Golf Shaft Durability Testing

2007-08-25

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By Skip Pankewich, UST Senior Design Engineer

When searching for the right golf shaft, players consider specifications such as weight, torque, launch angle, and price.  It is taken for granted that the shaft is durable, and will not fail as long as the club is in use.  But UST goes to great lengths to make sure that our customers can enjoy this peace of mind about the shafts they play.  We rigorously test our shaft models to ensure that they will withstand the loads typically seen during the life of a golf shaft.  Of course, there are still some rare occasions of product breakage.  But this usually occurs under unusual circumstances, such as the clubs being closed in the trunk, run over by a cart, or wrapped around an offending tree after a poor shot.  Here is a brief description of some UST's shaft durability tests.

Air cannon test
This test simulates and surpasses the conditions a club will see in actual play.  The test shaft is built into a clubhead and then clamped at the grip.  Golf balls are shot out of a cannon at various locations on the club face.  This all takes place inside a netted frame, to keep the golf balls contained.  The test progresses at ball speeds of 100-140 MPH, and totals over 2500 hits.  Today's large driver heads (over 400cc) typically cannot withstand this test, because the wall thicknesses are too thin.  So this proves to us that the shaft is at least as durable as the head is.
 
Accumulative stress test
This test is a very demanding bending test, and certainly identifies the weakest point of the shaft.  The shaft is mounted in a hosel, and a weight is hung at the butt end of the shaft to determine an appropriate "deflection" for the test.  This deflection is much greater than any deflection that the golf shaft sees during a swing.  The shaft is then mounted in a machine which bends the shaft to this deflection point repeatedly.  The machine repeats the cycle of bend/release until the shaft breaks, or passes 10,000 cycles without failing.

As we are developing new shafts at UST, we subject our prototypes to these tests.  Only after passing these tests, and performing well in our extensive player testing, do we allow the shafts to go to market.  We are then confident that UST golf shafts will provide great performance to our customers.