Friday, March 17, 2017

Clock 3 frame and arbors

The frame for clock 3 is intended to be unobtrusive.  It supports the arbors on which most of the wheels spin, except for the center wheel which is supported between two pivots.  I depthed the wheels with the depthing tool and marked their centers directly on the piece of oak that is to become the frame.

I decided to recess the frame like a watch, so that the different wheels are set into the frame to result in a thinner movement.  This ought to keep the center of gravity closer to the wall.  I cut the recesses freehand using a router before cutting the frame.  Although this worked, it wasn't as precise as if I milled it.

After cutting the recesses, I cut the frame out. 

Once cut, I tried the wheels in (no arbors) to fit.  Here are two views.


The detent and the center wheel are supported on two separated cocks attached onto a shelf that mates with the back frame.

The detent cock is set on a threaded rod with a knurled knob that should allow some measure of adjustment once it's installed.
The shelf is supported both by the back frame and two shelf brackets.

Here is the shelf and the wheels, testing for clearance.

The chapter ring is for the minutes only, while the hours are read from a flag attached to the center cock.  Here they are both planned out. 

Both are marked by holes: small holes for the minutes, larger five minute holes.

The hours are marked in binary.

Here are the frame and non-moving parts of the clock being polyurethaned...

The center cock has a steady pin to aid in proper alignment.

The driver arbor consists of two pieces: an inner rod and an outer sleeve with a hole cross-drilled to engage the winding key.

The other arbors are threaded rods, backed with washers to give wheels clearance from the frame.



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