I am sure that many readers can identify with John Phillips dilemma
as he posted in MMD (12.05.13).  There are several things that can
make Tempo tests much simpler.  The first is don't use a test roll,
or at least don't use a portion of the test roll that is not at the
beginning.

A simple solution is to mark any roll with one-half foot tick marks.
Lay the un-rolled roll on the floor and place a tape measure alongside
it and mark off 10 feet in one-half foot increments.  Clearly label
each tick mark.  Do not cover the tracker bar with tape.  Doing so will
change the drag coefficient.  Use a roll that you wouldn't mind hearing
numerous times.

Many other tests may be performed with tape covering a portion or all
of the tracker bar.  The tape used should not transfer any excessive
amounts of adhesive to the tracker bar.  My suggestion is removable
Scotch brand tape, number 811, which I demonstrate in my recently
released DVD on Ampico code.  Masking tape is usually too thick and
causes problems.  All tape will require some clean up after removal.

Cleaning after tape removal should be with "VM & P naphtha" using
a soft, non-shedding cloth.  This can be followed with normal tracker
bar polish.

Does it make any difference at which point of the roll is used to
calibrate the Tempo?  There is probably no correct answer.  One assumes
that using the last half of the roll to calibrate Tempo is a bit
strange.

Would using the center of the roll be better?  Did all manufactures
compensate for roll build up and did they do it in a standardized
manner?  Probably not.

So why not just accept the fact there is no best way and use the very
beginning of the roll for Tempo calibration.

Bob Taylor
Missouri

 [ Petroleum naphtha is a mixture of very many different hydrocarbon
 [ compounds.  "VM & P naphtha" means "Varnish Makers' & Painters'
 [ naphtha", which is a specialty product refined from petroleum.
 [ Ref. http://en.wikipedia.org/wiki/Petroleum_naphtha  -- Robbie