# Constant pull vs Lockout

Discussion in 'Stringing Techniques / Stringing Machines' started by Irvin, Aug 2, 2011.

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## Who here thinks this 5 year old thread has outlived its usefulness and should be locked or deleted.

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1. ### IrvinG.O.A.T.

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Many people have heard so many times constant pull is so much better than a lockout they believe it. They have no idea of why it is just becasue of their mindset. It cost a lot more money to make a constant pull electronic tensioner that it would stand to reason the manufacturers would want you to believe the more expensive stringer is the best.

Let's first think about how the lock out tensioner works. When you tension a string at x pounds it will stretch y amount then the tensioner locks out. No matter how long you leave the tensioner engaged the string is stretched y amount. Tension a string for 1 year and come back and it will still be stretced y amount. The higher your reference tension is the longer the string stretches and vice versa.

Now let's think about the constant pull. When you tension a string it stretches to a certain point and the CP tensioner stops pulling. Then the string stretches a little more and the the CP tensioner pulls more. That continues to happen over and over and over again. If you tension a string for 1 year anc come back it will have reached the point of no return and may have actually broken the string.

So my question if would you rather have all your strings stretched the same amount or different amounts? Keep in mind that different amounts of stretch is just like different tensions. If you use a constant pull machine the only way you get the same amount of stretch is to have a perfect rythem and stretch every string for the same amount of time.

Discuss.

Irvin

2. ### RonaldoG.O.A.T.

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The string pulled on a lockout stringer will lose tension immediately, a pound or more within 20 seconds. Discovered this using a calibrator.

3. ### mikelerModerator

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Interesting take on it Irvin with the 1 year analogy, looking forward to following the comments.

4. ### IrvinG.O.A.T.

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Actually it is much greater than a pound. If I set my constant pull to 60 pounds in the lockout mode it will be down close to 50 is about 1 minute. The majority of the tension loss is just after lockout. We all know that tennis string is somewhat elastic but there is also a tendancy for the string not to stretch. Different strings stretch at different rates that is a given.

Again my question is would you prefer the same stretched the same amount or not?

Irvin

5. ### IrvinG.O.A.T.

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Some CP tensioners (like the Wise) have the ability to pull in either the lockout mode or the constant pull mode.

Would it be better to pull tension at ~110% on a lockout or for ~5 seconds on a CP? As an informed customer I would like to have the choice and not leave the choice up to someone else.

EDIT: Some people switch from a lockout to constant pull and vice versa. For a give string how much tension is lock after about 5 seconds on a lockout? If you knew the answer to that and you had a tension that had both modes you could determine that rather easy. You put the machine in the lockout mode and tension a string for ~5 seconds. The result after 5 seconds is the tension you should use on a lockout. If you are used to having your racket strung on a CP and you move to a lockout you could use the reverse.

Irvin

Last edited: Aug 2, 2011
6. ### ATP100Professional

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As I am sure you already know, consistency in the person stringing is more important than the stringing machine.

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7. ### IrvinG.O.A.T.

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No I do not know that. I feel that I am extremely consistant when I am stringing a racket. But if I had one clamp that always slipped, or the center point on my turntable was consistenly different, or I was always pulling different tension I would be concerned. Consistenly bad is consistenly bad whether it is the machine or the person does not matter.

Don't fool yourslef by thinking you can do a good job by doing a bad job 100% of the time.

EDIT: If that were true I could make a fortune in MLB. I believe it would be possible for me to have a 000 batting average every year and never field a ball. Can't do much about walks though but I could make sure I never made it home. LOL

ANOTHER EDIT: Don't get me wrong. I think ALL machines are capable of doing an excellent job and most of the blame for a good job goes to the person. What I am trying to discuss is whether you think a CP or a lockout is more consistent.

Irvin

Last edited: Aug 2, 2011
8. ### RonaldoG.O.A.T.

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Does the stringer pre-stretch? Clamp immediately and consistently on a lock-out? Allow 5-10 seconds for the CP to stretch the string?

9. ### IrvinG.O.A.T.

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Stringer? Is that the person or the machine? Does not matter because the stretch is ALWAYS the same as oppossed to a CP. What is the difference in stretch between 5 and 10 seconds? Not sure where you are going here.

Irvin

10. ### ATP100Professional

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Sorry, I was assuming a basically competent stringer.

11. ### RonaldoG.O.A.T.

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Person pre-stretch to remove or lessen coil memory.

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I'm going to argue here that the stretch isn't the same. Lets say you were tensioning a string, and you cranked fast and hard on the tensioner @ 1/10s. The next string you do a (very) slow pull at 3s. Measure the stiffness of each over time, and you'll find they're not the same. While there's a reference spring in the tension head, it can be tricked, and the material under tension also responds differently depending on tensioning speed.

I believe, to a certain extent, a CP machine actually compensates for material variance (removes the stringer from the equation). While you're correct in your example that the CP will continue to pull slack and after a year's time the tension/stretch pulled will vary versus a string that was only tensioned for a second.

However, most CP machines have a degree of sensitivity (as far as when to re-pull to reference). The vast majority of <\$1000 electric machines have a pretty crappy sensitivity indeed. When we're talking about electronic/microcontroller based, the precision is much better indeed. Regardless, just from experience, you put a string under tension, and you watch (dropweight) or listen (electric) as to when the string stops stretching (within reason). After the tensioner stops chattering, you clamp. This is repeatable, and only dependent on things that theoretically are very consistent (string composition/chemistry/elasticity/etcetc, as well as machine electronics/mechanics).

Even IF you went by a timing (aka tension then re-clamping at the soonest you can) on a constant pull, the variance is < 1s [considering an experienced stringer can complete the unclamp-clamp procedure itself within ~1-2s]. I don't think this is a very big change. Note this is considering that you're not even waiting for the tensioner to stop doing it's thing.

While I'm not going to state that one system is better than another (naive), I think CP/electric machines forgive an inexperienced/inconsistent operator better than cranks.

13. ### IrvinG.O.A.T.

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Absolutely no argument there at all. The slower you crank the more you pre-stretch the string. If you were to stretch a string in 1/10 second it would more than likely approach it breaking point. You may have stringer stretch real slow though but more than likely he would do it every time.

I agree with you thought I don't know which one is better but it is nice to discuss.

Irvin

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Agree, you actually learn a lot of un-said stuff when listening to other people. TBH, I'm glad the techiques/machines section is taking off!

As far as which is better, there are definitely things I like about both, but they're different systems, and I don't think it's easy/simple to try to compensate for both. I'm one of those guys that recommends: understand the differences and move on. I personally really like the feel of a synthetic gut string bed strung on a crank , but I don't go out of my way to replicate it

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15. ### IrvinG.O.A.T.

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^^Well said I totally agree.

Irvin

16. ### SW StringerSemi-Pro

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Tests I've done with my crank machine indicates the triggering mechanism is accurate within plus or minus 3/8 's of a pound which was much better than I had expected. So if one were to pull at the same continuous speed pull after pull then all your pulls would be tensioned within that same tolerance. With a crank you get one pull, one stretch - for a uniform string diameter. Now with a CP machine you get multiple pulls, multiple stretches and after clamping - how many pulls did you get, will you get a uniform string diameter? If you're able to clamp off with the same number of repulls per string you'd expect to get a pretty uniform stringbed. But can you guarantee the same number of repulls? Don't think so.

But wait, there is one electronic tensioning system that guarantees the number of repulls, it's the Wise tensioning head. Set it to lock-out mode and you get one pull - with electronic accuracy (load cell) that should far surpass 3/8's of a pound.

Now let me back track and share my thoughts on what you have to control to ensure a uniform stringbed. You must control each strings tension AND just as important you must control each strings diameter. Those two factors string tension AND string diameter dictate (mathematically) that strings stiffness and ultimately the string bed stiffness. You control the tension by setting the dial, knob, weight,etc. You control the diameter by setting the number of pulls and pull speed.

And that's the problem with many of the electronic CP machines out there today - you don't really have control over the number of pulls nor the pull speed. They make it so automatic that the user really has no control over those parameters that ultimately control the string diameter.

Hint to CP designers: do like Herb Wise, let the user control the number of pulls AND pull speed - POWER TO THE STRINGER!!

In summary, the best machine available today is the Wise set to lock out mode, the next best is a properly used crank machine, next come all those high end CP's in that order. (With a simple software change all the high end CP's could be on top if they would allow stringer selectable speed and number of repulls).

That's my 2 cents.

17. ### RabbitG.O.A.T.

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First I'd like to throw some kudos at Irvin, this is a great thread. Second, I'd like to offer up that it is my observation that the vast majority of the posters on these boards overthink too much as it relates to gear; grams, pounds, kilos, balance points, string weight (for Pete's sake), most aerodynamic dampener, and the hits just keep on keeping on.

That said, here is what I think. I, like Irvin, am a one-year veteran of Wise ownership. If I am honest, the biggest plus I see from the Wise is this:
• Ease of stringing. The Wise allows me to string more with less fatigue and less menial tasks.
• Accuracy of stringing. This is probably not what you thought. When I say accuracy, with the Wise, due to its digital tension readout, I know immediately if a clamp is not doing its job and needs cleaning or adjusting. With my lockout tensioner, this was not always the case. Once that is a certainty, yes, the Wise does offer more consistent results than the lockout.
• Speed of stringing. I find that I can string faster with the Wise than a lockout.
• Consistency. My crosses are straighter, the tension is more even, and it's an all around better string job.
Now, some realities as well:
• Conversion to lockout. Most of the folks I string for have been used to their racquets being strung on a lockout (Neos) machine. To compensate for the difference in feel, I set the Wise to lockout mode and their usual tension. Then, I pull tension on the first main. I get what the string settles at after an average amount of time from tension to clamp. I then set the tensioner to that tension and reset the pull to CP.
• It's expensive, and probably not justified for a home stringer. But hey, you gotta spend it some time.
• Using a Wise is fun. After ten+ years turning a crank, the Wise is just plain cool. (If I ever do buy another machine, it'll be an electronic.)
Bottom line is that if I strung two racquets using the method to convert a lockout tension to CP described above, and I played with them afterward, I probably wouldn't be able to tell the difference. And that is exactly how it should be. Tension is a number, a relative number and should be thought of as just that. It is no silver bullet for your game.

Great discussion.

18. ### IrvinG.O.A.T.

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^^I agree with that. When peple bring me a racket and don't know or care how it should be strung I suggest midrange. Then if they want it softer I go down in tension if they want it tigher I go up in tension. You are right mid range is just a number. After it is strung that number is gone anyway. Many people think if they have their racket strung at 60 lbs it should have 60 pounds of tension on each string. Nothing could be farther from the truth.

Irvin

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Unfortunately, for me, this is the major ISSUE. People THINK they know what they want, and they don't want to be told otherwise. I'm curious to hear how Rabbit deals with this, if at all. IMHO, the reason I get caught up in the minute details is because people are so ill-informed and stubborn.

I consider tennis to be a very internal/mental game as well as a physical sport. If a customer wants "60 lbs" and then complains that the frame is strung too tight... what are you really supposed to do there? Explain the differences between a crank and a CP? Suggest a lower tension? "I want it at 60 lbs, I've strung it at 60 lbs for a long time. The racquet you gave me is too tight!"

Thoughts from the "WISE guys"?

Edit: WISE guys would be a cool club name..

20. ### RonaldoG.O.A.T.

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Warn those customers that 60# on your machine may feel more taut than the usual.

21. ### IrvinG.O.A.T.

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That very issue came up today with me. I strung a racket with the same string that was in the racket (PSGD) and at mid range (60 lbs) because that is what was asked for. Today they called back saying it was too tight and didn't know much about stringing. Then I found out it had been about 10 years since the racket was strung. I explained the process and what happens to strings over time and that she may want to try a softer string and/or lower tensions. I offered to string the racket again for \$5 (cost of string) but each is going to have to determine on their own how they want to handle it. I would rather have a happy customer that promotes my stringing service for me than an unhappy one that runs me down.

Irvin

22. ### RabbitG.O.A.T.

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Well, I am lucky in that respect. Folks that I work with usually aren't that hard headed. If they are insistent, then I ask them who had been stringing for them and pretty much know what machine that is. Then, I use the afore described method to translate that tension to the CP tension. I have been very circumspect about following up with people on their frames. So far, no complaints other than one guy whose frame broke a week after stringing....the frame was about 20 years old and he had played with it several times after I strung it.

DD, I think you string for a college team don't you? My clientele is a little less demanding than that.

That is exactly why I came up with translating tension. They tell me what they have been getting it strung at using a lockout, I take the string I'm going to string for them, pull tension on it in lockout mode, wait about a good 3-count and see what the tension is at that moment. Then I set that tension in CP mode.

R. D. Cross in one of his books said that in a blind test, really good tennis players couldn't tell the difference in 10 pounds of tension when all they could do was hit a ball (no bouncing off their palm, etc). I figure 3.5's to 5.0's aren't going to be able to feel 1 - 2 pounds difference with what I do. But, I do pay attention to tension as it is one of the Holy 3 of stringing.

Now that is cool......

23. ### RabbitG.O.A.T.

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OH, and let me add that I agree constant pull is way over emphasized. I think the more important aspect of any stringing machine is the mounting system and clamps.

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Yeah, I used to string for a college team, I recently graduated and moved away, though. I don't think it's necessarily just a demanding clientele, I'm also relatively young. I think the general perception of lots of pro shops around here is that there's primarily high school "kids" stringing frames, and most of them don't respect the "craft." I think there's a built in amount of disrespect due to age I don't take it personally; most of the stringers that are around my age range that I've met/talked to don't really know their stuff that well.

The problem isn't a lack of warning/information. I've tried different approaches in terms of communicating systematic issues with my customers, but I've learned over the years that there's no reason to over-complicate things with clients unless they are looking for more knowledge/understanding. Some people also think I'm trying to "sell" them on something. I'm not really the type to hype myself up, and for good reason: most people offering services spew a fair amount of BS, IMHO.

As far as informing someone it'll feel more taut, without a proper qualification, I don't want to make that sort of claim. I don't want to simplify a complex issue, and i don't want to add complexity to a simple issue. I feel that people that don't have a good understanding of stringing tend to think it's some sort of magic or something, and they tend to be afraid to ask questions. I'll often ask what kind of machine it was strung on before, and leave it at that.

Yep, this is my fire-fighting technique. I'll throw in a free labor and restring @ cost of string. Happy customers are always good

Last edited: Aug 3, 2011
25. ### GlenKProfessional

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I have a Gamma X-ELS CP and love it. I have become very consistent in my string jobs and generally pull 2 to 3 pounds above the set tension. However, with most strings it comes down to very close to what the customer wanted.
I strung my own racquet yesterday at 55/53. It came off the stringer as 56.8lbs, per racquetTune. By the time I hit the court today, it was reading 54.5.

When I pick up a new customer I explain the situation. If they want 60, I tell them it will be a real 60lbs or very close to it. On the first job I always offer a restring if they are not satisfied. From that point on, we are on the same page and I've had no issues.

Most of my customers had their racquets strung from the same place I did before I started stringing. He used a Alpha crank and was always 4 to 5 pounds under requested tension. Primarily because of the lockout machine and quite frankly, he's just not a very good stringer. Doesn't straighten strings and shoots the breeze with who ever's around so his time between pull and clamping varies greatly.

But once they have gotten used to actually having their racquet strung at the correct tension I've had no problems. It's just a touchy situation with some of these guys because they think he's a great stringer.
I have kept most of this to myself, except for explaining the difference between lockout and CP..

Excellent thread and discussion. I was wondering how others were handling this.

26. ### TennisCJCLegend

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Logically, it seems that a lock-out could produce more consistent results because the machine pulls to tension and then stops while a Cpull continues to pull. Depending on the time variance under Cpull tension, the string could be stretched more or less. If you tension and clamp off at a consistent number of seconds with Cpull, the results will also be very consistent.

Having said that, I like the results I get with Cpull. I don't really stress out on clamping off in the exact number of seconds and the finished product is very good. I think Cpull string jobs feel tighter off the machine and keep tension better maybe due to more string stretch while under tension. I would not trade my Cpull for lock-out.

27. ### rufusbgoodSemi-Pro

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If I owned a Wise tension head and 4 identical racquets and the weather outside was really lousy, here's an experiment I would run:

1. I would string one racquet constant pull.
2. I'd string one with 10% pre-stretch.
3. I'd string one with the machine set to lockout.
4. And I'd string one racquet with the old spring loaded tensioner.

After I figured out what tension to string each one at so that they all started out at the same DT reading (easier said than done of course), I'd head out to the court and playtest them to see if I could discern any difference in playability. And then I'd report back here with my findings.

Then I'd do the same experiment with poly strings.:twisted:

I just visited the Wise website and I noticed that the tension heads they are shipping these days don't include a "lockout" setting. I guess people weren't finding much use for it. I use it infrequently myself. Mostly when folks ask me to string something I know will be too tight and I want it to come out looser without deviating from their instructions. I'd say it's equivalent to roughly a two pound drop in tension.

Even though I own a machine that has this capability, I have never used it on one of my own racquets. I have been meaning to but have never gotten around to it. I think the disadvantage of this setting is that it robs you of time to manipulate the string into a straight line. A better design would be a variable timer so that you could adjust the number of seconds you have before the machine locks.

In another thread recently I suggested to someone that using the pre-stretch feature on a constant pull machine ought to result in a good simulation of a lockout machine because in each case the tension hits a peak and then quickly drops lower. Likewise, I would expect the constant pull setting to do a good imitation of a drop weight machine. And I think the "lockout" setting on the Wise unintentionally is a whole new animal, essentially it's constant pull with a very short timer. I could see how it might deliver the best stringing the machine is capable of and it deserves some testing.

28. ### rjwProfessional

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Good discussion...

I just bought a used lockout machine and was having fits trying to calibrate it. I soon realized that outside of using something rigid, it was never going to hold the selected tension. This was confirmed by knowledgeable persons, and in that I was trying to calibrate using the exact same string that I used for my first 2 stringing attempts, I knew exactly how slow to pull, and how long I had to clamp, and how much tension loss there would be, if I locked the clamp down within a certain time.

Before I got into this, and although I could be wrong, I think that myself and most rec players have no clue as to what machine or type of machine their previous stringer used???

and at \$12 to \$16 labor that is charged down here in South Florida, I don't know how any private stringer could make much money, unless they had a great reputation and/or knowledgeable customers or possibly customers that couldn't feel the difference?

If someone brought you their racquet and asked for natural gut at 60 and then came back and said that it wasn't right, then who eats that?

things could get a little sticky, I would imagine.....until you build up a reputation for quality work, I guess.

I know that my racquet strung on a 9k BAB electronic cp machine comes out tighter than on mine, but I actually think that when strung on mine it plays better..power AND control wise...which seems a bit strange???

thoughts anyone?

Last edited: Aug 3, 2011
29. ### RabbitG.O.A.T.

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I think that's where knowing the difference in machines comes in and/or having an option like the Wise for different pull methods.

If someone has a problem with a string job I've done, I'll redo for free if they'll purchase the string.

I would say then that you were getting your racquets strung too tightly on the CP. Anyone who says their frames feel good just before the strings break is misinterpreting the feel of the stringbed as "broken in". Truthfully, it was too tight to begin with.

I do notice, especially more with a poly/multi set up like I use, a degredation in my game, especially the serve when a string job is spent. If I have to struggle holding serve (all things being equal), I'll bag that racquet and get my other one. When I get home, it's to the rack with the old string job.

30. ### MayDaySemi-Pro

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Since the point of when to clamp is essential for consistency, would the next logical item to "automate" be the clamps? Wouldn't that make Cpull electric machine much more appealing than lockout?

Set the string, set the clamp, press the button, machine Cpull to desired tension, clamp automatically close and lock within certain set of Cpulls or milliseconds, tension head automatically releases within configured milliseconds after clamp lock.

Last edited: Aug 7, 2011
31. ### rjwProfessional

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I'm noy going full force into the stringing business at moment, but I can see how things could go downhill for those that do.

I bought my latest racquets before I discovered the joy of DIY stringing. Based on how they felt at 58 and 60, when it came time to do it myself, I chose 56/52 based on how 58 from the cp machine felt. The actual pitch of the strings was fairly close to the cp 58, so I thought that I was NOT way off.

I really don; think that I'm losing as much as 5 lbs. from my LO machine as many others seem to think...but maybe I am...I will invest in that gamma ert gizmo and log everything...

32. ### kato669Rookie

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rjw,

IMHO, Unless you have the money (if yes, then by all means, go for it then), for the home stringer, investing in an ERT seems to be a bit of overkill.

If you have a PC or laptop with a microphone, download freqmess (http://marc.roettig.org/tennis/freqmess.php). This uses a similar concept as the ERT (string vibration frequency) to measure string tension. If you have an iPhone or Android phone, Freqmess makes an android app (about \$1.50 USD) and the iPhone has Racquettune (not based on Freqmess but a similar algorithm and method, about \$1 USD). The PC app for Freqmess is freeware. Lots of people use these with good reviews. I use it myself on the PC and on an Android phone...it's great! Give it a try if you want to consider an alternative.

33. ### rjwProfessional

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I would prefer NOT to invest a lot of cash at the moment. I would however prefer to be using a more scientific approach to stringing.

The old tap it with the palm of my hand approach might be better if I actually recorded the pitch, but I don't.

I like the PC version, went and downloaded the program, but the link on that page, to a TW thread gives me an error message.

Thanks so much for the headsup

34. ### kato669Rookie

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Also, instead of the palm of your hand, try a dinner spoon or the handle of a butter knife . These make pretty good twangs and are easily repeatable for taking an average reading.

Last edited: Aug 8, 2011
35. ### rjwProfessional

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Can I add strings to the data file? I would imagine if I accurately weigh a length of string and measure its diameter, I can get the correct density?

Why have some of the links on this gone dead? Is it because it's free or something to do with TW not allowing this?

thx

36. ### kato669Rookie

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Yes, you could just edit the text file and add your string. Or you can just change the value on screen to the values you want to use.

TW doesn't have anything to do with Freqmess (other than a forum to discuss it). Maybe Marc stopped supporting the Windows 98 version (which is what the second link is for) which kinda make sense since the end of life on that product was quite awhile ago. The xp version (which runs fine on Vista and I imagine Windows 7) works fine.

37. ### Power PlayerTalk Tennis Guru

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I have never used a crank. I do know that my constant pull auto drop weight has gotten me incredibly accurate results and a stringbed that I personally feel confident with each time I hit the courts.

I am a much better stringer now then last year though as well. The cool thing is that I don't even consider buying another stringer anymore..I am simply working on consistency and speed and I know the timing and feel of the CP a lot better now.

I am sure it would be the same if I used the crank.

38. ### rjwProfessional

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I like the feel of my crank machine. I can see that the machine in general is really old techology, but it seems to work well enough. If I were to go into business, then it might be a bit more of a task to keep people happy if they bring a stick done on a cp machine, but it would be interesting to see if (as some claim) many people can't feel +/= 5 lbs or so difference.

I would consider a Wise head (down the road) or a diy project, but I really DO NOT want to lose the supposed feel difference from a LO machine vs CP

Hope this makes sense to someone??

39. ### ATP100Professional

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Stringing a racquet is easy, just takes practice, but, you can make it complicated, like a lot of people on this board do.

The choice is yours.

40. ### Posture GuyProfessional

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very interesting thread. I'm in the midst of searching for a machine. Used to string with a Prince Neos 1000 8+ years ago. Sold it when we were moving (for a variety of reasons), now want to get back to stringing. Just for myself and maybe a few others.

One question I have on this topic, most people seem to be creating one monolithic category called "constant pull" and everything is either constant pull or crank. And maybe that's true. I've been looking at the Stringway approach and I'm intrigued. I don't know enough about the technical aspects to separate marketing chaff from substantive wheat, but they argue that their approach to drop weight gives a more accurate constant pull than even an electronic constant pull device. One person on one thread put it this way (and I'm paraphrasing, so apologies to the original poster): the Stringway stops pulling when it senses the string has stopped stretching, whereas an electronic constant pull stops stretching when the machine THINKS the string has stopped stretching. Those are, he says, not necessarily the same thing.

intuitively that makes sense, and I've read a lot of nice reviews about the Stringway units.

one of my choices is between buying a used Neos 1000 at a pretty good price and putting a Wise device on it, or buying a new Stringway with the stand. Total cost for each option is about the same.

this is one of those subjects that the more I research it the more confused I get.

41. ### TennishackerProfessional

Joined:
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Don't over complicate things.

There are too many variables to string tension.
Clamps, machine, type of string, stringer's experience, mounting system, stringing method, etc.
Just string, if the racquet feels loose, tension higher.

I'm old school, started on woodies, always strung on a Eketon/Neos.

42. ### fortun8sonHall of Fame

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Most of my clients haven't a clue about CP or LO, or much else for that matter.
Most are willing to accept my advice, but not always.
I was frustrated recently by someone who brought in two racquets for his students and a reel of Babolat Duralast.
He asked me to string them both at 1lb under max and refused to listen to me about the string or the tension.
I did do the crosses 5% lower on the Yonex.
I wonder if all that tape is just to compensate for the wrong string?
So, I had to do a sub-par stringing because that's what he wanted.
It bothers me when teachers think they are racquet techs.
Some are, many are not!
Educating someone like this is an uphill battle!
I feel bad for his students.

Last edited: Sep 4, 2011
43. ### Power PlayerTalk Tennis Guru

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I want to throw a wildcard out there - personality type.

Are you more of a type A person who prefers a faster rhythm and wants to get it done? I think a constant pull benefits me since I am that guy. The reason is because I notice that my timing is pretty consistent..each string stretches around 5 seconds before I get the clamp on..I can hit an easy rhythm since the variable (turning the crank) is gone.

A more relaxed personality could probably crank the same pace for each string, but I know that would be tougher for me..just how I am.

Maybe looking too far into it, but it does seem to explain my much more consistent results on my CP machine.

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I wouldn't have dropped tension on the yonex. Your responsibility as a stringer is first to deliver what the customer asks for, and second to educate when it's possible. My course of action:

"Just so you know, it's been a long standing recommendation to string crosses 5-10% lower on yonex frames due to the headshape. I'm just letting you know that I'm not responsible if there's any structural damage as a result of improper tension selection." [although I don't think it's actually a requirement anymore, just one of those "rules of thumb"s. ]

45. ### fortun8sonHall of Fame

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Thanks DD,
You're right, of course.
I was going by the footnote in the Digest.
This was an unusual case as it was neither his string nor his frame and he was using an arbitrary tension figure. "One lb under max recommended"
My fear is that he will allow/encourage his students to use the Duralast until it breaks! Ouch!
Oh well!

Last edited: Sep 8, 2011
46. ### True GutNew User

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Pull My Finger

If you pull a string or anything else (a chain, a spring, my finger) with a given force, it won't break unless you exceed its tensile strength.
In Irv’s example, the string would never be exposed to more tension than it is capable of holding, and would be sitting there happily unbroken after a year. For example, if the tension setting on the CP machine was 50 lbs, at no point in time will the string go beyond 50 lbs of tension. Its stress/tension is never greater than a string with a 50 lb weight hanging on it for a year would would be. It won’t break. If you still think it will, then imagine setting your CP machine to 20 lbs and leaving it turned on for a few years. Will 20 lbs of tension ever break a tennis string? How about 1 lb? Any of these settings will still pull, stretch, pull, stretch, right? But they won't break the string because the tensile strength of the string is higher than the tension ever applied to it by the stringer. If the world didn't work this way, suspension bridges would fall into the water, and those little plastic seats that hurt your butt on swing sets would be dropping like flies all over playgrounds even if people never sat in them.

47. ### IrvinG.O.A.T.

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^^I think that it is great that you are thinking outside the box. As a matter of fact I love it even though what you are saying I do not believe is true. I am sure you have heard the old saying a chain is only as strong as its weakest link. Well the same holds true for a tennis string. The tensile strength of a tennis string is only as strong as it weakest point. That weakest point is the thinnest point. The tensile strength of a string is directly proportional to the diameter of the string. So if you have a 1.25 mm string that is perfectly round (and the same diameter) from end to end all points are the same and the string may have a tensile string of let's assume 100 pounds.

Assume now you pull that string with 60 lbs of tension. Because the force on the string is lower than the tensile strength the string will not break. Because the string is elastic it will start stretching and continue to stretch as long as the 60 lb force is there (or it breaks.) As the string stretches the string becomes thinner and thinner. As the string get thinner it becomes weaker. When the string gets so thin in can no longer support 60 lbs of tension POP.

If what you are saying is true, the tighter you string a racket the longer the string would last as long as the strung tension is under the tensile strength of the string. If the strings are strung tighter there would be less movement of the strings therefore less friction.

If what you are saying is true, all strings with the same composition would have the same tensile strength regardless of gauge (15, 16, 17, or 18) and everything in between.

Irvin

48. ### True GutNew User

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String cheese.

This is a great thread. Thanks to Irvin for starting it. My 2¢.

Whether you use a LO or a CP stringer, you are putting an accurate, given force on the string at the moment you pull tension. Set either type to 60 lbs, pull tension and immediately measure that tension and both will both show exactly the same result. The difference between the two is that the CP machine continues to stretch the string under that same 60 lb load while the LO machine doesn’t. LO's are one-and-done machines. But whether that makes any difference to your final string tension only depends on your strings, not your stringer. It’s all about the properties of the string as to whether an LO or CP makes a difference to the final tension on the racquet.
I’ll get to the point cause now I am getting hungry. Irvin is right, as usual. The LO will exert the same one-time force on the string with each pull regardless of how long you take between pulls. The result is a consistent loss of string tension (due to plasticity) after the racquet is strung. That consistent loss of tension means your crosses and mains should have very consistent final tension when the strings have time to settle in based on their particular plasticity. A CP machine could cause a more variable loss of tension due to how long you take between each pull. How much all this matters to the final tension is really determined by the strings you are pulling. The more plasticity they have, the more it matters.
If you are obsessed about being consistent in your tensioning from string to string, the LO should probably be your thing. If your aim is getting the final tension as close as possible to the number of pounds on your machine’s setting during stringing, you are in the CP camp (just take your time between pulls or pull twice to minimize tension loss due to string plasticity).

49. ### Posture GuyProfessional

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great thread, thanks to all who are contributing, fun for a relatively inexperienced stringer like me to read.

So what impact does the speed of the pull on a LO/crank machine make? I would think that with a quicker pull (the elapsed time from beginning the pull until the machine 'locks out', the more post-pull tension loss. Conversely, the slower the pull, the less post-pull tension loss. Whether that difference exists at all is one question I have, and if it does, whether that difference is meaningful is another.

I would think that while using a lockout, the goal would be to make my pulls as consistent (with respect to elapsed time) as possible in order to achieve a more consistent output from string to string. True, or am I off base?

50. ### True GutNew User

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Agreed.

We'll have to agree to disagree on this point. As I see it, tensile strength is the point where the string yields - that is, where it suddenly and permanently deforms in a way that weakens the string. This will preceed the break. If the tensile strength is 100 lbs, then by definition, 60 lbs will never stretch it to the point of breaking. i.e. the string will cease to stretch and cease to get thinner before it breaks. In effect, the fact that it won't break with under 100 lbs of tension is the definition of tensile strength. What would tensile strength mean otherwise? If it broke at 60, that would mean its tensile strength is less than 60, not 100. A rubber-band, as an extreme example, won't break if you hang a paper clip on it forever. It's elasticity and lack of plasticity (see my other post in this thread) will resist the weight and keep it from breaking until tension/weight is added to where it's tensile strength is exceeded.

If the string didn't wear from the contact with the ball and with other strings during contact, I'd probably agree with you. But as string meets ball in the same area of the string bed repeatedly, there will be heat, friction, wear, and extreme forces at work at that point. They all combine to weaken the string. This causes a gradual decline in tensile strength. To use your analogy, it creates a weak link in the chain. A higher tension string will pop sooner in large part because it will exceed this reduced tensile strength during ball impact before a lower tension string does.
BTW, the amount of movement is not the only factor in measuring the amount of friction. When the force between two bodies increases, you get more friction over a shorter distance. Example, sliding a once ounce weight one foot across your floor won't generate as much friction as sliding a 100 lb one one foot across the same floor. The point being, the strings can move less on a tightly strung racquet and create as much friction (aka heat and thus string damage) as a string moving more on a more loosely strung one.

Given a consistent composition, say a monofilament, a 16 gauge string would have a higher tensile strength than an 18. As you stated, the larger cross-section would certainly increase the tensile strength. If I implied otherwise, I didn't intend to.