Great post, Tom.
I'd like to add a few comments of my own...
At 03:25 PM 3/23/2010, Tom Wishon wrote:
Up until I got about 10 yrs of golf club design
and R&D under my belt, I too used to stew and
worry over the small things I would measure and
notice in my work. But as I did more R&D and
more design work, I started to learn that there
could be tons of minutia that I could waste my
time on and miss the more important bigger
picture. It was from this that I coined the
phrase that I use at times in my writing we
who design golf clubs and research their
performance now have the ability to measure
things that golfers simply do not have the
ability to note or detect in the form of any
visible or significant difference in the performance of the clubs.
I have one or two clubfitting friends that I
constantly argue this point with. They are
excellent craftsmen but not very good engineers.
An engineer is taught to look at tolerances and
not overspecify, because overspecifying costs.
My characterization of their philosophy is, "Because I can!"
This was one of the reasons I chose to use terms
like Practical and Common Sense in the
titles of my books on clubfitting. Over the
past 15 yrs I have so much wanted clubmakers to
learn to focus on the things that make the most
visible game improvement and forget the others that wont or dont.
Spot on!
And most appreciated.
With respect to lie fitting, the application of
practicality and common sense has led me to
these simple realizations which years of use has proven is viable.
* Any manner of lie fitting is better than
no lie fitting for a golfer who has always
bought standard made clubs off the rack
I'd have to change that to "any adequately
executed manner of lie fitting". See below for
the reason I include the qualification.
* Proper administration of a lie board
fitting will work fine for getting a golfer
into a properly fit set of irons for lie as
long as the golfer does not have an early
release and makes contact between the board and
the iron on the BACK of the sole. For such
golfers, the lie detector or ink mark on the back of the ball is better.
* ...
* If the golfer has ANY hesitation about
hitting shots off a hard surface like a lie
board, get him off that board and having the
golfer hit the test shots off grass using the
lie detector method or ink on the back of the ball
There is a serious problem with the vertical line method: accuracy.
Later in his post, Tom suggests +-1* as the
tolerance. I know folks who would argue with
this, but I think it's right for anyone short of
a premier player (scratch, Tour quality, etc).
They might need +-1/2*; I know a Tour player to
whom this would make a difference on his good
days. (His clubfitter argues for even tighter
specs for him.) We'll get back to the azimuth
errors involved, but let's use 1* for a moment.
In order for the "Lie Detector" or ink method to work, you need to be able to:
(a) Align the ball to within 0.7*.
(b) Read the mark to within 0.7*.
(For the engineers among you, I say 0.7* rather
than 1* because the alignment and reading errors
add. It's 0.7* rather than 1/2* because they
probably add square-law -- statistically --
rather than arithmetically. I simplified 1/sqrt(2)=0.707)
Aligning and reading to this accuracy is hard. It
may be doable, but it requires more than what has
been described so far in this thread. Consider:
(a) I went ahead and did an alignment exercise a
few times by eye. Then I actually measured how I
had the ball aligned. I tended to be off by more
than 2*, but never more than 5*. So aligning by
eye is INADEQUATE EXECUTION OF THE FITTING METHOD.
If I take a 90* "alignment tool" with me, get
down in a Camilo Villegas crouch, and align the
mark using the tool, I can get to within 1*,
which qualifies as adequate execution -- even if
not down to the 2/3* that the math suggests we
need. (The tool is easy enough: a CD case with a
square edge was what I used on a carpeted floor.
It has to be long enough along the ground
(undoubtedly longer than a CD case for range mats
or grass) and a good 90* angle.)
(b) The impact labels supplied with the Lie
Detector have 2* marks, and GolfTek says they can
be read to 1*. Without those labels, I doubt you
could read a right angle by eye to the required accuracy.
So, while ink and Lie Detector work, they won't
work well enough unless you are really careful
with both alignment and reading. "Careful"
probably means, "Use a tool for each."
We can debate the minutia until the cows come
home, but at the end of the day, as long as each
iron is fit within 1* up or flat of being
perfect for the lie, this is not ever going to
harm the golfer with the exception of the tour
player level of ball striker or the very high
swing speed golfer. The greater the distance on
the shot, the more a 1* error in lie at impact
translates into meaningful differences in azimuth of the shot.
That is right, but anybody reading this has to
take into account the context Tom cites. We're
talking about greater distance due to higher
clubhead speed, not greater distance due to a
longer iron. Longer irons have less loft, so the
azimuth differences due to a lie error are smaller, not larger.
Thanks again, Tom.
DaveT
