Lockout calibration question

[Irvin]

If a racket is strung on a stringing machine and a 21" section of string (measured from tip of racket to tip of gripper) is stretched 1" is there any way to get a different feel if the string was stretched by lockout, electronic constant pull, drop weight, or a big rock? No

Lockout stringing produces a softer string bed because most people that use them pull one and clamp it off. So your stretch is less because the time is less. If you pull a string longer at a given force you stretch the string more up to a point. CPs feel tighter because the pulling force continues over a longer period of time. If you use the same amount of time on a lockout you get the same result.

 

[Irvin]

I did a little experiment for those who may be interested. I used the lockout feature on my Wise so I could pull tension and read the tension after 10 seconds. I set my tensioner to 60 lbs and pulled a looped string connected to a calibrator. After 10 seconds I Wise meter read 55.2 lbs. Then I ran some tests with other strings without the scale in line reading the Wise meter after 10 seconds.

Technifibre Black Code - 54.3 lbs
Technifibre NRG2 - 56.4 lbs
Wilson Sensation - 56.4 lbs
Gosen OG Micro Amber - 56.4 lbs
Gosen OG Micro White - 56.2 lbs
Gosen OG Micro Natural - 56.0 lbs

All of reading were made with a slow pull (3 seconds) then I adjusted the speed to a faster pull of < 1 second and measure a new section of string for the Gosen OG Micro White the tension after 10 seconds was 53.1.

So I pull at 60 pounds and get a reading of 55.2 lbs. If I could adjust my stringer so it settled at 60 lbs it would really be pulling at maybe around 65 initially. But if I do that when I change strings the tension could vary by about 3 lbs (53.1 to 56.4) depending on the type of string and the pulling speed.

Forget it I am just going to use the constant pull feature.

 

[SwankPeRFection]

^^^ So glad you did that. Now can we agree that the method I've been talking about that I use to string get the exact results I've been talking about (i.e. more exact to the pulling tension than a single pull on a lockout)? I almost wish you would have done the same test but did a second pull on the Wise to see what the second initial tension and drop would have been because while I agree that it takes some of the difference away, it won't take it all away. My educated guess would be that if after 10 seconds on the initial pull is 5lbs, the second pull will probably have a 10 second wait difference of about half that.

Also, you're right, you have to develop a feel for how long to wait depending on string. This I why I don't sit there and count seconds. I simply watch the rate of drop on the tension arm.

 

[diredesire]

^^^ So glad you did that. Now can we agree that the method I've been talking about that I use to string get the exact results I've been talking about (i.e. more exact to the pulling tension than a single pull on a lockout)? I almost wish you would have done the same test but did a second pull on the Wise to see what the second initial tension and drop would have been because while I agree that it takes some of the difference away, it won't take it all away. My educated guess would be that if after 10 seconds on the initial pull is 5lbs, the second pull will probably have a 10 second wait difference of about half that.

Also, you're right, you have to develop a feel for how long to wait depending on string. This I why I don't sit there and count seconds. I simply watch the rate of drop on the tension arm.

Why do you say so? Can you explain how this validates your method/technique? You'll get better accuracy, sure. Precision is really what a stringer should be worried about, though. This also doesn't affect how a string bed stiffness (not tension) changes by the time a player actually hits with the stringbed (and the expected "feel"). If nothing else, having a tension delta (due to different string properties) of ~3 lbs is only more of an argument not to worry so much about absolute accuracy. Precision (and thus, consistency) is the first thing a stringer should be worrying about, IMHO. Lets say even if you were able to guarantee tension accuracy (even by the time a player hits with a frame), you'll still be different in SBS as compared to 99.99% of the rest of the stringers out there. Whether or not that's desirable, that's up to you to decide

 

[SwankPeRFection]

Why do you say so? Can you explain how this validates your method/technique? You'll get better accuracy, sure. Precision is really what a stringer should be worried about, though. This also doesn't affect how a string bed stiffness (not tension) changes by the time a player actually hits with the stringbed (and the expected "feel"). If nothing else, having a tension delta (due to different string properties) of ~3 lbs is only more of an argument not to worry so much about absolute accuracy. Precision (and thus, consistency) is the first thing a stringer should be worrying about, IMHO. Lets say even if you were able to guarantee tension accuracy (even by the time a player hits with a frame), you'll still be different in SBS as compared to 99.99% of the rest of the stringers out there. Whether or not that's desirable, that's up to you to decide

Negatory. If I don't follow this technique, the string bed feels looser at the same set tension. This was also one of the reason why I'd get super loose jobs from one of the previous stringers I used to use. They rushed the pulls and didn't take their time with the job.

 

[diredesire]

Negatory. If I don't follow this technique, the string bed feels looser at the same set tension. This was also one of the reason why I'd get super loose jobs from one of the previous stringers I used to use. They rushed the pulls and didn't take their time with the job.

Negatory... to what? The technique that you're pulling higher than the reference tension requested? That you're calibrating artificially high? (Unless I'm mistaken, you haven't actually explicitly stated what your method/technique is. I assume since you chimed in in agreement to mik that you're doing the same thing. If you're calibrating high, it's sort of a duh statement to say that the string bed feels looser as compared to someone who is calibrating to reference. Like I said before, from the discussion of reference tension, the operator needs to be abstracted away, and we need to assume competent operators (this isn't always the case, and I'm happy to admit that). You're talking about two separate things, here.

 

[yan.v]

Very many people see it that way but it is not correct. If the string kept getting longer I would have loops of string on the outside of my frame. It does not get long it changes. A string when you pull it resists change and will only stretch out when enough force is applied. Depending on how much force is applied and the amount of resistance to change I will have tension in the string. The more the stretch, the more the resistance, and the more the tension. When you clamp the string the stretch does not change (in a perfect world) but the resistance to the stretch goes down as the string relaxes its resistance and therefore the tension drops.

Now let's look at a calibrator. When I got my gamma machine a calibrator came with it with two looks of string on each end. Now the spring inside the calibrator is never going to change or it would not be worth having. Just think you use it one and it reads 60 next time 58 next time 56. Not good so the only thing that is relaxing is the strings on each end of the calibrator. So you have two lengths of doubled over string with a 6" section if the middle with something that does not stretch (in only measure the force applied.) So you let the string settle for a given amount of time and that is where you calibrate your stringer when set to 60 pounds.

Now you tension a string in a racket with a single string. Because the string is not doubled over it will stretch more after lockout. And that single string is longer. Because the string is longer it will stretch more after lockout. So when you set your machine to 60 lbs if pull more than 60 pounds and your don't know how much more. And because your string is losing more tension for the reasons stated above you have no idea of what your tension is.

EDIT: And unless the string your are stringing is the same as the string tied to the end of you're adding more variables into the equation. It only makes sense to me to control the pulling force and the only way you can identify that is to adjust the lockout for the force on the lockout's dial when it locks.

Now you're just playing on words. By elongating, I did mean stretching, which doesn't really change my arguments. Although I agree that the term elongating wasn't really used properly.

If someone wants to have a closer tension to a constant pull machine without bothering to pull twice, the first thing they'll do is pull with a couple more lbs. If instead of doing that, they just calibrate the machine so the string settles to the desired tension, I don't see what's wrong with that.

As long as you're consistent from one string job to another, it won't cause any problem, because anyways, tension will almost always differ from stringers to stringers for the same reference tension .

 

[struggle]

no need to add another variable IMO. we all are gonna get different results on the exact same machine set at the same tension, same frame/string etc.....without throwing in another variable.

having said that, do whatever you like.

 

[diredesire]

Now you're just playing on words. By elongating, I did mean stretching, which doesn't really change my arguments. Although I agree that the term elongating wasn't really used properly.

If someone wants to have a closer tension to a constant pull machine without bothering to pull twice, the first thing they'll do is pull with a couple more lbs. If instead of doing that, they just calibrate the machine so the string settles to the desired tension, I don't see what's wrong with that.

As long as you're consistent from one string job to another, it won't cause any problem, because anyways, tension will almost always differ from stringers to stringers for the same reference tension .

Because there is variance based on strings, you can't add a linear/discrete/static offset that will work the same way for all string types. We as stringers don't (generally [attempt to]) control what happens once the frame is off the machine, but adding a static offset is actually introducing an additional variable, which actually makes you less consistent (as compared to others). You settle closer to desired tension, but what I'm saying is the absolute "tension" figure isn't even the target in the first place. If you keep moving your stringbed stiffness (which is what the final product is, that people actually hit with) around, it only serves to make your product less accessible to a customer IMHO.

 

[Irvin]

... My educated guess would be that if after 10 seconds on the initial pull is 5lbs, the second pull will probably have a 10 second wait difference of about half that...

Pulling at 60 lbs on lockout first pull after 10 second again was 56.4 lbs. Second pull after after 10 seconds wait again was down to 56.6 lbs. Rather than 50% less it is about 0.3% less.

 

[Irvin]

...If instead of doing that, they just calibrate the machine so the string settles to the desired tension, I don't see what's wrong with that...

Assuming I am going to string a racket with SG what tension do I pull to settle in at 60 lbs. Now the next racket I string with a poly is there any difference. Now I want to string poly at 30 lbs what then?

 

[yan.v]

Assuming I am going to string a racket with SG what tension do I pull to settle in at 60 lbs. Now the next racket I string with a poly is there any difference. Now I want to string poly at 30 lbs what then?

I understand that, that's why I've been saying that it doesn't work when using different strings since the start.

 

[tennis4]

In reality, do you spend 10 sec to achieve the consistency or it can be done in shorter time, 5 sec? If you pull again, ... does that mean the manual crank could take longer to reach the required tension than dropweight?

Forgive my ignorance. I am trying to figure out what's required to deliver the similar result in manual crank as opposed to dropweight.

I did a little experiment for those who may be interested. I used the lockout feature on my Wise so I could pull tension and read the tension after 10 seconds. I set my tensioner to 60 lbs and pulled a looped string connected to a calibrator. After 10 seconds I Wise meter read 55.2 lbs. Then I ran some tests with other strings without the scale in line reading the Wise meter after 10 seconds.

Technifibre Black Code - 54.3 lbs
Technifibre NRG2 - 56.4 lbs
Wilson Sensation - 56.4 lbs
Gosen OG Micro Amber - 56.4 lbs
Gosen OG Micro White - 56.2 lbs
Gosen OG Micro Natural - 56.0 lbs

All of reading were made with a slow pull (3 seconds) then I adjusted the speed to a faster pull of < 1 second and measure a new section of string for the Gosen OG Micro White the tension after 10 seconds was 53.1.

So I pull at 60 pounds and get a reading of 55.2 lbs. If I could adjust my stringer so it settled at 60 lbs it would really be pulling at maybe around 65 initially. But if I do that when I change strings the tension could vary by about 3 lbs (53.1 to 56.4) depending on the type of string and the pulling speed.

Forget it I am just going to use the constant pull feature.

 

[Irvin]

...I am trying to figure out what's required to deliver the similar result in manual crank as opposed to dropweight.

When I pulled fast with a lockout at 50 the tension fell from 60 to 53.2 and when I did a longer pull the tension fell from 60 to 56.4. Therefore longer pulls produce a higher tension in the final string bed.

When using a CP stringer you pull the string and that PULLING force continues to pull until you clamp the string which isolates the pulling force from the string in the racket. That operation takes about time and the longer that pulling force continues to pull the tighter your string bed will be.

If you pull a string on a lockout immediately after lockout the string starts to loose tension. If you pull again 10 seconds later it is as if you held a continuous pulling force on the string for 10 seconds almost and the tension goes back up to the reference tension.

So if you want to get the same result from a lockout as you do a CP I can only assume you want a tighter string bed. Three are two ways to do that:

• Raise the tension

• Pull slower

• Make successive pulls

I think this is the easiest way:
http://www.youtube.com/watch?v=3aYI5DXQxSA&feature=plcp

The reason I like doing more than one pull is because each one you do can be repeated over and over.

 

[tennis4]

When I pulled fast with a lockout at 50 the tension fell from 60 to 53.2 and when I did a longer pull the tension fell from 60 to 56.4. Therefore longer pulls produce a higher tension in the final string bed.

You meant 10 sec?

It seems the slower the better.? Does it apply to the second pull? Should the second pull be in the same pace as the first pull?

Another question: let's say I am going to string two racquets, one for 60 lbs and the 2nd one for 45. Should I do the calibration individually?

Thanks.

 

[Irvin]

No I think I meant 60 but you get the idea.

All pulls should be the same so build up and pace that is repeatable.

Lockout stringers should be linear at all tensions but that is not necessarily the case. What I meant is if you set the dial on the stringer to 60 it should pull 60, and if you switch to 45 it should pull 45. But that does not always happen.

Find out what your stringer does and you may even want to draw a graph for yourself so when you string for someone else you know what you're pull when set at any tension. It should make sense when you have the actual tension on one axis and set tension on the other.

 

[SwankPeRFection]

No I think I meant 60 but you get the idea.

All pulls should be the same so build up and pace that is repeatable.

Lockout stringers should be linear at all tensions but that is not necessarily the case. What I meant is if you set the dial on the stringer to 60 it should pull 60, and if you switch to 45 it should pull 45. But that does not always happen.

Find out what your stringer does and you may even want to draw a graph for yourself so when you string for someone else you know what you're pull when set at any tension. It should make sense when you have the actual tension on one axis and set tension on the other.

Why doesn't it always happen? If it's not dependable to be a linear mechanism, then it's pointless to expect it to be properly calibrated to fill everyone's request. Suppose you calibrate for 55 exactly because most of your clients string around that tension, but 60+ and 50- tensions are loose by 3-5 pounds due to whatever crazy crap the machine is doing. When I ask you to string at 48, I guess I should just accept that I'll get 42? (Calibration is on the loose site for 4x tensions and you're not double-pulling because you could be busy that day.) What should one do in that case?


BTW, I'm not trying to argue with you, but I'm just trying to figure out how you handle such issues when they come up with cranks because this is what drove me to draw the line and string for myself.

 

[tennis4]

I think this conversation help me to refresh some college courses ... The tension and compression probably is not as linear as we like. If the spring is aged, the result could be more unpredictable.

Why doesn't it always happen? If it's not dependable to be a linear mechanism, then it's pointless to expect it to be properly calibrated to fill everyone's request. Suppose you calibrate for 55 exactly because most of your clients string around that tension, but 60+ and 50- tensions are loose by 3-5 pounds due to whatever crazy crap the machine is doing. When I ask you to string at 48, I guess I should just accept that I'll get 42? (Calibration is on the loose site for 4x tensions and you're not double-pulling because you could be busy that day.) What should one do in that case?


BTW, I'm not trying to argue with you, but I'm just trying to figure out how you handle such issues when they come up with cranks because this is what drove me to draw the line and string for myself.

 

[fortun8son]

I've had similar problems with an old Neos, especially when jumping from racquetball (30s) to tennis (50+) and back.
I would recheck with the calibrator for each jump to be sure.
One must also take care not to bend the lockout lever inwards when releasing the lock as this can affect the lockout tension as well.

 

[Irvin]

Why doesn't it always happen? If it's not dependable to be a linear mechanism, then it's pointless to expect it to be properly calibrated to fill everyone's request. Suppose you calibrate for 55 exactly because most of your clients string around that tension, but 60+ and 50- tensions are loose by 3-5 pounds due to whatever crazy crap the machine is doing. When I ask you to string at 48, I guess I should just accept that I'll get 42? (Calibration is on the loose site for 4x tensions and you're not double-pulling because you could be busy that day.) What should one do in that case?


BTW, I'm not trying to argue with you, but I'm just trying to figure out how you handle such issues when they come up with cranks because this is what drove me to draw the line and string for myself.

Very simple answer is that it is not properly calibrated. There is a short calibration that will always work but if you tension is not linear there is a more complicated way of calibrating it. If calibrated correctly they are linear. 40 = 40, 50 = 50, and 60 = 60. I have never had to do more than the simple calibration so I am not sure what all is involved in the other method.

I am just advising it could happen.

 

[Irvin]

I think this conversation help me to refresh some college courses ... The tension and compression probably is not as linear as we like. If the spring is aged, the result could be more unpredictable.

The springs are designed to never age. If it is the spring that has lost some of its spring then you only need the simple calibration. If you ever get a notion to take the whole gripper assembly off your tensioner you better make sure you get it back on exactly correct.

 

[Irvin]

I've had similar problems with an old Neos, especially when jumping from racquetball (30s) to tennis (50+) and back.
I would recheck with the calibrator for each jump to be sure.
One must also take care not to bend the lockout lever inwards when releasing the lock as this can affect the lockout tension as well.

I am not sure about the Prince instructions but Gamma does not advertise the long version. If you have any problems though they are more than willing to distribute. This could happen to any lockout machine the more people start messing around with everything the more out of whack they are going to be for those like me who go by "when all else fails read the directions."

 

[BigGriff]

LOL, you guys are a lot like "expert" Tennis pro's I see teaching to beginners. You guys way overload a new stringer constantly with tooooo much information.

I forgot what the OP mentioned after 2 pages of reading. I would have given up and called the machine manufacturer.