Re: ShopTalk: swingweight

[Lloyd Hackman]

Arnie   Unless you are saying that the statement "Understand that a graphite shaft spreads bending force over a larger range of the shaft length" refers only to the stress concentration area you still have not addressed the question. If this is what you are trying to say in this statement, spreading it out over a wider area is good but not true. Epoxy alone on the inside of the shaft or outside of the shaft is not hard enough to cause a significant stress concentration since the shaft its self is epoxy. The real culprit in this whole thing is that graphite fiber is a very brittle material and can stand little if any stress concentration. If coning helps in the Hosel then tapering the end of the weight insert should do the same thing.   llhack   ----- Original Message ----- From: To: ShopTalk@mail.msen.com Sent: 10/17/2005 10:34:37 PM Subject: Re: ShopTalk: swingweight In a message dated 10/17/05 12:05:30 P.M. Eastern Daylight Time, [EMAIL PROTECTED] writes: Are you saying that what you wrote "Understand that a graphite shaft spreads bending force over a larger range of the shaft length" is not right. Or what did you want us to understand. Let me try again. If you concentrate the "breaking" point (top edge of hosel) by filling the tip with epoxy or a shaft pin weight you are concentrating the breaking weak point in one area (the top edge of the hosel). This is the reasoning behind not filling a graphite shaft tip with epoxy. By reinforcing the tip this way you allow the stress point to be concentrated. Steel shafts can handle this treatment, graphite shafts cannot. I have tried to explain this with the examples of breaking a stick over your knee. The "knee" is the top edge of the hosel. "Padding" this area with a coned/epoxy fill plus a ferrule helps prevent breaking. Filling the shaft tip with epoxy or an epoxy secured  pin just is not a good practice. If you cushion the pin with a masking tape wrap to prevent a pin buzz or rattle is OK. the pin usually has a head so that it cannot be allowed to slide up into the shaft and the head of the pin can be secured with a very small amount of epoxy during the normal shafting. All I can add is that most broken graphite break at the very top of the hosel and in most cases the shaft tip has been filled with epoxy to the top or very near to the top of the hosel. Shaft rattles are most often the result of this epoxy "rod" breaking free of the inner shaft wall, this being caused by poor bonding to the inner shaft wall due to the presence of the releasing agent. This is rare in steel shafts but it does happen.