RE: ShopTalk: Forged 7075 Aluminum woods

[Dan Neubecker]

David,

 

I once asked Tom Wishon about the idea of air cannon testing of each head in terms of making a claim for better quality.  I don't think Tom would mind if I shared his response (see below).

 

Dan Neubecker
[EMAIL PROTECTED]

 

 

Yes that is possible for sure with many medium size foundries since an air cannon is not that much of a luxury item to have.  But knowing what the ball firing speed is AND very important, knowing how the head is fixtured (nested vs on a shaft hanging free) is a big difference in the testing.  I know this from my experience in having all of the Ti heads I designed in the thin face era (last 3 yrs) that there is a huge difference in how a head takes the stress of a ball shot at any particular speed when the head is secured in a nest so there is no movement in reaction to the impact, compared to if the ball is fired against the face while the head is on a shaft and the shaft is what is secured.  Point being, when the head is secure nested a ball that hits the face at 125mph is really putting the equivalent stress on the face of a ball that is fired at about 150mph, since the head cannot move and there is no dissipation of the impact from the head being able to rebound back in response to that impact.  Therefore, any head that is safely tested at 125mph ball firing speed in an air cannon test could really have been made with a thinner face if what the company wanted was the maximum face deflection short of failure - hence, the version of the test while on a shaft with the head non-supported in the rear is going to be more of a depiction of real swinging impact. 

Also, and this is one that is a real biggie in any type of test for durability - yes it is great to do the air cannon testing to weed out the poor welding jobs primarily.  But air cannon testing on real production can actually do damage to the head that is not ever known and which will shorten its life unless the heads are all x-ray analyzed after the air cannon test - and I can assure you that not even Callaway with their money they spend on head production pay for something like that.  So what I am saying is that it is not all that uncommon for any head that is air cannon tested to then break at some point down the road when put into play by the consumer - and you never have a way in this case of knowing if that failure could happen in the first week or never.  And now you can see why air cannon testing when the head is secure nested can actually be bad for the production heads destined all to be sold to consumers. 

While I will still always use air cannon testing as a way to dial out the bad weld jobs, I really do not like to do it on the heads you are selling using the nested head form of the test, nor at a speed that is much over 125mph.  Where you want to do your real destruct testing is on a random sampling of heads made in PRECISELY THE SAME WAY that is being used in your production where you know all the variables on the test heads before the destruct tests are done - all variables being face raw material mechanical properties, heat treatment results on the mech props, loft, bulge/roll and the actual real face thickness.  This way what you then do in production is try to focus your energies on making sure that the delivery of the raw material is always within a tight tolerance, the heat treatment is within a tight tolerance, the loft, bulge/roll and face thickness are too.  And then the air cannon becomes only for the welding check to get the ones that had bad welding out of the pile and is only done on your heads for sale at a speed that is in the real world, so that it cannot have as much of a chance of doing real damage that would result in failure down the road.

 

 

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, November 13, 2002 12:01 AM
To: [EMAIL PROTECTED]
Subject: ShopTalk: Forged 7075 Aluminum woods

Hi All,
Does anybody know any thing about forged 7075 Al?
I've been offered these at a good price and the heads look very nice and are in the 400-500cc range.
Supposedly the benefits are that they are stronger than "traditional die cast 356 Al" which allows for a larger head and a thinner face and a mirror finish which die casting does not, due to too many pin holes.
They claim that there will be no problems with breakage as each PC will be air cannon tested.
David