The McCreary Mount Prototype


Here are some photographs of the McCreary Mount prototype under construction.


Two Major Components - Base and Platform

- Each is easily lifted by a single person


Platform Resting On Base


Close-Up of Upper Bearing

- Using 1" glass marbles temporarily during construction.

  These will be replaced with 1" chrome steel balls,

  grade 24 (accurate to 24 millionths of an inch)


Close-Up of Upper Bearing Support

- This adjustment allows for fine-tuning the East/West

  angle of the polar axis


Close-Up of Lower Bearing Support

- This adjustment allows for a latitude range roughly

  between San Diego and Boston (32 to 42 degrees)

  as well as "fine-tuning" the polar axis altitude.


Preliminary Fluid Drive (Used for Testing)

- A 5-gallon water bag with adjustable output through

  two finely adjustable drip irrigation valves.


Extra Strong - It Holds a LOT of Weight!


McCreary Mount With Scope Installed -

And Assistant! :)


During Some Preliminary Testing


Movement Rate Measurement Experimental Setup


Tool List


Hand Saw

Mitre Saw

Drill Press

Hand Drill

Forstner Bits

Numbered Bits

Screwdriver Bits

Carpenter's Square

Framing Square



Construction Notes


In all photographs, please note that there is very little required in the way of "precision construction."


The most critical elements of this design are the "two points," i.e. the main bearings. What is required there is that the bearings be as solidly, rigidly supported as possible, and yet as finely adjustable (each along a single axis) as possible without any "wiggle-room."


Given success in those elements, almost nothing else matters; the platform may be any shape and configuration desired, as long as it is solid and rigid.


Most of the construction is of wood, fastened together with fine-thread drywall screws in various lengths, strengthened with ordinary wood glue.


All cuts were made with hand saws and/or a band saw.


The bearing adjustments are made from 10-32 fine pitch threaded rod with cap nuts at the ends, locked in place with ordinary nuts, to be used for fine adjustment.


Bearing supports are cut from the plastic of a kitchen cutting board. The adjustment screws are self-threaded into this plastic.


When moving to a very different latitude, an electric drill may be used to rapidly move the altitude (lower) bearing to the correct range for the latitude.