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Posted By: Mike088 piano pin torque measuring - 06/21/13 07:02 PM
Hello,

Over the years many people have asked me to help them look for a used piano. Considering I play the piano and that I've read many piano books such as Larry Fine's books in detail, I feel I can offer them some objective advice and help in choosing a piano. This arrangement has worked out well over the years - mostly just help for friends and relatives when they ask me about pianos.

When I inspect a piano I go through the detailed checklist in Larry Fine's piano book however there is one area of the piano that I am not able to determine and that is the tightness of the tuning pins.

I am not a licenced piano technician however I feel competent with tools and handy work. Is this an area of the piano I should not work with, leaving this specialty to a qualified piano tuning tech or can I at least check the pin torque myself with a piano torque wrench without putting the piano out of tune? If not, I would also need a tuning lever and the proper tuning tips and tools and obviously lots of experience tuning pianos - which I do not have.

Once a friend asked me to go with her to check out an old upright. The first thing I noticed when I checked the overall tuning with my tuning fork was that the entire piano was scaled down a semitone. Relatively, it sounded OK, but the fact that it was all tuned down led me to suspect that perhaps a piano tuner at some point in the past couldn't tighten one of the pins up to the standard pitch and so had to tune the entire piano lower. At that point we just walked away and did not consider the piano because we couldn't take any risk ending up with a piano with possibly loose tuning pins. I just wished I had a piano torque wrench to have checked this with certainty.

Should I buy a piano torque wrench, and if so, could someone recommend a supplier on the west coast in Canada or should I leave the inspection of pin torque up to a qualified piano tech?

If you check pin torque with a piano torque wrench, doesn't that put that string out of tune in which case that string would need to be retuned?

PS I often think I would like to take the Randy Potter piano tech course but I need to think about this carefully because it is quite a commitment.

Mike
Posted By: Silverwood Pianos Re: piano pin torque measuring - 06/21/13 07:23 PM
The problem is not the inch pound torque wrench. These are readily available at many of the tool supplies locally. What you will require is the proper star fitting to go over the tuning pins.

At full pitch the tuning pin is forced to the left until it breaks free of the friction control. That would be your measurement for friction resistance.

Then the string attached to the same tuning pin will have to be pulled back up into tune with the rest of the unison.

Regarding low pitch pianos, it is not always because of loose tuning pins. There are other reasons technicians refuse to pull instrument up to pitch, the primary one being an inability to replace or repair broken wire and strings. Another would be structural failure of some sort; most likely plank separation at the top of the instrument.
Posted By: Jim Frazee Re: piano pin torque measuring - 06/21/13 09:08 PM
Dan,

I've been wondering about whether to take the torque measurement on the first pull, thus overcoming both rust, crud and friction, or whether it would be better to take a second measurement once the first "break" has been done. Thoughts?
Posted By: Silverwood Pianos Re: piano pin torque measuring - 06/21/13 09:51 PM

Always as a general rule Jim I test each tuning pin I pick twice. Usually I do all of the C’s or all of the A’s....

This reveals the weakness and strengths of all areas of the block.
I never pull the string up to test the torque. Always to the left, (down). With the string at A440 trying to pull the tuning pin out of place, the pin should hold a minimum of 60 inch pounds of friction resistance including the weight of the piece of wire.

Good question.
Posted By: Steve Cohen Re: piano pin torque measuring - 06/21/13 11:00 PM
Originally Posted by Silverwood Pianos

Always as a general rule Jim I test each tuning pin I pick twice. Usually I do all of the C’s or all of the A’s....

This reveals the weakness and strengths of all areas of the block.
I never pull the string up to test the torque. Always to the left, (down). With the string at A440 trying to pull the tuning pin out of place, the pin should hold a minimum of 60 inch pounds of friction resistance including the weight of the piece of wire.

Good question.


That is exactly the way I was taught. (Back in the old days!)
Posted By: Rickster Re: piano pin torque measuring - 06/21/13 11:09 PM
Excellent information on checking tuning pin torque!

I must confess that I have never checked the tuning pin torque on any used piano I've ever purchased. I figure if it is not outrageously out of tune, having not been tuned in a while, or a particular note is not way out in left field compared to the others, it is likely ok. I know I took a risk, but it has worked out so far and I’ve been lucky.

I’ve only bought one old upright piano that I wish I had not bought, but it was not because of loose tuning pins. smile

It is best to have a pre-owned prospect piano checked out by a qualified piano tech.

Rick
Posted By: Jim Frazee Re: piano pin torque measuring - 06/22/13 02:21 PM
Thanks a lot, Dan. I've been doing it correctly (mostly by intuition) and I check and record all the C's as well. I normally do this when I'm asked to do an inspection for a purchaser or when I encounter bad pins when I see a piano for the first time as part of my pre-tuning inspection report thumb .
Posted By: beethoven986 Re: piano pin torque measuring - 06/22/13 04:56 PM
Originally Posted by Jim Frazee
Thanks a lot, Dan. I've been doing it correctly (mostly by intuition) and I check and record all the C's as well.



Loose pins tend to show up near the bass/tenor break, first. That's where I usually concentrate my torque checking.
Posted By: Mike088 Re: piano pin torque measuring - 06/26/13 10:14 PM
Thank you Dan, Jim, Steve, Rickster and beethoven986 for your helpful replies and for elaborating on this interesting discussion about pin torque.

Mike
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