Several years ago I learned the term EI from engineers in the business of designing shafts. The instrument most used was in the $10K+ range, therefore not affordable to most. Not even all shaft companies had these instruments. It took about 2 years to come up with the original affordable EI measuring design. I relied on gravity,removing the cost of hydraulic pumps and controls. The shaft profiles on GolfShaftReviews shows measurements taken with the Fit2Score instrument.
After many years of use, I redesign and improved the instrument. The improved version 7 of the Fit2Score EI shaft measuring instrument will soon go into a second manufacturing run. This animation show it cycling on a shaft. The Fit2Score instrument is owned by 5 shaft companies.
In the version 7 instrument shown here, the gauge was re-positioned to improve accuracy and repeat-ability of measurements. Positioning pins were incorporated into a manufactured weight and the lift design was simplified. A unique self centering shaft support maintains the radius of the earlier design while centering the shaft. The shaft naturally ‘falls’ to the bottom of a saddle. This makes measuring faster and much more accurate. Skillful placement of the shaft in the instrument is no longer necessary.
A hoop strength measuring fixture has been added. It provides a platform to center the shaft under the press and uses the 11kg weight and .0001 gauge to measure hoop deformation. The new driver database structure includes fields for hoop strength readings along the length of the shaft. Hoop deformation is used to in the EI calculation to accurately describe shaft centerline bend profiles.This pulls aside another veil of shaft understanding.
The instrument is now available for $2500. Excel based spreadsheets are included for gathering and analyzing profiles of shafts. Owner have the option of subscribing the the historical knowledge base that is at the core of the reviews on this site. Contact firstname.lastname@example.org if you are interested in this essential instrument for golf club fitters and makers.