Vacuum cleaner type pumps are turbines and have a certain amount of
slip, depending on how many stages they have and other design factors.
They will reach different ultimate vacuums depending on design but
generally will not be more than 100 to 120 inches of water.  Turbines
can reach higher vacuum but these are expensive, closely fitted and
carefully balanced high speed devices, not household vacuum cleaners.

Tracker bar pumps are positive displacement and can reach extremely
high ultimate vacuum.  I am sure they can reach over 400 inches but if
anyone really wants to know I can test one on my gauge calibrator and
get the real number.  The vacuum that they will provide to a pouch is
determined by the speed at which the plunger is withdrawn and the rate
at which the source (bleed and pouch) is leaking.  Also any leakage at
the pump to tracker bar interface needs to be considered.  With a small
bleed and tight pouch and a good coupling to the tracker bar, the
vacuum might get very high with rapid pumping.

I am quite certain that tracker bar pumps will produce much more vacuum
than a vacuum cleaner, and they also have the benefit of allowing quick
bursts of vacuum which are probably better at dislodging crud than a
steady vacuum.  Regular use of a vacuum cleaner will probably maintain
clean pouch wells and signal tubes, but for badly maintained pianos
experiencing clogged bleeds or tubes the tracker bar pump probably
would do a better job with its sharp jolts of suction.

Best regards,
Spencer Chase
Garberville, California
http://www.spencerserolls.com/ 

 [ Atmospheric pressure at sea level will support a water column of
 [ 405 inches height (10.3 meters or 33.8 feet).  How close can the
 [ tracker bar pump approach this limit?  -- Robbie