Letter from Clockster: Bushings and Brass Inserts

Builders wanting to "improve" upon my designs end up with clocks that do not run.  Here is the most common example:

Clock builder:  "I pressed 1/4" long brass tubes into the front and rear frames...."

My response:  NOOOOOOOOOOO!!!!!!!!!!!!!!!!! This is SUCH a common problem.  Guys think that they can "improve" upon my designs by putting bushings in their frames.  This is THE most common reason for a clock NOT running.  By putting in bushings the builder has decreased all of the 'wiggle room' that I designed into the clock to keep it running for decades.  A slight sag in the frame and the clock STOPS!  And what happens when your clock stops?  Your add more weight which sags the frame even further.
 
My Number Six has been running for almost nine years without a single problem - ever!  The brass tubes are great for spacers, but should not be used in the frame.  Why?  We'll take a common tube that I use a lot for spacers, the 5/32 brass tube that fits perfectly over a 1/8" rod.  The hole I design for that 1/8 arbor rod to run in the frame is 9/64 giving a tolerance of 0.016" 'wiggle room'. 
 
The 5/32 brass tube, on the other hand has an inside diameter of 0.128" for that same 0.125" (1/8") rod, giving us a tolerance of 0.003!!!!!!!!!!!! instead of 0.016".  This will ASSURE that your clock will eventually soon stop.  DO NOT USE BRASS INSERTS IN ARBOR HOLES, unless, of course, you like watching a stopped clock.

Clock builder continues:  "...for 0.187" dia, SS rods... and instead of spacers, just used more brass tubes over the rods and press fit the wheels, pinions, pallets, etc. on them.  Probably overkill, and the next one I build will use the same SS rods, but no "tube bearings" in the frames to see what happens."

My response:  I can pretty much tell you right now what will happen.  With the superior craftsmanship that you have put into the rest of your clock, it will run happily for many decades.