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Discussion Starter #1
OK, I love a good derail as much as the next, but I thought this deserved its own thread.

How about the guy (unknown since he did it before I got the horn) who carefully cut the needle point off every spring on the sax. He obviously did not know why they have the needle points and extend past the hooks.
I could imagine several scenarios either in favor or against the notion of “Why are there needle points on springs?”, but I’d rather KNOW.

Does anyone actually KNOW the answer to this (beyond “I think” or “I heard from a guy” or “I read it on the ‘net”)?

Curious,

George
 

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Grafton alto | Martin Comm III tenor
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It's for natural selection of technicians. Only masochists or the most bravest or people get to repair saxophones.

I wonder how long before we start debating the sound of pointy springs vs blunt ones?
 

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Two things:

First of all, and this is my speculation, when saxophones were first made, there weren't many readily avaiable sources of hig quality high carbon steel with good temper, in a variety of diameters and lengths. But sewing needles - before the eye is punched - those were a mass production item available inexpensively.

Secondly, the part of the spring that sticks out past the hook does absolutely nothing. You need a little protrusion past the hook so you can get them in and out, but unless he clipped them so short that they didn't reliably stay in the cradles, the guy who clipped off all the sharp points had zero effect on the function of the mechanism. This is Mechanical Engineering 101. It might have been a waste of time to clip off all those points, but it was not harmful.
 

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It's for natural selection of technicians. Only masochists or the most bravest or people get to repair saxophones.

I wonder how long before we start debating the sound of pointy springs vs blunt ones?
With the pointy springs, it's easier to focus your sound...............
 

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Fatigue life improvement?
Tapered spring will bend along the entire length.
Straight gauge wire will concentrate the bending near the post.
Bad!

The pointy tip itself may not be important.
But it looks rather elegant!
 

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The increased number of injuries to clothing and skin due to sharp points was part of the secret agreement with Big Sewing Needle Inc., i.e. resulting in even more needle sales for clothing repair and wound suturing?

(I got nothing)
 

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Grafton alto | Martin Comm III tenor
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Fatigue life improvement?
Tapered spring will bend along the entire length.
Straight gauge wire will concentrate the bending near the post.
This I think is more to the point - its not so much about a "final" sharp point which can only be there as an instrument of torture, but a gradual taper - this actually makes more sense in regard to spring behaviour. (NB: "spring behaviour" has nothing to do with what rabbits and other creatures like to get up to in spring)
 

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Discussion Starter #8
Two things:

First of all, and this is my speculation, when saxophones were first made, there weren't many readily avaiable sources of hig quality high carbon steel with good temper, in a variety of diameters and lengths. But sewing needles - before the eye is punched - those were a mass production item available inexpensively.

Secondly, the part of the spring that sticks out past the hook does absolutely nothing. You need a little protrusion past the hook so you can get them in and out, but unless he clipped them so short that they didn't reliably stay in the cradles, the guy who clipped off all the sharp points had zero effect on the function of the mechanism. This is Mechanical Engineering 101. It might have been a waste of time to clip off all those points, but it was not harmful.
Tapered spring will bend along the entire length.

The pointy tip itself may not be important.
I agree will all the above. I’m still wondering whether there is some other reason that we’re not capturing.

Fatigue life improvement?
Given that the spring works within its elastic limit (once installed), the only fatigue mechanism will be in the range of high cycle fatigue. No horn will ever see enough cycles on the mechanism to initiate HCF crack initiation in its lifetime. If it does, then the mechanism will be extremely worn, and the springs would be replaced as part of a full mechanical rebuild.
 

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No horn will ever see enough cycles on the mechanism to initiate HCF crack initiation in its lifetime. If it does, then the mechanism will be extremely worn, and the springs would be replaced as part of a full mechanical rebuild.
For what it's worth, I have had 3 needle springs break on my 89 year old alto, they may have been original, but the first 65 years of its life are a mystery to me, so I can't be sure. Was it HCF? All broke at a point just past the post, maybe 2-3mm.
I am a fan of the cheap and readily available material theory. A bunch of unfinished sewing needles with some bluing on them was cheaper than special custom springs. Are they even "spring steel" or just whatever mild steel sewing needles are made of?
 

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Discussion Starter #10
For what it's worth, I have had 3 needle springs break on my 89 year old alto, they may have been original, but the first 65 years of its life are a mystery to me, so I can't be sure. Was it HCF? All broke at a point just past the post, maybe 2-3mm.
I’d have to examine the fractography, but I’m betting that defects were initiated by corrosion rather than HCF.

I am a fan of the cheap and readily available material theory. A bunch of unfinished sewing needles with some bluing on them was cheaper than special custom springs. Are they even "spring steel" or just whatever mild steel sewing needles are made of?
The color of heat treated springs is not chemical bluing. It occurs due to high temperature in an oxidizing atmosphere.
 

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The extra length past the hook is in reserve in case the spring needs to be bent more at some point in the future. That was my 'point' in the post quoted; the idiot who cut off the tips of the springs basically prevented any future owner from increasing the spring tension. Any time you bend a spring to increase tension, you are taking up length between the fixed points at the spring base and the spring hook. If the spring is too short, it will become unhooked and you'll have to flatten it out a little to hook back up. Much simpler with the factory spring that has not been molested.
As for the needle point, I only know it was the custom in all sorts of mechanical devices to arrange the spring so it contacted the hook at about the mid point of the taper of the point. I wouldn't be surprised if it has some effect on the 'snappiness' of the action - possibly there is a slight 'whip' action at the tip because of the taper.
 

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Good question, George. I honestly don't know.
The gold Norton springs on my Buescher Big B are "blunt" at the ends and work fine. Every other saxophone I own (Selmer's and a Yamaha) have blued needle springs. One thing I can definitely testify to......needle springs (whether they're on a saxophone, clarinet or flute) impale the skin quite well. This comes from first hand experience working on them!
*thinking I should maybe go and get a tetanus shot*

J.
 

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As for the needle point, I only know it was the custom in all sorts of mechanical devices to arrange the spring so it contacted the hook at about the mid point of the taper of the point. I wouldn't be surprised if it has some effect on the 'snappiness' of the action - possibly there is a slight 'whip' action at the tip because of the taper.
I kind of doubt it but from a manufacturing perspective it is much easier to leave the spring longer to account for the tolerances in the hook position as well as some potential axial movement of the rod. Moreover, you can keep a limited inventory of springs at hand. For the actual tension, it won't matter too much but keep in mind that a spring is equivalent to a lever, that is , the actuation force it exerts decreases with distance from the base. At the same time, having a longer spring offers a lot more "granularity" or finesse for adjusting the tension further towards the midpoint.

Oh, and I forgot to mention, if you have a needle tip, it is easier to "break" the individual springs apart during manufacturing without the need to smooth out the jagged end you get with spring steel if you break it.
 

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Perhaps the points are there because it's easier to stick a pointy spring through the post hole? Speculation, of course.
 

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OI could imagine several scenarios either in favor or against the notion of “Why are there needle points on springs?”, but I’d rather KNOW.

Does anyone actually KNOW the answer to this (beyond “I think” or “I heard from a guy” or “I read it on the ‘net”)?

Curious,

George
Sharp ends in comparison to square ends have a reduced amount of friction in the spring cradle, less friction = more responsiveness, to me its simply attention to detail to maximise a parts ability to work the best it can, yes square cut ends work adequatley.

As far as springs being longer than required for potential future bending, wow.

Steve
 

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Discussion Starter #18
The extra length past the hook is in reserve in case the spring needs to be bent more at some point in the future. That was my 'point' in the post quoted; the idiot who cut off the tips of the springs basically prevented any future owner from increasing the spring tension. Any time you bend a spring to increase tension, you are taking up length between the fixed points at the spring base and the spring hook. If the spring is too short, it will become unhooked and you'll have to flatten it out a little to hook back up. Much simpler with the factory spring that has not been molested.
As for the needle point, I only know it was the custom in all sorts of mechanical devices to arrange the spring so it contacted the hook at about the mid point of the taper of the point. I wouldn't be surprised if it has some effect on the 'snappiness' of the action - possibly there is a slight 'whip' action at the tip because of the taper.
Thank you for sharing your perspective. I appreciate your contributions.

Yes, taper matters. Mechanically, the spring doesn’t know how long it is, any extra length does not contribute to the restoring force of the spring.
 

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Sharp ends in comparison to square ends have a reduced amount of friction in the spring cradle...
Not sure I can agree with that. Keeping load constant, if you reduce the contact area the unit load goes up and so the friction force will be the same -right? Unless the surfaces deform, which will tend to drive the friction losses up.
 

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Not sure I can agree with that. Keeping load constant, if you reduce the contact area the unit load goes up and so the friction force will be the same -right? Unless the surfaces deform, which will tend to drive the friction losses up.
Springs are not fixed to the cradle they rotate within the cradle, as the spring rotates within the cradle the smaller the contact area, the less drag

Steve
 
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