Piano World Home Page Forums Our Most Popular Forums Piano Tuner-Technicians Forum Open face pinblocks rock

The discussion in the Petrof thread inspired this one. I routinely service many old uprights with open faced blocks here, and every single one of them still feels great. Nice feel, nice and stable. Don't know if it's coincidence or not, but through the years it seems like the open designs have held up much better through the years.

One advantage I see is that the coils are much closer to the block with the absence of the plate there. I believe it makes a firmer and more reliable anchor. Anyway, just my .02!

Good Topic.

I also like the feel of open face blocks and I suspect they hold up better. Here is why: leverage! The further the becket is from the block, the more force the block must hold up against.

I remember an odd problem with a Baldwin Studio. A plate bushing was missing. The pin hung down due to the string's force and did not have enough torque to hold pitch. I put in a bushing and it was then OK. The block was not up to the task with the leverage involved.

And then there is the added length of pin that twists and untwists as you tune. The less there is, the less you have to deal with.

There is also between 25 and 30% more tuning pin (thread) in contact with the pin block. This means that the pin will potentially maintain its torque for a longer time/more tunings.

Have you ever noticed that blued tuning pins seem to hold better and tune better and have less loose tuning pins than the nickle plated ones?

I have encountered some open-face pin blocks with short tuning pins.

The new Yamaha CF4 and CF6 have open blocks too.

I'm wondering: if there are so many evident advantages to an open-face pinblock, why has a closed face (be it with or without plate bushings) essentially become the industry norm? I would think that a closed-face design is actually more intricate to manufacture?

Very good question, Mark. I'm guessing it's a strength issue in regards to the plate, but I could be wrong. Del would be a good one to offer input on that.

Del?

Beautiful pic! I love the look of pins going directly into the wood. I still say they feel better when tuning than through-the-plate pins.

The full cast iron plate might have been like the middle pedal. No one would buy a piano without one.

Ha! Good one, Jeff. Don't you just love when you encounter one of those "dummy" middle pedals that does nothing whatsoever besides move up and down?

Full plate hides the possible cracks in the pinblock and years of Garfields' goop.

That close up photo of the Yamaha CF looks to me like this is a decorative wood covering over the actual pinblock

There usually is a dress veneer over top as pins blocks are rather ugly in appearance.

Yes Dan, that's what I was getting at. The previous posts allude to a perceived benefit of not having the plate material there which allows the pins and coils to go deeper into and closer to the block, thereby increasing tuning stability, but isn't the decorative wood essentially doing the same thing as the plate had been in this regard? as I look at this particular photo, it seems the decorative covering is about the same thickness as the plate....although I could definitely be mistaken.

Good question; dress veneers these days are usually a maximum thickness of three sixteenths while plates are usually more than a quarter inch thick and possibly more than that.

I have come across dress veneer of one layer at three thirty-seconds which is getting pretty slim.

Here is another pic of a Yammy. Interesting that the CFX uses a traditional full plate, whereas the siblings (CF4 & CF6) are as below...

Not quite Jurgen, as the pins are longer when the plate covers the pinblock .

The torque is better anyway (when the use of plate bushings was supposed to help the pinblock, I guess it is when the block is not the best quality, it allowed in fact to use cheaper and thinner blocks initially)

An open block will ovalise if not well treated by the tuner, anyway.

I have seen the sketches of differnt pinblocks illustrated in the "Forss". he state that the Yamaha pinblock have a metal plate on both sides, did you notice that (it can be for vertical blocks as grands, but I believe verticals)

I too like the feel of open face pin blocks.

The trouble has to do with the strong rotational force as seen in early cracked Bechstein plates as well as cross strain resistance.

In My recent visit to an 1865 Steinway 7'2" grand, I observed the plate and pin block rotating in such a way the action could no longer be removed ..

Additionally, to me it looks as though the Bechstein plates were cast with a "finer grain" iron which if I understand correctly is not as strong as a coarser cast iron.