Shaft Certification
Each raw, uncut shaft is first tested for six specification parameters:
1. Length
2. Weight
3. MOI
4. Balance Point
5. Frequency
6. Radial Integrity
Measurements of the length and weight of each shaft are compared for accuracy and consistency against the published specifications listed by the manufacturer. With shaft weight that tolerance is less than 1g.
• Length
Each shaft is measured, in inches, on my calibrated shaft ruler.
• Weight
Each shaft is weighed, in grams, on my calibrated digital swingweight scale.
The remaining tests are looking for consistency of each shaft both against my database of identical shafts I have tested previously and against the other available shafts when building a set.
• MOI
The Moment of Inertia (MOI) is recorded, in kg*cm2, on my calibrated MOI Speedmatch machine.
• Balance Point
The shaft is balanced on a straight edge.
The point at which the shaft balances is marked.
The measurement recorded is the distance of the balance point, in inches, measured from tip of the shaft.
To accurately carry out the final two tests, I first have to identify the FLO planes of the shaft.
FLO stands for Flat Line Oscillation.
I install the butt end of the uncut shaft in a 5” clamp on my Frequency Machine.
I attach a weighted laser pointer to the tip end of the shaft to locate the FLO planes of each shaft.
- FLO plane with the higher frequency (S-FLO)
- FLO plane with the lower frequency (N-FLO)
Analysing these readings obtains the final two measurements.
• Frequency
The higher frequency, measured in Hertz (Hz), of the FLO planes measured is recorded as the frequency of the shaft.
• Radial Integrity
The percentage difference between the higher and lower frequency readings of the two FLO planes of the shaft.
For each shaft that passes all of these checks, I complete an additional series of measurements.
Load Profiling
Using a NeuFinder 4 (NF4.1) digital deflection board, the load of the shaft is measured in KG at 2” increments from the longest beam length at the butt end to the shortest beam length at the tip.
The FLO plane with the higher frequency (S-FLO) is orientated 12-6 for the load profiling.
Each measurement is carried out and repeated to a precision of 0.01kg.
From these load measurements a graph is produced showing the load profile of the shaft.
The load profile is inspected for a smooth increase in load reading from butt to tip. A soft spot or defect will show up as an unusually high or low reading compared to the adjacent load profile readings.
When comparing a set of iron shafts, the profiles are overlaid to identify if any of the readings from any of the shafts are inconsistent with the others in the set.
Shaft Certification
Every measurement from each shaft is recorded on your Shaft Certification document and is provided to you with every build as part of the Blueprinting process.