B/Bb thumbkey springing ..... a question

[wally]

Apologies if this has already been well-discussed....

I'm a long-term (= terminal) entry-level player so I have lots of experience with entry-level flutes ... from low-end Andreas Eastman to high-end Muramatsu, with multiple Yamahas, Pearls, Jupiters, Kotake, Altus etc thrown in between over the years, some still with me, others long gone....

Some (notably the 200/300-series Yamahas and Pearl 505) have only their thumb B levers sprung with a flat spring whereas all the rest have the B and Bb levers sprung.

What are the advantages and drawbacks of these one/two spring arrangements? What is the reason for springing only the B? Is cost-cutting the only goal?

I have noticed more of a clunk/clink on the flutes that have only one spring (on B). In my experience, the unsprung Bb levers have a tendency to follow the pressed B down when the LH Bb keycup is being closed by other fingers (not the thumb), especially if I hold the flute at an angle that allows gravity to affect the unsprung key. Is this largely (more than likely) due to poor regulation? As best I can tell, on the flutes I have, the A, F, and Bb are properly regulated with one another and display no lost motion.

This isn't as much a problem as it is a curiosity to me. Even the low-end AE flute has both thumb keys sprung but exhibits a clunk for another reason ... worn hinge tubing.

[Zevang]

Most probably the lack of a spring in the Thumb Bb lever is because the actual Bb key already has a spring, the motion being transmitted by the conection between the Bb thumb and the Bb Key Kicker.

BTW, have you ever observed if the other brands that have a spring in the Bb Thumb lever also have a spring attached to the Bb key?

[wally]

Most probably the lack of a spring in the Thumb Bb lever is because the actual Bb key already has a spring, the motion being transmitted by the conection between the Bb thumb and the Bb Key Kicker.

BTW, have you ever observed if the other brands that have a spring in the Bb Thumb lever also have a spring attached to the Bb key?

As far as I know, all flutes have these:

- A needle spring hooked to the Bb key(-cup) on the main LH stack
- A flat spring screwed underneath the thumb-actuated B lever (lever with B keycup on its end)

But not all entry-level flutes have a flat spring underneath the thumb-actuated Bb lever. (I only have specific firsthand knowledge of the Yamahas and Pearl 505 in this respect.) Hence, on these entry-level flutes with the un-sprung Bb lever configuration, that lever may be more prone to "floating" somewhat and causing a "click" noise when the thumb-B lever is released and strikes the felt on the thumb-Bb lever from underneath.

I'd guess this key noise is mostly a matter of degree and of that, largely to be offset through proper regulation, but still .... Although the Yamaha and Pearl flutes I mentioned above seem well-regulated, in certain passages (or at least the way I play them), that thumb-Bb lever seems more prone to being a noise source. I suspect this is why it is normally found sprung with a flat spring on most intermediate and better models.

[mirwa]

Some (notably the 200/300-series Yamahas and Pearl 505) have only their thumb B levers sprung with a flat spring whereas all the rest have the B and Bb levers sprung.

What are the advantages and drawbacks of these one/two spring arrangements? What is the reason for springing only the B? Is cost-cutting the only goal?

An issue with the twin spring arrangement is sometimes the springs slip as there is no guide slot for the spring to ride in, when they slip they lock into each other and can create issues.

Twin springs IMO work better as each key can have spring tensions apllied against its applicable pivoting tube, the single spring mechanism on the B key not the lever has to lift a lever which is offset and therefore creates some resistance or sluggishness to the mechanism.

Single spring mechanisms require firmer spring tension to combat the lift of two keys, twin mechanisms can be very light individually and can individually be tweaked for the players comfort.

Long story short, bit cheaper, some advantages some dis-advantages, for most people probably un-noticeable

As a side note I am a Yamaha Warranty flute repairer

Regards

Steve

[wally]

Thanks Steve, the bit about tensioning the B key spring makes perfect sense.

I think the one on my Yamaha 225sii is sprung too tight. Another thought occurred to me, that maybe the old felt underneath the Bb lever touch might be a tad too firm, thin, or compressed.

I have a couple of flutes with the dual flat-spring setup but have never experienced those slipping or getting crossed. They either have double screws or one screw with an additional hole behind for a small protrusion from the key metal itself, which I suppose is meant to keep them aligned.

[mirwa]

Firm felt on the lever IMO is good, I actually like to replace it with regulation tech cork, this is because it allows a finer and more accurate adjustment of the Bb, simple flick of the thumb and a cleaner sound with no felt compression issues.

Yes you are correct to the double screw on a spring, I modify any that dont have them, for the exact reason of this discussion..