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A further visit to the scrap yard produced some 25 kg [50lbs] of really useful lengths of aluminium plate in almost new condition:
A seriously hefty, 117cm length of 20mm x 200mm aluminium. [46" x 0.8" x 8"]
Over 3 meters of 10mm x 150mm aluminum. [10' x 0.4" x 6"]
The massive length of 20mm plate will provide more than enough material for a completely new and bigger support fork and base plate without requiring lamination. This piece weighs 13 kg or 27lbs on its own. 20mm x 200mm aluminium is easily sturdy enough for screws to be used directly [and invisibly] from beneath the fork arms to hold a really stiff, base support fork together. The much greater width of 8" over the previous 6" wide plate opens up new and sturdier options in fork design. I shall be careful not to waste it by merely copying my present fork design.
Sawing it will be a lengthy process unless I can persuade a local engineering company to let me borrow a few minutes on one of their industrial band saws. The existing 10mm front plate for the fork will provide an anchor for the turnbuckle, polar altitude adjuster. A 10mm diameter male threaded U bolt should be ideal. I will need another for the other end on the polar axis housing. All this can wait until I have made the new, much thicker base fork.
Sawing it will be a lengthy process unless I can persuade a local engineering company to let me borrow a few minutes on one of their industrial band saws. The existing 10mm front plate for the fork will provide an anchor for the turnbuckle, polar altitude adjuster. A 10mm diameter male threaded U bolt should be ideal. I will need another for the other end on the polar axis housing. All this can wait until I have made the new, much thicker base fork.
Having so much more of the 10mm x 15cm strip available is [almost] pure luxury. Since it allows me to relax my previous careful rationing. With the consequence that I now have much greater freedom in design if need be. I could, for example, cut a 90mm wide strip to fit neatly inside the original saddle channel. 10mm x 90mm aluminium plate is easily stiff enough to really firm up the original 5mm thick saddle.
The saddle/dec fixing, Tollok bush would be bolted directly through both the original 5mm thick channel and the reinforcing 10 x 90mm strip. With a worthwhile increase in the saddle's main beam depth to 15mm. The two [OTA] tube rings would also be bolted right through at each end for extra stiffness. I shall have to order some longer, hex socket head, stainless steel screws.
An image showing the highly decorative, domed, brass nuts which I have used to replace the rather agricultural, galvanized variety. These sit on bored out stainless steel washers for load spreading. The heavy, knurled brass cylinder is surrounding the Tollok bush where it fits the declination shaft to the saddle. There is nothing like a bit of overkill where avoiding flexibility is concerned. The brass bush has nearly a half an inch wall thickness.
The 5mm thick worm support plate under the flange bearing will be replaced with much sturdier 10mm once I know how large it needs to be. I have contacted AWR in the UK [again] for their advice on a stepper motor system with control handset to suit my new mounting.
The saddle/dec fixing, Tollok bush would be bolted directly through both the original 5mm thick channel and the reinforcing 10 x 90mm strip. With a worthwhile increase in the saddle's main beam depth to 15mm. The two [OTA] tube rings would also be bolted right through at each end for extra stiffness. I shall have to order some longer, hex socket head, stainless steel screws.An image showing the highly decorative, domed, brass nuts which I have used to replace the rather agricultural, galvanized variety. These sit on bored out stainless steel washers for load spreading. The heavy, knurled brass cylinder is surrounding the Tollok bush where it fits the declination shaft to the saddle. There is nothing like a bit of overkill where avoiding flexibility is concerned. The brass bush has nearly a half an inch wall thickness.
The 5mm thick worm support plate under the flange bearing will be replaced with much sturdier 10mm once I know how large it needs to be. I have contacted AWR in the UK [again] for their advice on a stepper motor system with control handset to suit my new mounting.
Click on any image for an enlargement.
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