Knuckle Size

[Dan Squire]

On  7/29/95 Mr. Wathen wrote on the subject knuckle size:

"I had performed this type of investigation before
on the relationship between Downweight and the distance of the
action arm at the hammer shank center.  The action arm is the
distance from the center pin of the hammer shank to the point
where the jack contacts the knuckle.  I found that this distance
is proportional to the measured Downweight.  Increasing the
distance lowered the measured Downweight.  As you can see making
the knuckle smaller would decrease that distance and would
increase the Downweight."

Mike, may I suggest you reconsider your argument.  Your conclusion is
correct, but only for a special case.  I will submit these question for you to
consider:
1.  How many moment arms are in the hammer shank / knuckle system?
2.  Which one is constant; which one varies?
3.  What would cause the magnitude of a moment arm in this system to vary?
4.  What affects the magnitude of the one that varies?
5.  Assuming that there is a variation in the magnitude of
     the moment arms,  how would this affect the downweight through the
     the action cycle?
6.  What would cause there to be only one moment arm?
7.  What case would cause there to be two moment arms?
8.  What affect would a force vector applied to the knuckle have on the
magnitude
     of these moment arms?  ( Hint: Vary the force vector. )
9.  Assuming a ceteris paribus relationship, when would an increase in
     knuckle size not decrease the downweight?

Respectfully,
Dan Squire
University of Houston

Sorry, no aphorisms this time.