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Posts Tagged ‘shim’

Duncan’s EQ6/Atlas Mount Hack for Less Than a Dollar.

Dylan O'Donnell - March 5, 2015

At the last meeting, Duncan Gillespie shared a simple and effective way to improve your Eq6/Atlas (or similar) mount for the cost of a fizzy drink. Or less, if you can find someone who’ll sell you the can sans drink.

Cut a length of aluminium from the can to match the size of the male/boss end of the mount head, that slots onto the tripod opening. Doing so reduces the friction between the powdered metal on an already heavy head, so that azimuth adjustments (for aligning to the celestial pole) are as smooth as a Ken doll and easier on your calloused astronomer’s screw thumbs.


Pictured here is mine made from an unspecified vendor of Root Beer, instead of the red cola manufacture you hay have been expecting but shall remain nameless.

Duncan prefers to put the shim inside the tripod/female end, letting the cans circularity fill the space automatically. Other tips he suggests :

  • Use trial and error to determine the actual total thickness of this shim material. Just add another shim layer until the mount boss will not go in then back off one layer.
  • A thin smear of a good quality grease makes a big difference to the smoothness of the azimuth adjustment. I use a molybdenum type which I have had for years and it shows no sign of separating of the components, oil etc.
  • If more than one shim layer is needed, stagger the meeting ends of the shims. eg 2 shims, 180 degrees apart. 3 shim thickness, 120degrees apart.
  • Do not overlap the meeting end of the shim, unless you use the same shim for 2 circuts of the female receptical. Then still don’t overlap, even slightly, the meeting end of the shim.
  • Push the shim all the way to the bottom and make the width of the shim slightly less than the depth of the hole so that the top edge of the shim is not sitting proud above the top edge of the hole or so that it does not contact the base of the mount.


I like the idea that Duncan’s 6″ Takahashi rig, which probably costs more than both my families cars, is made better with this simple fizzy-drink can hack. It reminds me of the discussion in Robert M Pirsig’s “Zen and the Art of Motorcycle Maintenance” about classicism vs romanticism. A classicist will most certainly shun such a contamination of their expensive equipment, opting inside for the custom made, expensive mount upgrade. The romanticist however is satisfied entirely by the equivalent utility in the fizzy-drink can shim method, perhaps even more so through it’s economy.

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