At 08:32 AM 2/5/03 -0600, Donald Johnson wrote:
Dave:
Have another question vs. clamping Most of the units sold for
Clubmaker's have a grip clamp designed like a vise clamp so the shaft is
contained almost 360 deg at the edge of the clamp making the beam length
pretty consistent. However at least 1 of the production model's I've
seen was 2 v supports 3/8" thick 5" apart with a third pneumatic support
from the top about 2 1/2" from the either end. The shaft was held by
only a small spot on the bottom of the front v grove. This to me would
make for a varying beam length.
Let's label distance along the shaft in inches, with zero inches starting at the butt. This clamp consists of three V-blocks; they are short, each contacting the shaft for only 3/8" of the shafts length. The blocks touch the shaft at:
* 0 inches, from below.
* 2.5 inches, from above.
(This is the driven member; the other two are stationary.)
* 5 inches, from below.
That would appear to allow a little flex to go on between the clamp members. It would not be much, since the butt is the stiffest part of the shaft. But it would lower the frequency. Without going through more analysis than I want to this morning, I couldn't say whether the error would be more like 1/2cpm or 10cpm.
That might explain something. But I'd be surprised if the error was more than 10cpm, and the differences we've been seeing are more than 10cpm IIRC. Also, I don't remember whether we've been seeing higher or lower frequencies than SK reports; this explains it only if we see higher frequencies.The reason I ask is this was a device SK Fiber used and it seems folks had a hard time duplicating SK's published numbers.
Cheers!
DaveT
PS - John, is anything holding up the posting of my Frequency Meter article? I have photos there of my clamp, which consists of V-blocks that don't wrap around the grip 360*. But they are a solid 5" long.
