Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Using varnish when restringing

Yep, instead of driving fluid, some of the laminates like delignit could do with a swabbing of acetone when they are done.

Keith,

You speak of driving fluid as something that "dissipates". I presume by this you mean that it is volatile and doesn't leave any solid residues. And yet, you mention sanding sealer or shellac as driving fluids. Both these contain solids dissolved in a solvent carrier. (Just as varnish does.) The solids don't "dissipate".

Could you explain what you mean by a "dissipating" driving fluid? Perhaps a very dilute coating?

People may put other things (or nothing) into tuning pin holes, but the purpose of a driving fluid is simply to lubricate the tuning pin during the time that the pin is actively being manipulated during the stringing process. Any permanent residue is merely incidental -- or perhaps providing an additional benefit.

Varnishes are slow drying and have a high solids content. As a general category, their films also tend to be softer and more flexible than lacquers or shellac. In other words, a potential for a more "gummy" kind of end result. I am not aware of any studies comparing varnish and other products as a driving fluid, but its properties are welll-known and that would be my assumption about using varnish.

You are right, of course, that there is "something" left behind -- otherwise why not just use whatever thinner is the vehicle for the finish? But lacquers --as a category including sealers-- (followed by shellac dissolved in alcohol) is recognized for both for its low viscosity and its volatility; particularly in comparison to varnishes.

The effects of these two qualities is recognized by refinishers: If you apply lacquer sealer or shellac to the end grain of wood, it will be observed to
1) soak into the wood with little residue evident on the surface, and
2) dry very quickly.
In comparison, varnish will leave somewhat more of a film and take longer to dry.
There is no reason to suppose that the variation of those qualities between the lacquer-type category and the varnish category changes merely because it is happening inside a tuning pin hole.

In practice, the use of a driving fluid (I use lacquer sanding sealer and a few mililiters will do an entire piano) does lubricate the pin hole for a few hours, with the greatest effect within the first 20 minutes. As I mentioned, earlier, it also does seem to make for a nice "feel" as well as a higher final torque, so no doubt there is some effect of the solids component remaining in the hole, but it is not the primary reason for using the fluid.

As has been pointed out, there are other parameters to consider when drilling blocks and I don't suggest that driving fluid will somehow magically fix some major blunder done in another part of the process.

Having done it with and without driving fluid, I can say I prefer the use of the driving fluid. However, I don't suggest it is essential and realize that there are multiple approaches to doing high quality work. It may be that those other approaches involve a higher risk of carpal tunnel syndrome and the like . . .

'Interesting thread. I've used Delignit material since 1978 (if memory serves). Initially I tried many different combinations of drill sizes, drills, several varnishes, powdered rosin, nothing on the pins, and even pointing the pins to all four points of the compass before driving. Tentatively, I finally settled on something that seemed to yield the most consistent results with a twenty five year track record - careful and consistent drilling with a cold air stream on a really good letter size "H" fast spiral drill. I use powdered rosin on the pins, but that may be a little bow to voodoo hoodoo.

Now I get to start all over experimenting with a Boulduc block. Yippie!

If you are going to try a new block, I recommend the Falconwood -- now sold by technicians based in Milwaukee. It's a stronger block with a higher friction ratio than any other block -- thereby requiring less stress on the block to maintain a given torque -- and there has never been a failure since its introduction about 50 years ago.

For Falconwood, you only need an "I" drill bit using your same drilling protocol.
I use driving fluid.

Going for a new block I would recommend the hybrid, designed by Ron Nossaman.
A custom 9mm Dilignit cap (not bridge capping or pin block material) on a standard multi-lam block.

My rebuilder has been using the Falconwood pin block exclusively for many years, with not one failure. I have one in my M&H RBB.

He did mention to me once, that it was important to use a new drill bit with each pinblock....I suspect this is the case when drilling any pinblock?

I bore twice, taking out about 1/2 the wood with the first bore using a bit I can sacrifice, and then boring to final diameter. Heat builds up when the chips cannot escape faster than they are generated, so taking out a bunch of wood first keeps the second bit from overheating, and it can be reused several times with only a bit of honing.

I've found rigging up a stream of compressed air on the bit while drilling keeps it cool. I use even pressure on the bit, so I progress faster in softer areas of the block and slower in harder areas. I've never used a driving fluid - dry pins have been fine. I keep my fingers off the threads of the tuning pins, so no issue there - (I use a string coiler). The only issue with sticky pins I've had was this old Lester grand, where budget forced me to keep the same pin block. The old, loose pins were sticky, and the new, larger pins were just as sticky.

I wonder if some of those lovely feeling Indonesian and Chinese blocks are varnished up during stringing. My restrings don't feel like those do - never have.......

Another consideration is ambient RH when drilling. If the RH is 20% due to cold winter air, a good feeling block can be way too tight when it gets to humid Florida where the average RH is 55%. Dealing with tight pins is common here.

I agree about two passes. The second will get rid of any errors made on the first.

I once re-drilled an existing block for oversized pins. I ground off the cutting edge of the bit, let it pull itself into the hole, held it in place and spun the drill to let the flutes do the cutting. It came out ok.

Years ago when I bought a new drill press I checked the runout and wasn't satisfied with the little swirl the drill point was making. I showed it to a neighbor who was a machinist with the comment that I was thinking about returning the heavy thing. He offered to clean the morse taper and that solved the problem, but it wasn't just a wipe and swipe cleaning. He cleaned the seat and the taper repeatedly with alternating applications of lighter fluid and light oil ending with oil that he wiped off completely. He said the the factory workers had filings on their hands and gloves and that they hardly ever got the tapers really clean.

David the problem of contaminated taper seats in machinery is one that is carefully avoided in better manufacturing companies. When I worked for Magna for example, no air hoses were allowed near the spindle for cleaning or during a tool change operation. Softer metal chips like brass/bronze/aluminum/CRS have a tendency to stick to the harder shanks and tapers when driven against each other.

Too many folks don't fully understand the cost involved in making super high quality tools, even things like simple drill bits. My complete letter/number drill bit set manufactured by Sheffield cost over $500 20 years ago. The same assortment of bits can also be bought for $49 from china, or for any cost in between by other manufacturers. My bits were used every day for numerous years, drilling alloy steels and materials much tougher than wood and they still work like the day i got them, provided that they are sharpened correctly when needed. If one needs to purchase a new bit after drilling one or even a dozen pin blocks, you have an inferior tool to begin with.

Gene, what is the difference between Delignit pin block and bridge cap material and the pin block capping stock? Does it have a specific name?

Jurgen, it appears that there may be more laminations than the bridge capping material, I count 7 on this 9mm cap but I do not have any other Dilignit material here to compare.
If memory serves, Ron has specified what he wants and Dilignit makes it for him, so there may be more to it than just laminations.

David: Now if only the tuning pin manufacturers would true up their tooling the way that you do we would not be forced to deal with tuning pins that vary in diameter by several thousandths or that are oblong.

Speaking from a bit of experience, I can't see one person being able to order enough to come anywhere near a minimum factory order. They usually ask if you want a twenty foot or a forty foot container full. The material must be available somewhere.

I have found that Diamond or Bienne pins have less of this symptom. One of those brands used to be Fly Brand but I can’t recall which one.

I have heard that the Japanese tuning pin manufacturing has been sub-contracted to India. Anyone know anything about this?

Jurgen, the only pins I know of with the Japanese-Indian connection is the Nippon Denro which is presently owned and run by Ispat Industries. I believe Hitachi originally set them up with the steel rolling process and another large Japanese firm collaberated but that was over 20 years ago. I still see numerous suppliers of the Nippon Denro pins in the U.S. state in their advertising "Manufactured in Japan". although the pin quality is decent (ie. not great). I highly doubt the Indians are subcontracting out to Japan for something like this. I've used them for years in anything but a really high quality piano.

I always felt that Denro pins had too much twist.

Jurgen, I trust your experinece and I trust Ron, however I do not know much about Ron's business.
For what it is worth, I measured the laminations on Dilignit block material at 8 in 9mm and Ron's capping material at 7 in 9mm.
Maybe somebody out there has some Dilignit bridge capping material that they can measure?