Strings getting stiffer

TankHenk

New User
When i string a racket with poly and i take it off the stringing machine when im finished the strings are fairly loose. But after a minute of 5 the strings get a lot firmer. What is causing this? Is it the frame that's to tight in the supports? Or is this called string relaxation?
 

First Serve

Rookie
"... when im finished the strings are fairly loose. But after a minute of 5 the strings get a lot firmer. What is causing this?..."
That is interesting. Are you in a cold environment?

Stiffness in engineering parlance refers to an elastic body (tennis string) to resist deformation/deflection/movement. The stiffness equation is Force/Tension divided by displacement.

Since after removing the racquet, one is not adding more energy to the system which is related to tension, for the stiffness to go up, the deformation has to decrease or as you called it the qualitative measure of feeling "firmer". IDK.
 

TankHenk

New User
No its not colder it happens within 5 minutes or something. I string on a lockout machine maybe that's making a difference?
 

First Serve

Rookie
After just removing the racquet from the Stringing Machine and its supports may have something do it with it. The racquet slightly deformed after removal.
 
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esm

Hall of Fame
Can I ask what machine it is and if the racquet is still 27” after coming off the machine (if it is a standard length...)?
 

First Serve

Rookie
The answer most likely is: After removing the racquet from the stringing machine mounts, which constrains the racquet head, the racquet head (hoop) ever so slightly deforms.

I have noticed this many times. Evidence of this is when I have to move the towers in slightly to get the racquet off after removing the mounting clamps at the towers.

Per the stiffness equation above (Stiffness = Force/Tension divided by displacement) with tension remaining constant and now with the string length slightly smaller from the deforming racquet head, the relative deflection is slightly smaller. Therefore the Stiffness per the equation goes up.
 
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esgee48

G.O.A.T.
Measure the length of the frame with and without strings. They should be ± 1 mm. The only time they should change significantly is when you are using different tensions on the mains vs crosses. Even here tho, I normally see ± 2 mm with up to 5# differentials.

Since you are using a lock out, you probably are getting ref tension on the mains. When pulling tension on the crosses, make sure the string is straight before pulling. I suspect that you are not getting ref tension [not even close] on your crosses due to string to string friction and not being straight. You can easily have crosses at 90% of ref tension. When you pull the racquet off the machine, the mains will squash the frame. [With CP machines, you move the crosses to break the string to string friction. The crosses end up at or much closer to ref tension.]
 
And here I thought poly was a culprit for losing tension quickly.

What string are you using? You may be onto some new technology or method. Watching this thread too
 

TankHenk

New User

The Stringing machine I upgraded the clamps base clamps and supports


Racket after stringing I try to keep the strings as straight as possible with my left hand while tensioning with my right.

The racket is strung with Solinco Tourbite 1.20 mm with 54# in the mains and 56# in the crosses. The racket is a clash 98 and i didnt measured the length before and after ( I will do next time). The ERT 300 gave a reading of 33 DT directly after stringing after 5 minutes the reading was 34 DT.

The racket came of easy of the supports only needed to loose the billiard at 6 a little t get the frame off.

I notice the same sofftness/stiffness thing in the mains as in the crosses btw.

@esm Do you want me to measure the length of the strung rocket?

Thanks for all the replies i hope i answered all of your questions
 

uk_skippy

Hall of Fame
The racket is strung with Solinco Tourbite 1.20 mm with 54# in the mains and 56# in the crosses. The racket is a clash 98 and i didnt measured the length before and after ( I will do next time). The ERT 300 gave a reading of 33 DT directly after stringing after 5 minutes the reading was 34 DT.
Given the information you've given, if you're saying the string is getting stiffer after several minutes and that you have determined this only my measuring the DT with an ERT300, then the only reason I can see is the how you've used the ERT.

The ERT, while is a great tool, you do have to be careful when measuring and re-measuring stringbed stiffness with it. Having a lot of experience with the ERT, it is easy to put the ERT in a slightly different position on the stringbed; it can be that fickle. Even testing the other side of the stringbed may give a different reading.

In short, I wouldn't worry about the readings you got as they are within 1 of each other.
 

TankHenk

New User
Given the information you've given, if you're saying the string is getting stiffer after several minutes and that you have determined this only my measuring the DT with an ERT300, then the only reason I can see is the how you've used the ERT.
Its by the feel of the string not by the measurement of the ERT just what you say if you measure several times it can vary 1 point up or down. Its just the feeling of the string with my fingers.
 

uk_skippy

Hall of Fame
Its by the feel of the string not by the measurement of the ERT just what you say if you measure several times it can vary 1 point up or down. Its just the feeling of the string with my fingers.
Then you have very sensitive fingers if you can pick that up. But strings can't get stiffer by themselves. It may follow the same physics line as getting out more energy than is put it; it's not possible. Strings can't get stiffer without a catalyst
 

TankHenk

New User
Then you have very sensitive fingers
That was what she said....

Anyway its the same thing that happens with your mains they feel stiffer after you string more and more crosses. I think its maybe what @Arak says in post #10 but im somehow the only one that notice it haha.

Im out to the girls with my sensitive fingers
 

Arak

Hall of Fame
That was what she said....

Anyway its the same thing that happens with your mains they feel stiffer after you string more and more crosses. I think its maybe what @Arak says in post #10 but im somehow the only one that notice it haha.

Im out to the girls with my sensitive fingers
I’m not a stringer but I notice what you’re describing immediately when my racket is off the stringing machine. I mostly use nylon and gut, almost never poly. The strings can be easily moved around but give it a couple of minutes and they settle and the tension feels like it should be. I don’t know why that happens and I don’t really care but it’s just an interesting observation.
 

Joe Garfield

Semi-Pro
The racket came of easy of the supports only needed to loose the billiard at 6 a little t get the frame off.
This comment stands out to me. Maybe one of the more experienced stringers can comment? Also, I thought the 6/12 supports on his machine looked kind of interesting.
 

Folsom_Stringer_Musa

Professional
This comment stands out to me. Maybe one of the more experienced stringers can comment? Also, I thought the 6/12 supports on his machine looked kind of interesting.
This is a older model of Pro's Pro. Looks similar to Gamma X-ST (mounting system similar to Gamma X-ST\602 II FC.)
The frame should not come off of the mounting system that easy as described.
On my Gamma, I always had to loosen up both 12/6 knobs.
Again how much force needed to loosen up would depend on how tightly you mount and frame\tension etc.

May be it is different for Pro's Pro machine. But I would not expect that racket would come out just loosening knobs at 6 slightly.

BTW: @TankHenk, Nice upgrade of clamp base and clamps. You bought from Baba?
 
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Joe Garfield

Semi-Pro
I always use a load spreader thats the white thing you see. Dont know if you mean that but i guess you do
Yes, that's what I was referring to. Because it has thicker plastic than the stock billiard I was just thinking it could be something that moves, flexes, or compresses as you string, which could by why the frame is snug at the beginning, but looser as you finish. So maybe just check that.
 

TankHenk

New User
May be it is different for Pro's Pro machine. But I would not expect that racket would come out just loosening knobs at 6 slightly.
Yes, that's what I was referring to. Because it has thicker plastic than the stock billiard I was just thinking it could be something that moves, flexes, or compresses as you string, which could by why the frame is snug at the beginning, but looser as you finish. So maybe just check that.
I have the original pro's pro support but they didn't work very well... See this post with the trouble so i putted on the Supports of my Tyger String eco 45 they work a lot better. But I'm searching for something better ;-)

BTW: @TankHenk, Nice upgrade of clamp base and clamps. You bought from Baba?

Im from europe so i ordered those by prospro they work very nice and are soooo much better the the old stuff i had. Only stupid thing is they are gravity release base clamps but the shafts of the clamps are to short ;-( pros pro offered me to swap de clamps (T210) for the T180 witch should work with the gravity clamps but i declined maybe ill order them for my drop weight but atm i like releasing the base clamp with the big black button.
 

Joe Garfield

Semi-Pro
Im from europe so i ordered those by prospro they work very nice and are soooo much better the the old stuff i had. Only stupid thing is they are gravity release base clamps but the shafts of the clamps are to short ;-( pros pro offered me to swap de clamps (T210) for the T180 witch should work with the gravity clamps but i declined maybe ill order them for my drop weight but atm i like releasing the base clamp with the big black button.
I have similar clamps. My gravity feature works but I use the button anyway.
 

TankHenk

New User
@struggle I know you're right just like all the others say here it's not possible to get a stiffer stringbed after x amount of time it should always get lower. It is also not possible that the frame would be so compressed in the supports that it have enough power to stretch the strings more so the tension is going up can't imagine that a rocket is so strong. It has something todo with the plastic the settlement of the string its just funny to notice.

If you string a synthetic gut then the strings move easly if you take the rocket from the stringer, you align everything nice make the crosses look nice make the mains look nice. If you put away that rocket and after 24 hours and you want to straighten some more crosses that is going less easy then 24 hours ago even the string is sometimes already broken in. The stiffness in the strings will be less but the strings are harder to move. I think that is what happens has something todo with friction or something.
 

Karma Tennis

Hall of Fame
We are simply talking about the stringbed getting tighter/firmer on its' own accord.
Sorry, I think you might be confusing "stiffness" and "tension". They are not the same thing.

Without going into a discussion about physics and molecular chemistry, suffice to say tension and stiffness are not tightly coupled. (For example, a very loose piece of steel cable is a lot stiffer than a very tightly tensioned piece of natural gut tennis string.)

Tennis string can certainly become stiffer on its own accord depending on certain conditions. This also means that a string bed can become stifer on its own accord as explained by @TankHenk in their most recent post.

But of course, the overall tension of a string bed is unlikely to increase over time of its own accord unless something exceptional is occuring (eg. short term settling of a deformed frame.)
 

struggle

Legend
Sorry, I think you might be confusing "stiffness" and "tension". They are not the same thing.

Without going into a discussion about physics and molecular chemistry, suffice to say tension and stiffness are not tightly coupled. (For example, a very loose piece of steel cable is a lot stiffer than a very tightly tensioned piece of natural gut tennis string.)
None of that is relevant here.
For any given piece of cord, it is not going to get "firmer" (the acrtul chosen wordin the OP) after it has been tensioned and secured (tied off, anchored, what have you).
At least not its' own accord (barring temperature drops, etc).
 

Irvin

Talk Tennis Guru
Not following this thread much but strings do not get stiffer in 5 minutes after you remove the frame from the machine. It just can not happen. It is possible for the shape of the frame to change after it is removed from the mounting. And because the shape of the frame changes you can get some BS readings on some devices or you may have some wired stuff going on in your OCD head but strings don’t get stiffer.
 

First Serve

Rookie
The equation for stiffness is in post #3 and is not open to subjective debate or people's opinion. IF (and big if) the given tension stays constant and the racquet head slightly contracts, which I see when taking off the racquet (albeit almost negligibly) and for a given elastic string like NG contracting ever so slightly in length, the relative deflection can decrease, thereby the Stiffness can mathematically increase without adding energy to the system, Period.

While I agree the OP may have overly sensitive OCD fingers and tendencies and it may be in his/her head, it doesnt change the fact that no laws of physics were violated.

As for the 5 minute claim, no comment.
 

First Serve

Rookie
Don't use the "Laws of Physics" as a justification for common sense on a TTW thread. You will simply be branded as some sort of lunatic!

Even though you are 100% correct. :)
Agreed, I should know better by now! And to think people think I'm nuts, because I'm a believer in "Cold Fusion" and infinite energy!
 

First Serve

Rookie
Wow, you are a nutter. I guess you are one of those really weird people who think the Earth is a sphere.
I am kidding. Too bad the Cold Fusion could not be validated and the two men who proposed it, and who thought they showed it in the lab, rushed to publish it in Nature (not the usual path for academic papers) were disproven and basically had their academic reputations ruined.
 
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