Putter Torque Measurement

Axis 1 – Putter Torque Measurement
Tests conducted on 26 September 2009
27 September 2009
Background and Purpose:
Axis1, LLC has developed and is currently marketing an innovative golf putter, which has very low
static torque about the axis of the putter shaft. Axis1 wanted a simple, inexpensive, and
repeatable method of quantifying this putter torque for their putters and those of their
competitors’. Furthermore, the apparatus to perform the measurement was to be easily
replicated.
Experimental Hardware:
The following components and hardware were required for the testing:
Generic Hardware Description
Test platform
Clamp with arm with repeatable contact point
Dial or digital calipers
Digital scale (minimum resolution = 1 gram)
Square
Spacer, as necessary
Putter shaft with grip or Ø.415 (10.5 mm) shaft
Specific Hardware Description
See Appendix A for details
See Appendix B for details
Mitutoyo CD-6” CS Digital Calipers
Salter – Model 1010
Swanson TS151
.450” stack
Putter shaft with grip
Putter shaft with
grip
Clamp with arm
with repeatable
contact point
Spacer
Digital scale
Apparatus in Calibration Configuration
Test platform
Procedure:
Apparatus set up and calibration
1. Place the platform on a solid and level surface.
2. Adjust the test platform feet such that the platform is level, as indicated by the bubble levels
on the platform.
3. Place the digital scale on the test platform and turn on. Ensure that the digital scale is set to
read in grams.
4. Apply the clamp to the putter shaft and handle, at a point where the shaft diameter is ø.415”
(10.5 mm). Place the shaft on the test platform support rollers. Determine the height of
spacer between the clamp tip and digital scale surface to make the clamp shaft horizontal.
5. Measure the distance between the shaft diameter and the clamp contact point. Measure the
thickness of the clamp contact point. Calculate the nominal contact radius. Note that this will
not change for a give clamp and does not need to be measured each time the clamp is used.
Axis1 Putter Torque Measurement
27 September 2009
6. Remove contact between the clamp arm and spacer, and tare the scale. This will eliminate
the effect of the weight of the spacer from the torque measurements.
7. Bring the clamp contact point into contact with the spacer. Record the value. This is the
torque associated with the clamp, which will be subtracted from the subsequent
measurements on actual putters.
Putter testing
8. Apply the clamp loosely to the putter being tested, at a point where the shaft diameter is
ø.415” (10.5 mm). Place the shaft on the test platform rollers, such that the clamp tip is on
the spacer stack.
9. Using the right angle rotate the putter face such that it is above the shaft and perpendicular to
the ground. Ensuring the clamp tip is in contact with the spacer stack, tighten the clamp.
Once the clamp is tightened, ensure that the putter face is still perpendicular to the ground.
Clamp contact
point in contact
with spacer
Putter visually
confirmed as
perpendicular to
ground
Confirming putter is perpendicular to ground
10. Move the square away from putter. Lift the clamp tip off of the spacer. If the value is not
zero, re-tare the scale.
11. Bring the clamp tip into contact with the space stack. Record the value.
12. Repeat Steps 8-11 twice for a total of three times.
13. Repeat Steps 8-12 for each putter to be evaluated.
Calculate putter static torque
14. For each putter average the measured force.
15. Subtract the bias force measured in Step 7. This yields the average force at the clamp
contact point.
16. Multiply the resulting average force by the contact radius. This is the static torque of the
putter in the horizontal position.
17. Adjust the resulting static torque to compensate for the fact that the average putter is used at
about 20º from vertical compared to the test which is conducted at 90º from vertical. This is
accomplished by multiplying the previous calculation by sin(20º) or .34.
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Axis1 Putter Torque Measurement
27 September 2009
Results:
1. Tabulated below are the measurements taken on the clamp, when applied at ø.415” (10.5
mm) on the putter shaft:
Dimension
From outside of shaft to outside of contact point (W)
Shaft diameter (D)
Contact point thickness (t)
Value
127.0 mm
10.5 mm
1.2 mm
Moment arm (W-[D+t)/2])
121.2 mm
2. The bias force associated with the clamp on the putter shaft alone measured 16 grams.
3. Tabulated below are the results of the measurements on the Axis1 Eagle and a number of
other sample putters.
Test (grams)
Putter
Axis1 Eagle 35"
Ping PAL2 36"
Odyssey 6600 35"
Odyssey White Hot XG 2 ball 34"
#1
16
40
61
108
#2
15
39
59
107
#3
15
38
59
108
Avg.
(grams)
15
39
60
108
Minus
Clamp
Arm
Bias
(grams)
-1
23
44
92
Avg.
Torque
(g-cm)
-12
278
532
1113
Adjusted
Avg.
Torque
(g-cm)
-4
95
182
381
Conclusions:
1. Without characterizing friction in the support bearings, variances in how the putters are setup, accuracy of the digital scale, and other sources of variance, it is clear that there are
significant differences in the static torque between putters. The Odyssey White Hot XG 2 ball
has a static axis torque that is two orders of magnitude greater than the Axis1 Eagle.
2. The apparatus and test protocol as currently designed are adequate to demonstrate the
significant differences between the putters. Depending on the goals of future work,
refinements could include:
• Mechanism to ensure that putter shaft is perfectly horizontal. As presently designed, the
shaft could be slightly angled downward by .25º, which might reduce the measured
torque by .5%.
• Balanced clamping mechanism which can be applied anywhere on the putter shaft.
• A more precise, calibrated digital scale.
• A larger sampling of putters of a single type.
• Lower friction and better characterized support bearings.
• Easier method of squaring the putter. As currently configured, this requires two people to
accomplish the alignment.
• Arrange the device to measure the torque at the natural position of the putter.
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Axis1 Putter Torque Measurement
27 September 2009
Appendix A: Test Platform Design
The design of the test platform is intended to be simple and inexpensive, with most components
being readily available from a hardware store. As currently implemented, the following
components were used to for this assembly:
•
•
•
•
•
•
•
Two axis bubble level
2x cabinet latches (these are the support bearings)
24” x 11.25” x .75” thick oak board
16” x 1.5” x 1.5” oak board
3x 2” x 1.5” x 1.5” oak feet
3x pressed in adjustable feet
Wood glue
2x cabinet latches
16” x 1.5” x 1.5” oak
board
Clamp contact
point in contact
with spacer
Top view of test platform
24” x 11.25” x .75”
thick oak board
3x 2” x 1.5” x 1.5”
oak feet
3x Pressed in
adjustable feet
Side view of test platform
While any number of configurations would be effective, there are a number of key features which
are important. The test platform must have:
• A means of leveling the primary surface.
• A low friction support of the putter shaft, such as the cabinet latches with rollers.
• An adequately large flat surface to allow moving the digital scale to adjust for the position
of the clamp on the putter shaft.
• Shaft supports that are adequately far apart to keep the putter shaft very close to
horizontal despite the typically decreasing shaft diameter more distally to the grip. In this
case the supports are 16.5” apart center to center.
• Shaft supports that are at the same height to ensure that the putter is close to horizontal.
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Axis1 Putter Torque Measurement
27 September 2009
Appendix B: Clamp with arm with repeatable contact point
The following were used in the assembly of the clamp are with repeatable contact point:
• Clamp, McMaster Carr part number 20625A212
• #10 Flat Washer (ø.5” x .047” thick nominal)
• Epoxy
Clamp
#10 Flat Washer
epoxied to tip of
rod. This serves
as the contact
point.
Clamp with arm with repeatable contact point
The exact configuration of the clamp is not critical, with the exception of the following details:
• The contact point should be relatively small to ensure repeatable force measurements
and well defined moment arm radius.
• The resulting contact point should be between 4” and 6” (100-150 mm) from the center of
the shaft. This will ensure that magnitude of the contact forces is
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