Until CA treatment became my 1st choice, I drove pins for nearly 4 decades. As I explained to my clients, it's getting the bottom 1/8" of the tuning pin hole to do some work for the first time in the piano's life. And I have always been happy with how the new torque lasted over the years, on any piano. Yes, on a grand you have to pull the action and support the block, but with CA, you'd be pulling an action anyway.
Change in the string deflections at the pin and front bearing ridges, or coil height above the plate? Yes, in a bass section (grand or vertical), you don't get to use very much of the coil height before the string leaving the pin wants to climb up on the coil above it. Again, 1/8" at the bottom of the pin hole is all you need. Coil height above the plate? Not an issue if you're paying attention to what you're doing.
In the frequent situation of a rebuilding drilling a block at 0.250 (or less) and then leaving the pins tall (space under the coils @ 5/16"), after ~10 years, driving the pins is the ONLY solution. Driving pins on a multi-laminate block? Most of these are young enough (the oldest, Baldwin's Amberlight of the '60s) that they haven't loosened up yet. So I can't comment on their behavior.
Shimming tuning pin holes does run the risk of prying fissured block laminations further apart. However, if the best makers use only tight-grain quarter-sawn maple for their blocks and if these will successfully take a restringing with oversize pins, then an oversized tuning pin would be the best choice. The absolute worst would be a strip of sandpaper. Under the pin's mechanical action, the paper disintegrates and what is left are free-floating grains of abrasive, the last thing you want in any block.
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William Ballard RPT
WBPS
Saxtons River VT
802-869-9107
"Our lives contain a thousand springs
and dies if one be gone
Strange that a harp of a thousand strings
should keep in tune so long."
...........Dr. Watts, "The Continental Harmony,1774
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Original Message:
Sent: 01-26-2018 14:30
From: Peter Grey
Subject: Loose tuning pin: order of preference for fixes
Agree with all the above.
The "layer" technique that Scott mentioned works well because the first app seeps into the dry pinblock cracks, etc then solidifies. The next application builds on that and sticks to the first. If needed, the third application will really tighten things up.
Don't be afraid to do it progressively like this. Don't get over enthusiastic. You can actually freeze the pin in there so hard that you will be in fear of breaking it. It happened to me.
Pwg
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Peter Grey
Stratham NH
603-686-2395
pianodoctor57@gmail.com
Original Message:
Sent: 01-25-2018 22:29
From: James Kelly
Subject: Loose tuning pin: order of preference for fixes
I agree that pounding in the pin is not good to do since it changes coil clearance and also string angles. I have found that thin CA inserted in the space around the pin inside the bushing works the best for a few loose pins. Otherwise if you insert a sandpaper sleeve you may as well go up a pin size for all of the effort you expand in getting the coil loose and the pin out of the block
I have treated dozens of pianos of all sizes, makes ages with super thin CA and have had excellent results with no failures. In fact some blocks that had cracks between other tuning pins have responded well and held. I think the secret is always having fresh CA, using good dispensing technique, plenty of light, proper safety equipment and experience. Of course if a block has been doped with dreaded mixes of antifreeze type solution with ethylene glycol or some magic elixir all bets are off.
As I have mentioned in the past it is a good idea to have a torque wrench and do before and after measurements of the A's, C's, and random notes. Feeling good may not be enough - an inch lb torque wrench is a good investment and can help you sell needed pin block treatments
If you have only one or two or even up to seven go with the CA. Remember to follow good safety practices as well- CA is nasty stuff and can cause chemical burns
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James Kelly
Pawleys Island SC
843-325-4357
Original Message:
Sent: 01-25-2018 10:28
From: Scott Cole
Subject: Loose tuning pin: order of preference for fixes
There have been any posts on fixing loose tuning pins. What I'm wondering is the what preferences people have for the order of techniques they try. The piano in question is a small Haddorf grand from 1909. All the pins are original and actually feel quite good except for one, which didn't hold at all--zero friction. It had not been previously pounded in. It was the first wound wire above the bass. I muted off the string and will return to clean, fix the pin, and other services.
I have tried CA on pianos. Usually it works, but sometimes it doesn't. So let's say we have various options: CA, pounding the pin in, installing a larger pin, using a sandpaper sleeve. My question isn't HOW to do these but what your order of preference is. What would you start with, and then what's next if it fails? Is CA always your first choice? If it fails does it cause problems in installing a new pin? (yes, I have the equipment necessary to support the pin block, cover everything for glue drips, etc.)
thanks
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Scott Cole, Registered Piano Technician
Serving Southern Oregon and Northern California
(541)601-9033