[pianotech] Hybrid Pinblocks

[Jim Busby]

Hi Joe,

Me too. And, after 6 months I found that the torques remain close to the same WITH the driving fluid, in a hybrid block. In the same test w/o driving fluid I found torques went down after 6 months. That's as long as I've had the test going. Also, I found that some pins with fluid "jerked" the first few days but didn't after that. Folks should know about the jerking pins because the first time I think I cussed you <G>, but you haven't failed me yet!

I think it was you that got me to using driving fluid and have used it for about 6 years or so. Love it!

Regards,
Jim Busby

(p.s. I didn't quantify how much torque because my wrench is an older POS)

From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] On Behalf Of Joseph Garrett
Sent: Thursday, February 18, 2010 1:44 PM
To: pianotech
Subject: Re: [pianotech] Hybrid Pinblocks

Ron said: "Another thing: I've noticed that pin
torques two or three days after stringing feel higher than
when you're installing them. This may be a body calibration
illusion relative to the different levels of violence imparted
whether stringing or tuning, and I've never taken actual
measurements, but it's worth a look. How do those test piece
torques match up today?"

Ron,
I have taken the torque data while testing various Pin Driving Fluids. I noticed the same phenomena.
Torque readings taken at stringing time; a day later; a week later and a month later. On day the torque would be lower than a day or week. After a few weeks, and several chip tunings, etc., the torque readings kinda came back to the original on stringing day, but just slightly higher than the originals. Go figger! This was the case for several different PDF.
As for the remark about the Rosin used as a Pin Driving Fluid, I tried it once. Definately not what I was striving for. The idea of the PDF is to lessen the trauma to the drilled hole when we drive the threaded tuning pin into it. What is does is make the wood fibers slippery and more pliant during the driving. This reduces the amount of chaffe due to the threads. I believe it also tends to seal the drilled hole somewhat. I have done studies with and without and have found that it also reduces the initial torque by about 20%, but only initially. I still have some test blocks laying around, (I don't throw anything away.<G>) Hmm? best get them out and see how the torques are holding up after several years.<G>


Joe Garrett, R.P.T. (Oregon)
Captain, Tool Police
Squares R I


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