RE: ShopTalk: Frequency meters and deflection boards

[Bruce Tunnicliffe]

Don’t use lead tape! That will increase the weight and lower the frequency. Use Aluminium foil, or a piece of white electricians tape.   Another thing that is very important is to make sure the clamped end stays still. A small vice that is not securely bolted to a solid bench, that shakes as the club is twanged, will also reduce the frequency. It effectively is saying the shaft is not clamped at the point it enters the clamp, but “back a bit”, where a “bit” depends on how close to motionless the vice is.  Note that mounting it on a lightweight table that also shakes, will lower the readings too.   Bruce   -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] On Behalf Of Royce Engler Sent: Wednesday, February 05, 2003 9:50 PM To: [EMAIL PROTECTED] Subject: RE: ShopTalk: Frequency meters and deflection boards   I've had a Brunswick freq analyzer for several years...one of the early things I learned was the effect of clamping on frequency.  When I bought it, I also bought a calibration shaft, and it turns out that what you actually do to calibrate the machine is change the clamping location.  Sooooo  as it turns out, the correct clamp length for my **system** (and I'll elaborate on that a little more in a minute) turns out to be about 4".   I mentioned the clamping "system"....here's what that includes:  The base of the machine has a v shaped slot that the grip is clamped into (you have to measure shafts with grips on them...I have a whole drawer full of split grips).  The shaft is clamped by a plate with one end resting on the base, and the other has a v-shaped slot that matches the one on the base.  The clamping force is applied by a screw type mechanism with a slip arrangement that allows the handle to slip when it reaches a certain torque (I have no idea what that quantity is, but the instructions say to turn it until you get three clicks.  This is similar to the clamp knobs on the Golfsmith FA.   One day I noticed that the clamp arrangement was squeaking, and like any good engineer, I took it apart and greased it.  Lo and behold, suddenly my frequencies jumped.  I "recalibrated" and found that I needed to shorten the clamping length to get the same frequency.  What had happened was that by lubricating the clamp, I enabled it to get tighter before the torque limiters started slipping, thus the clamp pressure had increased, resulting in an increase in measured frequency.   Enter the PCS Equalizer...The way the Equalizer works is that it measures a shaft against an arbitrary standard and assigns a frequency to it.  You then measure the frequency of that shaft in your machine, and compare the measured frequency with the standard frequency to get a conversion factor.  That conversion factor then generates a set of curves similar to the FM precision curves, but calibrated to your freq analyzer, clamping system, and all.  Soooo.....   The bottom line is that if I wanted to, I could make a shaft read in a wide range of frequencies, all of which would be correct for the configuration of clamping length, pressure, and grip.  The key is to get a good comparison standard and try to be as consistent as possible in how you clamp the shaft.   Having said that, I do notice that sometimes the electronics get fooled by a dark colored shaft.  I noticed that sometimes a black graphite shaft would read quite a bit lower than others.  What I figured out was that the electric eye that counts the times the shaft goes by it couldn't always "see" the shaft and missed counts, which leads to a lower indicated frequency.  Solution is to keep some strips of lead tape handy and wrap the shaft where it is in the path of the sensor.  Also helps to have a good strong light behind you pointing toward the sensor.  Steel shafts reflect light better, so they don't seem to suffer from the problem.   Sorry for the long note, but hopefully it is useful to someone.   Royce  -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, February 04, 2003 11:13 PM To: [EMAIL PROTECTED] Subject: Re: ShopTalk: Frequency meters and deflection boards Dave   You are correct. That was a very good test. It opened my eyes. The clamping mechanism is more important than the electronic side because it is where all the variable seems to lie. The electronics are pretty well governed by design and components used while the clamping mechanism as well as the bench and its stability are where most of the deviations seem to lie between machines. I for one liked your home made unit because yours broke the CPMs down to less than one. I would like to have one that breaks it down to tenths which I think is overkill but that is just me.  Charlie B