cell is yet to be dismantled fully for some TLC on the buffer and new glide pads are yet to be installed....
Next project is the UTA which will be traditional design but with carbon struts and kevlar baffle....
Still very slow progress while waiting for parts from China, USA and Germany.....
Here is a picture of test fitting of the truss poles and UTA frame..
also a closeup of the beautiful Aurora Precision UTA Clamps which are now installed. The truss tubes are ExelComposites JTW100 full carbon and are now epoxied into the 1.25" aluminium sleeves to which the Aurora Precision clamps attach with s/s socket screws.
While waiting for Mr Postman I decided that the Telrad should match the carbon/kevlar baffle of the UTA so it now sports 0.25mm thick blue/black kevlar/carbon gloss panels attached with 3M 468MP Transfer tape.....
Next little bit will be the focuser board which will be a 6.0mm thick full carbon panel with 0.5mm kevlar/carbon sheet bonded to the outer face .....
Managed to sneak out into the shed for a few hours this week:
UTA now complete
Focuser board is 3mm twill weave carbon fibre panel attached to a pair of 12mm aluminium struts that have been lightened by milling out the unseen side..
Baffle is a sheet of blue kevlar/black carbon twill weave sheet 0.5mm thick (or should that be 'thin') with high gloss epoxy on the outside and kevlar fabric on the inside... (this stuff is tough !!!, went through 3 blades just to cut the focuser hole..)
Focuser is the FTF2015BCR with integrated SIPS Paracorr
Spider is the Astrosystems Heavy Duty II with matching secondary holder with Bob's Knobs and Astrosystems 1/12 4.5"
The UTA clamps from Aurora Precision now have ratchet clamp levers replacing the round knobs to make turning them a little easier...
Hi Colin,
Just the ALT bearings to make and then it's off to the Powder Coaters for the mirror box, rocker box and AZi bearing plate.... I am also considering removable truss pole extensions of about 120mm that once taken off will allow binoviewing without any GPC in the path...
Using prestretched 2mm s/s wire and 10mm linear bearings on s/s M10x100 cap screws, I covered the bearings with heat shrink tubing, then fitted 19mm anodised clamps and s/s turnbuckles to complete the pair.
Each sling runs from the top corner to the diagonally opposed bottom corner, crossing under the mirror, they are located in place using 19mm s/a velcro tape...
Very smooth operation, any movement of the collimation screw is seen as movement of the linear bearings...
(For those asking why?..... this design keeps the mirror perfectly centred without the need for guide posts)
With many thanks to Stefan Buda, who very generously gave up his time to assist with the design idea and then provided the DXF files, I now have the Altitude Bearing arcs ready for the next stage.
Stefan also provided advice on the mounting plates and then drew them up on CAD overnight for me
Many thanks also to John Langridge of CALM Aluminium @ Minto, for his excellent service, water-jet cutting them out of 1/2" aluminium plate. I sent the DXF files to John on Monday and had the finished parts in Canberra first thing Wednesday at a huge saving over the local people.
A little more progress this week, this time on the lower half of the scope...
Mirror box, rocker box, handles, axles and alt bearings are now at ACT Powder Coating ....
Hooray !!!
The Alt Bearings are demountable, each being held on by 3 M8x20mm Stainless steel cap screws which screw into stainless steel 'pucks' that are bolted to the sides of the mirror box,
and once they are removed the mirror box and its precious cargo drop down inside the rocker box for more compact storage....
For anyone wanting a challenge, try hand tapping threads for 18 M6x1.0mm bolts into work hardened 6mm thick 316 grade stainless steel plates......... guaranteed to test your patience !!!