Why is contant pull so desirable vs. cranks?

[Wondertoy]

Why is everyone so hung up on the need for an electronic tensioner to be constant pull whereas they are fully happy with a lock out crank machine? It appears that most stringers on this board use a crank in spite of the 10% lower tension that it strings at. They fully accept this inferior modus operandi but they then insist that an electronic tensioner be constant pull. Huh? Inexpensive electronic tensioners work faster and pull tighter than cranks but everyone despises them but haven't used them, Go figure.

 

[alan-n]

Its based on the "electric tensioner"'s bad reputation. I'm not sure about recently but in the past these entry level electric motors were of poor quality and reliability. Just like tennis game itself though, its the operator responsible for tuning the clamps and calibration as well as performing the string job that makes the difference.

 

[shojun25]

with constant pull, the string tension holds out better after stringing. or something like that.

 

[alan-n]

with constant pull, the string tension holds out better after stringing. or something like that.

Good stringers are consistent in the time they weave, tension and clamp. Constant pull or not, it does not make up for the skill of that stringer.

 

[156MPHserve]

Inexpensive electronic machines don't make any sense to me.

They may be a little easier to use with the buttons or footpedals but a crank isn't slow by all means.

Electronic machines without constant pull means it doesn't provide a better QUALITY of stringjob.

Cranks work for years and years. Calibration once in a while will obviously be necessary. Worst case scenario you'd have to replace a spring or two.

Electronics however. Who do you go to when you're out of warranty? How do you string when you have a power outage? For a machine with no clear advantage at a more expensive price, the reliability issues are not worth it.

This is why people would rather have cranks. In fact this is why Laserfibre is so popular, due to it having constant pull without the electronics. For those who want constant pull and speed, they'll get an expensive electronic machine. Nowhere does an inexpensive electronic machine fit, unless you're on a budget and insist on going electronic for the sake of it being electronic.

 

[Voltron]

Personally I like my crank, call it "inferior" all you like, I don't care. It's perfect for me, I don't need a $3000 stringer. Nor can I afford one, some of us are only in our teens on this board, get used to the fact that not everyone is a rich as you. /end rant

 

[rjkardo]

Why is everyone so hung up on the need for an electronic tensioner to be constant pull whereas they are fully happy with a lock out crank machine? It appears that most stringers on this board use a crank in spite of the 10% lower tension that it strings at. They fully accept this inferior modus operandi but they then insist that an electronic tensioner be constant pull. Huh? Inexpensive electronic tensioners work faster and pull tighter than cranks but everyone despises them but haven't used them, Go figure.

What I find interesting is that, back in the day (early 80's) it was said that you had to set the electronic stringers several pounds looser because they pulled tension differently. Now, people say that the crank needs to be set tighter.

Either way, the simple fact is that consistency is the issue.
I have strung on all 3 types, drop weight, crank and electronic.

You learn to set the tension per the machine and the clients taste, and do the string job carefully, and you will have a satisfied client.
The type of machine does not matter much. All 3 will do a good job, as long as you know where to set the tension and string carefully.

If you always string on the same machine, you will know what your clients like and be able to match it.

Rod

 

[volusiano]

I wouldn't say inexpensive 'electronic' machine. It's really inexpensive 'electric' machine.

The difference is that expensive 'electronic' machine implies processors and sensors and complicated components and circuitry to monitor and adjust to a desired constant pull.

But the cheap electric machine is simply a motor with some crude circuitry and adjustment to control the amount of current through it to achieve the desired tension. But it is subjected to many variables, the voltage on the power line, which may fluctuate; the temperature of the motor, which starts out cold but then warms up. Not to mention the dependency on having power, the age and quality and wear and tear of the motor/electrical parts, overheating, the ambient temperature (winter vs summer), etc. And finally replacement parts that may not be around any more in a few years.

So why would you want a cheap 'electric' machine instead of a simple quality manual crank that can be just as fast or almost as fast, with very little things to go wrong? And the cheap electric machine is definitely not constant pull. It's probably not accurate as the manual crank either because of all these variations it's subjected to.

Now the Laser Fibre manual constant pull vs the expensive electronic constant pull is a different comparison altogether. The trade off is simplicity for the niceties of all the bells and whistles in the electronic constant pull machine like prestretching, memory settings for different customers, speed, quick or pre-programmed variation of tensions during a string job, etc.

But back to the title of the OP, which is actually "constant pull vs crank". This is an entirely different discussion than "cheap electric machine vs crank", which is actually what's being discussed here.

 

[Mr. Blond]

Why is everyone so hung up on the need for an electronic tensioner to be constant pull whereas they are fully happy with a lock out crank machine? It appears that most stringers on this board use a crank in spite of the 10% lower tension that it strings at. They fully accept this inferior modus operandi but they then insist that an electronic tensioner be constant pull. Huh? Inexpensive electronic tensioners work faster and pull tighter than cranks but everyone despises them but haven't used them, Go figure.

Actually, things are kind of mis represented. The idea of constant pull is that the machine will pull the exact same tension every time (becuase they use load cells to measure the reference tension). The cheaper electronic stringers work off of AC current (and lock out when reference tension is reached), and that causes fluctuations with each pull based on the amperage going into the AC motor when the pull is made. The better electronic tensioners use DC motors which are not affected with variances in amperage. So to say that people obsess about constant pull is not really the case.

Cheap electronic tensioners generally do not produce as consistent a bed as a crank can because of amperage variances. Some electric machines do not use load cells and constant pull, but instead use a spring and a lock out, which is much like a crank. These machines produce great results even though they are not truly constant pull. The reason they do so well is because every pull reaches the correct reference tension.

Its all about consistent string beds, lock outs can do the job, provided, they reach the same exact reference tension on every pull.

I hope this helps the confusion.

 

[fastdunn]

There are many handles of variables where you need consistency.
Constant pull is just a way to remove that one variable.

With alock out machine, I think you need a bit more effort to
find a right reference tension when you string a "new" string.

 

[chrisplchs]

Crank, although nice and get the job done, just aren't as consistent as high end electronic machines. Unless you turn the crank at exactly the same speed with the same angular acceleration and velocity and from the same position, there will be minute differences in each strings tension. Thats why crank's are "inferior" to some electronics. I learned on a crank and I still use a crank sometimes when I am at work. I would take a crank over any kind of cheap electronic machine (by cheap, it is relative).

The whole issue of constant pull and lockout is just another matter of consistency and variables. Once you lockout on a crank, the string loses tension until clamped. The constant pull keeps making certain that it is at the refernce tension until you clamp.

A majority of the people can't tell the difference between the two.

Also somebody mentioned about relability of electronic machines considering the possibility of power outages, etc. I don't live in California under Gray Davis so that isn't something I really have to worry about. Electronic machines are just faster and more user convienent. I don't have to drop a lever. I don't have to turn a handle. I just push a button. Also, I have a nice back up machine that doesn't use electricity incase all hell breaks loose.

 

[Wondertoy]

...The better electronic tensioners use DC motors which are not affected with variances in amperage...Cheap electronic tensioners generally do not produce as consistent a bed as a crank can because of amperage variances....I hope this helps the confusion.

The cheap ($270 and $225) electronic tensioners made by Eagnas and Mutual Power are DC motored, ok?!

 

[Mr. Blond]

The cheap ($270 and $225) electronic tensioners made by Eagnas and Mutual Power are DC motored, ok?!

you are right, they are dc motored, but they also lack in tye type of lock out and also the comutator that regulates the dc motor. There are few electric tensioner that measure up in my humble opinion......just do a search, there are plenty of posts about cheap electrics and inconsistant pulls.

 

[SW Stringer]

. . . Once you lockout on a crank, the string loses tension until clamped. The constant pull keeps making certain that it is at the refernce tension until you clamp. . . .

The millisecond that a crank machine reaches the reference tension it locks the rotor (crank handle is attached) and the string length is fixed. It's the distance between the far grommet and the string jaws of the tension head. Any tension lost in the string segment is due to string "creep" - the slipping of the covalent bonds between the long strands of hydrocarbon chains. Once you clamp the string inside the racquet frame additional loss occurs with the clamp drawback which changes the string segment length, but this occurs with either system, lockout or CP. Most of the drawback is recovered on the next pull in either system.

On the CP machines once the reference tension is achieved, the controlling force (electronics,etc, gravity, spring) is maintained (nearly) at the reference tension, but since the string has viscoelastic properties (it stretches due to bond slipping) the outside diameter of the string continues to decrease and the length of the string segment between the outside grommet and the string jaws increases until you clamp the string off in the frame. If one were able to "quick clamp" on a CP machine the millisecond reference tension was reached then resulting string bed stiffness would be no different than a lockout machine.

The molecular bond slipping that causes "creep" is the most rapid as the reference tension is reached and drops off dramatically to virtual equilibrium in the next 60 seconds. To maintain consistency on a CP you need to clamp the strings repeatedly at the same time interval after reaching reference tension, otherwise the string segment diameters will vary from pull to pull.

The reason a CP machine makes stiffer stringbeds is because you're stringing your racquet with smaller diameter string as compared to a lockout machine - all else being equal, string type, reference tension, frame.

The book "Physics and Technology of Tennis" has some good chapters on string properties. TW carries it. It's a good read which I recommend.

 

[Wondertoy]

you are right, they are dc motored, but they also lack in tye type of lock out and also the comutator that regulates the dc motor. There are few electric tensioner that measure up in my humble opinion......just do a search, there are plenty of posts about cheap electrics and inconsistant pulls.

blabit, I've searched this forum to death. Almost all the negative opinions about the Eagnas and Mutual Power electronic tensioners were from people who have NEVER used them. Are you one of these people? I challenge you to do the search yourself.

 

[Masamusou]

blabit, I've searched this forum to death. Almost all the negative opinions about the Eagnas and Mutual Power electronic tensioners were from people who have NEVER used them. Are you one of these people? I challenge you to do the search yourself.

I have negative things to say (and have said them in the past) about the Mutual Power "Electronic" tensioner (from personal experience I will add) and I stand behind all my previous comments made about it. It's true that a lot of people like to use what other people say about things as their experience, or they like to rip on something just because it is cheaper or whatever their reason may be. I don't see that as the case with blabit but it really doesn't matter.

Why is there such a ridiculous dependence on this board that if everyone else doesn't agree with you that you have to fight them to the death and act like they are personally attacking you? Not everyone likes the same things. A huge number of people on this forum think the Neos is a great machine, personally, I string plenty of frames on it every week and I hate the damn thing. If you don't want to listen to the responses from other people, why bother asking? Is everyone that insecure that they need the support of others to justify their own decisions? If you like the tensioner, why does it matter so much what other people say about it? Just be happy that it works for you.

 

[Wondertoy]

Masamusou, you are one of maybe 3 people that actually had any experience with this tensioner on this board. That is a very small percentage of the people that have made comments on this product. I've read your past comments. The only negative that you said was not on the tension accuracy but that you thought it was not a constant pull machine. I had asked follow up questions on your threads but you never responded. I'm not fighting anyone, I'm only reflecting hands on experience vs. non-experience opinions. Sure, it's not perfect, but it's cheap and does the job. Alot of personal stringers need an affordable machine without spending over $1000 let alone $3000.

 

[Wondertoy]

I have negative things to say (and have said them in the past) about the Mutual Power "Electronic" tensioner (from personal experience I will add) and I stand behind all my previous comments made about it. It's true that a lot of people like to use what other people say about things as their experience, or they like to rip on something just because it is cheaper or whatever their reason may be.

Masamusou, I just reread what you said about the Mutual Power tensioner and you appear to be more positive than negative:

I will be sure to cover the (Mutual Power) tensioner, for an idea of what I think of it, I pulled tension on a string using my calibrator and let it "stretch" for 5 full minutes. The reading lost a total of 3 pounds over 5 minutes. I didn't watch it directly to see if it repulled, but if it only loses 3 pounds over 5 minutes, I'd say that's pretty good. Calibrating is easy on this thing also, you just use a hex key and turn a small screw on the side. Mutual Power does sell the Tensioning unit, I believe it's $225 plus shipping.[

wonder_wall, the (Mutual Power) tensioner consistency is no problem. Once I had the machine set up and ready, I hooked up the calibrator and pulled tension on it 20 times. Set at 60 pounds again, and the tensioner pulled at the reference tension each time. That was something I forgot to mention in the original review.

Is it possible that you have forgotten what you had said? Have you become biased by all the stuff that you have "read," haha! It's good that you will, "stand behind all my previous comments made about it." Don't get to uptight, and don't take stringing so seriously, haha.

 

[Masamusou]

There are a few other problems that aren't mentioned in those because they were in previous threads that were then taken down due to the complete ******** responses I received for them. I don't feel that I need to defend a previous machine. Fine, you want the negatives I experienced. My tensioner never repulled, even after leaving it at tension for an hour. It always kinked poly no matter what. It would occasionally shred the outer layer off of any string. It would never stay calibrated for more than 3 or 4 frames. The tensions that it would pull would occasionally vary by a couple pounds up and down. By the time most of these problems showed up I had already put my previous comments that you searched up here. If you would like I will go back and amend my previous threads to exclude premature experiences. Maybe I got a bad tensioner, don't care the reason, it's not perfect and everyone can make their own decisions (well, maybe not some of the posters on these boards).

 

[Wondertoy]

Fine, I remember emailing you about this tensioner and also asking for further elaboration on threads you initiated about this tensioner and you NEVER once responded. I started a thread 2 months ago, "I need an affordable tension head" and even quoted your comments in that thread and you NEVER once commented. NOW, you finally get on my case tearing into me about needing support from others? You know, you would have been more helpful if you had simply responded months ago before when I was evaluating whether or not to purchase. You were the ONLY one with user experience on this tensioner but for whatever reason you weren't helpful. Albeit late, thanks for your current update. If I had known about your previous negative comments, I probably would have purchased the Eagnas or Wise tensioner. I have only had it a short while and I am still evaluating. I have not had the shearing problems that you have had and I string PolyStar Energy, Poly Plasma and Natural Gut. I don't string as much as you do but so far it suits my purposes.