Very interesting! I was looking at a similar setup a couple of years back to see if I could find a relationship between shaft butt torque and tip displacement. I used a three bearing spine finder I rigged up at home. There were two bearing about 6" apart at the butt. A small bearing at the tip was used to get shaft deflection without inhibiting rotation of the shaft.
I measured torque produced at the butt for a given tip deflection using a 400 gram scale. I clamped an arm about a foot long near the shaft butt. The tip of the arm was bent to a right angle and contacted the pan of the scale. After zeroing the scale to cancel out the weight of the arm I pulled the tip downward several inches. The torque produced by the arm on the scale was very small. I don't remember the exact number but I was surprised because when keeping the butt from rotating with my fingers led to expect a lot larger number. My thought was that such a small torque would cause much less than a degree of clubhead rotation for shafts having only 3 or 4 degrees manufactures rating. My next thought was that maybe I had looked at this from the wrong end. The action is most likely reversible even though the mechanical advantage is low. What would happen if I would torque the butt of the club while keeping the tip from rotating but allowing it to deflect? This might be one of the causes of variations in impact location on the clubhead face. Never have figured out an easy way to make the measurement. LOL DeanS ----- Original Message ----- From: "dbMiko" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Saturday, October 11, 2003 8:17 PM Subject: Re: ShopTalk: N-S Plane vs. Severe Wobbler > Dave Tutelman wrote: > > At 03:25 AM 10/11/03 +0000, golf54com wrote: > > > <<lots o' snippage>> > > >The straightness gauge I built for him also has a > > load cell with a zero-tare button, so it could be used for the purpose. > > But my load cell feature was an afterthought, > > Dave; > > 1) Where did the load cell come from? > > 2) Where is it located on the "straightness > gauge"? > > > I ask because I'm playing with my own variant of > the nuefinider(sp?) -- where I use the load cell > from a digital postal scale to measure the > torsional load about an axis 4" from the butt end > of the shaft for a given shaft tip displacement. > > The intent is to measure the torque required to > load the shaft a given amount- (4" for 43 1/2" > Driver) ... > > I'm expecting to get a sense of what the hands > feel with different types and styles of shafts. > The hands are, after all, the only contact we have > with the club, and it's what the hands do, that > ultimately determines how the club will perform. > > My 2 kg postal scale isn't quite what is required, > something more in the 10 kg is required, but > digital scales in that range start getting > expensive, and it may be worth while to go the > load cell + DVM route to get exactly what I want ... > > Any info, of course, is quite helpful, > > Thanks, > miko > > >
