Dave:
You are correct in you interpretation of what I was trying to
describe. My guess would be the numbers you would get from this type of
clamp would be lower as the apparent beam length would be longer. So a
Digiflex type clamp would tend to give higher numbers.
Don Johnson
-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
On Behalf Of Dave Tutelman
Sent: Wednesday, February 05, 2003 10:02 AM
To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
Subject: RE: ShopTalk: Frequency meters and deflection boards
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.
I'm not sure I visualize this, so let me paraphrase what you said.
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.
>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.
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.
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.
