RE:Lubricating Strings at Bearing Points
Registered Piano Technician
Wherever strings and metal bearings dull over time, lubrication should help. Dull = oxidized = greater friction = greater wear. So, by lubricating the bearings not only do strings render more responsively, but may eat less into the bearings. I don't have proof for this, but I picture a slick string cutting into the V bar less than an abrasive cord.
I'll never forget the first time I lubricated the front bearings in a piano with particularly poor string rendering. The strings had been binding terribly and felt "stretchy," but suddenly they were rendering smoothly and responding normally. The improvement was dramatic, and I started lubricating bearings in almost all pianos I tune. Tunings have been much more pleasant and take less time. I've had very few broken strings since.
A lubrication can last several tunings, so you don't have to do it every time--string rendering will tell you. I find it especially important to lubricate counterbearing felts. Vacuum them first.
I focus on the V bar, counterbearing or pressure bar, and counterbearing felts. So far as applying the lubricant at bridge pins, I do it mostly in grands with oxidized strings that need a pitch raise. I'll apply CLP or Prolube with a moist but not dripping felt wedge from mid-tenor up, dabbing the wedge onto the strings from the speaking length side against the front bridge pins. I'll do the same from the rear duplex against the rear pins. I've looked at the pins with a magnifier and don't see the lubricant dripping or flowing into the wood. If it does, it does so in very small quantities, certainly much less than when applied to center pin bushings, and I haven't observed an appreciable change in the wood of hammer shanks and wippens treated with CLP. I haven't observed any increase in false beats or issues of any kind related to bridge pins or bridge caps. If someone has, I'd like to know.
Someone else in this thread said they apply the CLP with a hypo needle applicator. That seems a bit risky as those tiny drops have a way of leaving the needle when you least need them to. A felt wedge is my preferred medium. The only downside is that it gets dirty, but it can be washed with alcohol.
I place a mover's blanket and/or drop cloth next to the piano (I often put the bench on the blanket) and apply the lubricant to the tip of the felt wedge with a hypo oiler over the cloth. If the wedge is dry, I saturate the felt, and excess gets wicked away. While I have most of the lubricant concentrated at the tip, I'll insert the tip between the dampers and the capo bar, and dab where the strings meet the V car. Next, I'll do the same from the other side, then in the upper treble section, and then dab against the agraffes from both sides. Careful not to get close to the coils on bass strings or tuning pins. In verticals I dab where the strings meet the pressure bar except where tuning pins are so close to the pressure bar that the lubricant might get onto them. Next, I'll rub the strings over the counterbearings and felts. This is where I reapply the lubricant to the wedge more frequently. I store the wedge in a closable lunch bag and douse it with alocohol to clean the dirt it picks up.
Hope this helps and thank you for your interest in the book.
I was very impressed by this posting of Mario Igrec in Pianotech. I applied CLP to all bearing points including the tuning tabs in the front and rear duplexes on my piano. Pulling the action allowed direct easy access to the bottom of the capo bar following Mario’s technique above. Virtually all noticeable, in tuning bearing friction was eliminated. The tuning also was easier and faster.