constant pull crank and dropweight

[Tennis Ball Hitter]

I've been looking at stringers lately and I stumbled upon this constant pull and non-constant pull thing and have only just understood the difference ... I think.

Constant pull, like a drop weight which is constantly pulling the string at a predefined tension [because gravity is always acting on the arm/weight].

not constant pull, a crank, where the tension is pulled and then the string is just held.

I read that there are discrepencies between the two and something about good stringers will ask what tension you want and what type of machine you used previously.

What I don't understand is why there is a difference.
ie with the crank (non constant pull) machine, the only reason for a different tension to the one that it was locked at would be due to the string stretching and thus possibly having a different tension.

If this is the case, then does that mean with a dropweight machine, the arm will not stay level for long and will constantly "fall" below level. And the stringer would then have to adjust the tension as late as possible?

[just trying to make a more informed decision before I select]

 

[Gaines Hillix]

We are talking seconds between the time the arm reaches the level position or the crank machine stops pulling and the time the string is clamped off. During this time the strings starts to lose tension on the crank machine. This is referred to as creep. The difference is about 10% in stringbed stiffness. There are other factors such as the clamping system. Many drop weights use flying clamps and they also lose tension due to twisting, so the real difference may not be 10%. It's not normal to leave the string under tension on a drop weight until the arm drops below level, but if it did it would be correct to raise the arm back up and re-level it. You wouldn't want to do this on some strings and not others in the same racquet. You'd end up with an inconsistent stiffness across the stringbed. Constant pull has become the standard for professional stringing, but you can adjust a crank machine's set tension by 10% to compensate if you have a crank machine and a customer has been used to having their frames done on a CP machine.

 

[fantom]

I believe you understand the dilemma.

As you said, a crank machine pulls to the tension and then just holds the string. During the amount of time from crank lockout to clamp-off, the string will stretch. If the stringer uses a consistent technique, approximately the same amount of post lockout stretching will occur on each pull.

With a drop-weight, multiple string pulls usually have to occur to get the bar to rest near horizontal. The number of pulls a stringer needs to reach horizontal is greatly dependent on the experience of the stringer. These multiple pulls will perform some pre-stretching to the string. After the correct tension is reached (horizontal bar), there will be a certain amount of time before the stringer clamps the string. During this time, the string stretches and the tension head compensates for the stretching by continuing to pull. As the string stretches, the bar will slowly drop below horizontal, which will result in a final tension SLIGHTLY below the intended tension. The longer the stringer takes to clamp off, the lower the pulled tension will get. The bar will also be slightly off of horizontal from pull to pull, which is another variable. This difference will be less than 1 pound, I believe, if you get the bar to within something like +/- 10 degrees.

If you read the boards a little bit, you'll read about another type of drop-weight designed by LaserFiber. These drop-weights remove two of the variables mentioned above. They don't need to rest at horizontal to pull the intended tension. This means that multiple pulls aren't needed and the pulled tension stays exact up until the time you clamp. Different amounts of stretching will still occur, however, if the stringer takes different longer for some pulls than others.

You just have to decide what suits your needs (speed, price, personal preference) and go with it.

One last point is that drop-weights come in two flavors. Ones with great frame mounts and clamps (fixed), and then ones with lesser mounts (2 point) and clamps (flying). Its always better to buy the ones with good frame mounts and fixed clamps.

This is probably the hottest topic on this message board. You'll find a wealth of good information (and some not so good) on this topic.

 

[GuyPerez]

Gaines,
That "customer" would be ME. I just switched to an upright Alpha crank from a tabletop dropweight and I am feeling the difference in matchplay. I usually strung as low as 60 and as high as 62 on my dropweight (my frames). The idea of going up to 66-68 seems outrageous to me. Is this what I should be doing? My crank is new and right on the money calibration-wise.

 

[Mike Cottrill]

Just a wild thought here. How fast do you turn the crank? If you turn slow and hold it a tad just before it locks, humm, what difference you see??
Mike

 

[Gaines Hillix]

Gaines,
That "customer" would be ME. I just switched to an upright Alpha crank from a tabletop dropweight and I am feeling the difference in matchplay. I usually strung as low as 60 and as high as 62 on my dropweight (my frames). The idea of going up to 66-68 seems outrageous to me. Is this what I should be doing? My crank is new and right on the money calibration-wise.

GuyPerez, yea, if you are feeling it in play you should raise the tension on your machine by a couple of lbs. and try that. Keep raising it in 2 lb. increments until you like the way it feels/plays.

 

[Gaines Hillix]

Just a wild thought here. How fast do you turn the crank? If you turn slow and hold it a tad just before it locks, humm, what difference you see??
Mike

Mike, that would create a firmer stringbed if you could control it and be consistent with it along with quickly clamping off.

 

[bigbanger]

I recently purchased an Alpha Apex and started stringing my own racquets, after having used a professional stringer for years that used a Babolat Sensor. My preferred tension on the Sensor was 57 lbs, so I bumped it up to 60 lbs. (+5%) on my Apex and I don't notice any difference in the feel of the racquet during play. In fact, I thought that it actually felt a tiny bit stiffer when strung on the Apex, but that just might be my imagination.

-- bb

 

[wonder_wall]

I've been looking at stringers lately and I stumbled upon this constant pull and non-constant pull thing and have only just understood the difference ... I think.

Constant pull, like a drop weight which is constantly pulling the string at a predefined tension [because gravity is always acting on the arm/weight].

The standard answer you get to this question is string stretch, which is a valid point, but there are other issues, I've never seen anyone delve into all of these, including on the USRSA site where they compare crank and constant pull machines and they only mention string stretch, similar to the treatment you've been given here...

But I'll give one example: First main clamped, crank versus constant pull machine.

Let's take the sequence of actions. Strings laced through two center mains, clamped on one side, tensioned on the other. Tensioned string clamped. Now you have first clamp and second clamp. Now, you go back to the main on the side with the first clamp, you tension it in the crank tensioner, you unclamp that first clamp and then you clamp it higher up the main, closest to the tensioning head.

YOU JUST LOST TENSION ON THAT STRING. Why? Because that 2" or 3" section of string that was INSIDE the clamp was never tensioned. The tension loss on that string is SIGNIFICANT and has nothing to do with string stretch.

I can tell you on my machine, when doing the TENSION, UNCLAMP, CLAMP cycle, I often see the arm pull some more tension after the unclamp step (and note the unclamp step HAS TO come AFTER the tensioning step). If I was using a crank, this extra tension wouldn't get pulled and I'd end up with not such even string jobs.

I test all my string jobs with a stringmeter on EVERY SINGLE MAIN AND CROSS and the maxiumum variance in the main group of strings is usually no more than 3 lbs and much of this is natural (longer strings under the same tension receive less tightness than shorter strings, etc.).

I'd have a much harder time getting that kind of performance out of a crank.

So, not just about "string stretch" and "string stretch" reasons definitely are not the reason I like constant pull. It simply makes it easier to get a nice, uniform string job.

 

[Mike Cottrill]

I'd have a much harder time getting that kind of performance out of a crank.
.

Have you tried?

 

[highsierra]

YOU JUST LOST TENSION ON THAT STRING. Why? Because that 2" or 3" section of string that was INSIDE the clamp was never tensioned. The tension loss on that string is SIGNIFICANT and has nothing to do with string stretch.

That's an excellent point. That 2" to 3" section represents nearly 20% of the string on mains and even more so on crosses. It's 20% not tensioned. wow.

 

[barry]

Just buy a drop weight machine; you get the best of both worlds. No calibration, constant pulls, and save a bunch of money.
Unless you are cranking out 20 or more stringing a week, I would purchase a drop weight machine. You can get the top of the line for around $500, and sometimes less.

 

[bigbanger]

That's an excellent point. That 2" to 3" section represents nearly 20% of the string on mains and even more so on crosses. It's 20% not tensioned. wow.

Isn't it more like ~ 2%?

-- bb

 

[Gaines Hillix]

The standard answer you get to this question is string stretch, which is a valid point, but there are other issues, I've never seen anyone delve into all of these, including on the USRSA site where they compare crank and constant pull machines and they only mention string stretch, similar to the treatment you've been given here...

But I'll give one example: First main clamped, crank versus constant pull machine.

Let's take the sequence of actions. Strings laced through two center mains, clamped on one side, tensioned on the other. Tensioned string clamped. Now you have first clamp and second clamp. Now, you go back to the main on the side with the first clamp, you tension it in the crank tensioner, you unclamp that first clamp and then you clamp it higher up the main, closest to the tensioning head.

YOU JUST LOST TENSION ON THAT STRING. Why? Because that 2" or 3" section of string that was INSIDE the clamp was never tensioned. The tension loss on that string is SIGNIFICANT and has nothing to do with string stretch.

I can tell you on my machine, when doing the TENSION, UNCLAMP, CLAMP cycle, I often see the arm pull some more tension after the unclamp step (and note the unclamp step HAS TO come AFTER the tensioning step). If I was using a crank, this extra tension wouldn't get pulled and I'd end up with not such even string jobs.

I test all my string jobs with a stringmeter on EVERY SINGLE MAIN AND CROSS and the maxiumum variance in the main group of strings is usually no more than 3 lbs and much of this is natural (longer strings under the same tension receive less tightness than shorter strings, etc.).

I'd have a much harder time getting that kind of performance out of a crank.

So, not just about "string stretch" and "string stretch" reasons definitely are not the reason I like constant pull. It simply makes it easier to get a nice, uniform string job.

wonder_wall, not everone uses that sequence. I don't. I won't bore you with the details, but the standard starting sequence you're referring to is used only by hobby stringers LOL...

 

[GuyPerez]

WW,
I release that first clamp as I am tensioning with the crank. With my dropper, I would unclamp and re-pull. Same result.

Gaines,
Please share alternative technique. I am interested in getting better at this.
Thanks.

 

[bigbanger]

wonder_wall, not everone uses that sequence. I don't. I won't bore you with the details, but the standard starting sequence you're referring to is used only by hobby stringers LOL...

Gaines, I'm one of those newbie "hobby stringers" that uses that starting sequence, and I agree that it's not ideal. Can you elaborate on your starting sequence? I'd love to learn a better one.

--bb

 

[Mike Cottrill]

Gaines,
You steped into that one

 

[Gaines Hillix]

Gaines,
You steped into that one

Guys, it was meant to be a joke . I use a starting clamp on the first pull on the center mains. I put it on the inside of the frame on top of the load spreader that is around 1LM when I pull tension on 1RM. Then I clamp off on 1RM next to the frame, thread and tension 2RM and clamp off, then pull tension on 1LM, remove the starting clamp and clamp off on the opposite end of the frame with the machine clamp, then thread, tension and clamp 2LM and then the starting sequence for the mains is complete with the machine clamps sitting next to each other. This totally eliminates the 2 1/2" of string that isn't tensioned using the "standard" starting sequence. You need a good quality starting clamp to do this. Forget the elcheapo ones if you're going to use this technique. Same goes for using a starting clampto start the crosses instead of a starting knot.

 

[ambro]

Yea Gaines, I'd love to hear the better one as well. I think I might know what you're talking about, but I'm not sure. I am sort of a new hobby stringer but I also string for money, so it's not just hobby, and I don't use that starting sequence. I start it with a starting clamp on the inside of the frame on 2L, pull 1L, clamp, pull 1R, clamp, pull 2R, clamp, pull 2L (with the starting clamp still on it), clamp, remove starting clamp, and continue. Is this similar to your method?

Edit: Nevermind, I was writing this before I saw your post. Sounds like we have similar methods.

 

[Gaines Hillix]

Yea Gaines, I'd love to hear the better one as well. I think I might know what you're talking about, but I'm not sure. I am sort of a new hobby stringer but I also string for money, so it's not just hobby, and I don't use that starting sequence. I start it with a starting clamp on the inside of the frame on 2L, pull 1L, clamp, pull 1R, clamp, pull 2R, clamp, pull 2L (with the starting clamp still on it), clamp, remove starting clamp, and continue. Is this similar to your method?

See above....yes, very similar.

 

[bigbanger]

Cool, another use for my new Alpha/RAB starting clamp.

-- bb

 

[wonder_wall]

I use a starting clamp on the first pull on the center mains. I put it on the inside of the frame on top of the load spreader that is around 1LM when I pull tension on 1RM. Then I clamp off on 1RM next to the frame, thread and tension 2RM and clamp off, then pull tension on 1LM, remove the starting clamp and clamp off on the opposite end of the frame with the machine clamp, then thread, tension and clamp 2LM and then the starting sequence for the mains is complete with the machine clamps sitting next to each other. This totally eliminates the 2 1/2" of string that isn't tensioned using the "standard" starting sequence. You need a good quality starting clamp to do this. Forget the elcheapo ones if you're going to use this technique. Same goes for using a starting clampto start the crosses instead of a starting knot.

I'm not getting how this helps.

Unless you've left something out, it sounds like the untensioned string is just sitting in the starting clamp instead of in the machine clamp, which doesn't accomplish anything.

So, I don't see how that helps, but as a crank owner there would be ways you could ameliorate the situation. I was going to mention that you could (1) re-pull that firstly clamped main, or (2) use a starting clamp to ensure that that the segment of string placed into the first clamp IS tensioned. (1) would mean simply that when you unclamp that initial clamp instead of just moving it up to the end of the frame, you move it somewhere, let's just say the same place it already was, and then re-pull, then clamp again at the proper location.

Technically, that still wouldn't perfectly overcome the problem but would get rid of most of it I think.

A starting clamp I believe would be a more complete solution used as follows (this is just my goofy idea): starting clamp OUTSIDE of racket frame, pull tension on that same "problem main" then clamp that first machine clamp in approximately its location using what Gaines calls the "standard" starting sequence. Then dump the starting clamp and from there you would do all the same things but you have a piece of tensioned string in that first clamp.

But I've never heard of crank owners actually using techniques like these.

To the person who said this is a problem on every string, no it isn't because on the other strings you have tensioned string going in the clamp.

To the person who said "isn't it more like 2%" - I think the 20% observation came from the fact that 2.5" would be about 20% of the length of the main that is untensioned.

As I said also though, there are other times during every stringing that I observe the arm pulling extra tension as well AFTER THE UNCLAMP step, but the above is by far the most egregious case.

 

[Mike Cottrill]

I'm not getting how this helps.
.

Wonderwall,
It’s good to see that you are learning . Please look at the method again. No black magic here. Hint: 2 over.. Also, note the use of the load adaptor.
Mike

 

[rich s]

wonderwall, the advantage to a constant pull machine is that when you open/release that first clamp the 2-3 untensioned inches are now tensioned. It's obvious when the arm drops when you release the clamp, that is why I set my arm high on the "problem" string, this way when I release the clamp acting like a starting clamp the arm falls to the horizontal position and not below.

the string would lose tension on a lock out but NOT on a cp machine.

 

[SW Stringer]

GuyPerez says: "Gaines,
That "customer" would be ME. I just switched to an upright Alpha crank from a tabletop dropweight and I am feeling the difference in matchplay. I usually strung as low as 60 and as high as 62 on my dropweight (my frames). The idea of going up to 66-68 seems outrageous to me. Is this what I should be doing? My crank is new and right on the money calibration-wise."

This is where MarcR's Freqness program can come in handy. By measuring the frequency of a single mainstring on your dropweight machine and then duplicating the string length and twidling with the tension setting to match (as close as possible) the frequency on your crank machine you should be able to get a very good match (dropweight vs crank) on stringbed stiffness, without having to string up a bunch of racquets. Of course the devil's in the details. Good luck.

 

[hangzhou]

Mike, Gaines: I am on Wonder Wall's side and couldn't see how the load adaptor could help getting the string within starting clamp tensioned.

According to your other posts, the load adaptos are mainly used to reduce stress on the frame. After you clamp your starting clamp onto 1LM, the string within starting clamp will not be tensioned when you pull 1RM on crank machine. Unless you recrank 1RM again...

Please explain and TIA.

 

[GuyPerez]

1) First R main already tensioned and clamped.
2) As I apply tension to the first L main, but before the crank locks out, I release the clamp on the L main and continue tensioning until lock out.

Is this not OK? The entire string is tensioned. Seems the same as a re-pull on my dropweight.

 

[Brad VanHorn]

1) First R main already tensioned and clamped.
2) As I apply tension to the first L main, but before the crank locks out, I release the clamp on the L main and continue tensioning until lock out.

Is this not OK? The entire string is tensioned. Seems the same as a re-pull on my dropweight.

From a practical perspective, I was taught to do basically the same thing you are doing (and I still continue to do it), although I'm using a Gamma electric (7000 ES) vice a crank-type.

 

[POGO]

Guys, it was meant to be a joke . I use a starting clamp on the first pull on the center mains. I put it on the inside of the frame on top of the load spreader that is around 1LM when I pull tension on 1RM. Then I clamp off on 1RM next to the frame, thread and tension 2RM and clamp off, then pull tension on 1LM, remove the starting clamp and clamp off on the opposite end of the frame with the machine clamp, then thread, tension and clamp 2LM and then the starting sequence for the mains is complete with the machine clamps sitting next to each other. This totally eliminates the 2 1/2" of string that isn't tensioned using the "standard" starting sequence. You need a good quality starting clamp to do this. Forget the elcheapo ones if you're going to use this technique. Same goes for using a starting clampto start the crosses instead of a starting knot.

Nice technique, makes sense in having a consistant stringbed. Will this work using stringers with flying clamps?

 

[bigbanger]

Mike, Gaines: I am on Wonder Wall's side and couldn't see how the load adaptor could help getting the string within starting clamp tensioned.

I don't really see the significance of the load adapter in this technique either. It seems like it would work just as well without it, unless I'm missing something fundamental here (wouldn't be the first time ).

-- bb

 

[rich s]

The load adaptor has nothing to do with it. Gaines uses a load adapter as a matter of preference to distribute the load of the center support over an area rather than concentrate it between the two center mains.

The point of Gaines' technique is to use a starting clamp (with or without the load adapter is inconsequential) immediately adjacent to the frame on the 1L or 1R string so that there is not 2-3 inches of string behind the clamp and in the clamp that will not get tensioned. The starting clamp is only about 3/4" wide compared to a regular clamp and can rest against the frame without robbing the machine clamp (that will clamp the 1st main pulled) of any space when it is time to clamp that string. The whole reason for offsetting the clamp on 1L when pulling 1R is to allow/leave enough room for the clamp when clamping off 1R. When you use the offset clamp method on a lock out machine the string loses a large amount of tension when you release the clamp on 1L from the offest position because the tension head is not pulling on the string and the portion of string behind it is untensioned thus reducing the overall tension of that string. On a constant pull machine (ie drop weights, high end electronic) you don't reduce the overall tension of the string when the offset clamp is released because the string is being constantly pulled by the tension head.

 

[bigbanger]

The load adaptor has nothing to do with it. Gaines uses a load adapter as a matter of preference to distribute the load of the center support over an area rather than concentrate it between the two center mains.

Thanks for confirming that the load adapter is inconsequential here. Isn't the other benefit of using a starting clamp, rather than a machine clamp, on 1L/1R that the clamp will be freely pulled along with the tensioned string during the first pull of 1L/1R so that there really won't be any part of the string that will remain untensioned?

 

[Mike Cottrill]

Thanks for confirming that the load adapter is inconsequential here. Isn't the other benefit of using a starting clamp, rather than a machine clamp, on 1L/1R that the clamp will be freely pulled along with the tensioned string during the first pull of 1L/1R so that there really won't be any part of the string that will remain untensioned?

Think folks think. You almost hit it with your statement above BB. Hint: See your question on the load adaptor .

 

[bigbanger]

Think folks think. You almost hit it with your statement above BB. Hint: See your question on the load adaptor .

We're back to the load adapter again? Dang, Mike, you're killing me here

 

[hangzhou]

Rick: Thanks for confirming the function of load adaptors.

I understand that using starting clamp will eliminate the untensioned slack between clamp and frame, and that can dramatically cut down the tension loss without pull the string again.

However, if you use starting clamp and don't pull 1R again. The string within the starting clamp will cause tension loss of 5.67% at least (assuming clamp 3/4", 1R main length 14", i.e. (3/4)/(14-3/4)). If you have short 1R main, you will have much higher tension loss.

woa... that's 5.67% difference for the two most important strings, i.e. 3 lbs for 60lbs reference tension at least. I am thinking, and thinking very hard, Mike 5.67% plus tension loss at least....

So, if you want avoid that loss, you have to pull the 1R again as pros. Right Mike? I am thinking and thinking hard...

So, if you have pull the 1R again, then, there is no difference between using starting clamp or fixed clamp. Do you agree with me, Dear Mike? lol

Think and think hard, Mike! The load adaptor and starting clamp will not give you better results if you don't pull 1R again on non-constant pull machines.

bigbanger, Mike: we are off with load adapter and starting clamp, agree?

Have fun...

 

[rich s]

the only other thing I can think to do is put the starting clamp on the outside of the frame (not on the loop side side of the frame but on the free end of the string side of the frame) this way the starting clamp is between the frame and the tension head when you pull that string.

then when you pull the string and you clamp the string the starting clamp is still between the machine clamp and tension head and thus no tension loss on the string.

 

[Mike Cottrill]

Okay, here as some more hints.

“rich s” writes: “3/4" wide compared to a regular clamp and can rest against the frame”. What is it resting against? Isn’t there something between the starting clamp and the frame on most sticks? .

“BB” writes “clamp will be freely pulled along with the tensioned string”. What does stops it from moving freely on most frames?

When I mentioned the load adaptor, it had noting to do with tension loss.

Gaines is smart fellow ..

Side issue:
What friction coefficient are you using for all the percentages? Fun Fun stuff. Need something to break up this work day.

 

[bigbanger]

Okay, here as some more hints.

“rich s” writes: “3/4" wide compared to a regular clamp and can rest against the frame”. What is it resting against? Isn’t there something between the starting clamp and the frame on most sticks? .

“BB” writes “clamp will be freely pulled along with the tensioned string”. What does stops it from moving freely on most frames?

When I mentioned the load adaptor, it had noting to do with tension loss.

Gaines is smart fellow ..

Side issue:
What friction coefficient are you using for all the percentages? Fun Fun stuff. Need something to break up this work day.

OK, so it sounds like the load adaptor is there simply to provide an even surface against which the starting clamp can be pulled against the inside of the frame. Otherwise, the clamp will be pulled directly against the inside of the grommet. Why didn't you just say so?

-- bb

 

[hangzhou]

Rich: Thanks for the suggestion, which I did agree initially, but...

Let me try the sequence, correct me if I was wrong:
1. Clamp 1R on the outside of frame using starting clamp. Tension the other side of 1R and clamp 1R with right fixed clamp.
2. Thread 1L and tension 1L. Clamp 1L with left fixed clamp.
Two options I can think of:
3.a Release right fixed clamp and clamp it on 1R close to frame near starting clamp. Release starting clamp and continue on 2R.
3.b Tension 1R with the starting clamp on and leave the tension unlocked. Release the starting clamp, pull 1R again and lock the tension head. Release right fixed clamp and clamp right fixed clamp close to frame. Continue on 2R.

I would prefer 3.a, which one will you prefer? Do you have better approach than these two?

TIA

 

[hangzhou]

Side issue:
What friction coefficient are you using for all the percentages? Fun Fun stuff. Need something to break up this work day.

No need to bother friction coefficient here.

The starting clamp is holding about 3/4" untensioned string, which will have to take some stretch, thus reduce the tension on the remaining string of 1R, that's where the most tension lost come from.

I just want to find out what's the best approach, what the load adaptor and starting clamp can bring, good or bad...

When you use starting clamp inside the frame, then you have to use load adaptor. But there is potential tension lost without pull 1R again.

If you agree with the potential tension lost for starting clamp, then you should agree that using fixed clamp on 1R will produce similar result if everythingelse is same...

 

[Mike Cottrill]

Simple test: When you release the clamp watch the string closely or mark it with a marker next to the clamp, if moves, then you have an issue.. If it does not move, how can you being losing anything? If it moves, then look for a ways to improve.

IMO, the starting clamp is not necessary, but it is nice method. If you do use the starting clamp inside or out, just make sure the frame and the grommets are protected.

Were is Gaines today?

 

[rich s]

Rich: Thanks for the suggestion, which I did agree initially, but...

Let me try the sequence, correct me if I was wrong:
1. Clamp 1R on the outside of frame using starting clamp. Tension the other side of 1R and clamp 1R with right fixed clamp.
2. Thread 1L and tension 1L. Clamp 1L with left fixed clamp.
Two options I can think of:
3.a Release right fixed clamp and clamp it on 1R close to frame near starting clamp. Release starting clamp and continue on 2R.
3.b Tension 1R with the starting clamp on and leave the tension unlocked. Release the starting clamp, pull 1R again and lock the tension head. Release right fixed clamp and clamp right fixed clamp close to frame. Continue on 2R.

I would prefer 3.a, which one will you prefer? Do you have better approach than these two?

TIA

I was thinking something like this:

1.attach the starting clamp to 1L on the outside of the frame on the free end side NOT the loop side.
2.pull 1R and clamp w/machine clamp.
3.pull 2R and clamp w/machine clamp
4.pull 1L and clamp w/machine clamp, remove starting clamp.
5.pull 2L and clamp w/machine clamp.
6.continue pulling mains alternating side to side.

 

[wonder_wall]

Simple test: When you release the clamp watch the string closely or mark it with a marker next to the clamp, if moves, then you have an issue.. If it does not move, how can you being losing anything? If it moves, then look for a ways to improve.

IMO, the starting clamp is not necessary, but it is nice method. If you do use the starting clamp inside or out, just make sure the frame and the grommets are protected.

Were is Gaines today?

Well, I've been reading the exchanges with some interest and I must say thanks to you Mike even if your responses were rather sphinx-like (and irrelevant).

But anyway, Mike, I'm still not seeing where the technique helps with the problem identified, and yes, THIS IS A PROBLEM ON CRANK MACHINES, and yes the way of calculating the percent of untensioned string by "highsierra" is correct for that "problem main," lack of friction coefficients notwithstanding.

Regarding that 20% of highsierra, which I thought I already explained once to those who didn't understand what he was saying, when I made the original post I said 2" or 3" in the clamp. That was just because I didn't know exactly what my clamps measured, so I was just guessing - this is actually a fixed number. I just measured my clamps and they're actually 2" long almost exactly, probably everyone elses are nearly the same. I just measured a center main on a racket at 12.5". Hence by highsierra's logic, it would be 16% of that "problem main" string that is untensioned ON A CRANK, he used 2.5" so he got a slightly higher number. If a starting clamp is 3/4" long, it's still 6% of the string untensioned, admittedly better but still NOT GOOD and not at all completely addressing the issue.

hangzhou: Thanks for sticking in there with the point even though the consensus was (heck, probably still is!!!) against us.

Rich S: Yes, of course, this is not a real problem with constant pull machines, or at least it isn't with mine (a further analysis of the extent of a "residual problem" I can think of on constant pull machines might be interesting....).

AMBRO: I believe your technique may be the best pointed out so far - BUT, HOW DO YOU PROTECT THAT GROMMET AT 2L? Do you use something like the load spreader to have the starting clamp up against?

I believe Mike was making these paradoxical responses in order to inform us that the load spreader allows use of the starting clamp on the inside of the frame instead of on the outside. Mike, is that right?

That may or may not be a useful trick, but it's not terribly relevant here.

rich s and hangzhou: As far as technique, I think you still need a little help, in addition to ambro's method, which seems excellent to me once the problem with protecting the 2L grommet is handled, I already also pointed out my idea, which restated to work on any racket, even ones where the starting clamp won't fit on the throat side, would be this:

1. starting clamp on outside of frame and on head side of 1LM,
2. pull tension at throat side of 1LM,
3. clamp machine clamp in its position for what Gaines calls "standard starting sequence."
4. release tension from tension head and release starting clamp and just continue stringing THE WAY YOU ALWAYS DO after you do that first clamp.

This is essentially what I already described as a solution using a starting clamp, but here it's reorganized slightly to work with any racket, even ones where there's no space for the starting clamp to sit in the outside position on the throat side.

As you can see, the simple idea is to use a starting clamp to help you get the initial machine clamp into its initial position with TENSIONED string in it instead of UNTENSIONED. Then the rest is just the same as the standard starting sequence (which I also already described in my initial post here).

The only difference in the above for different rackets is at (3) you either clamp at the head side if the "loop" is on that side or at the throat side if it's on that side.

In addition to working with any racket, it also doesn't require a load spreader to put the starting clamp up against, because the starting clamp is in its more typical position outside the frame. In fact, I don't think you can overcome the problem with a load spreader because the clamp would need to go on 2L (or 2R) if it's inside of the frame, and I believe this load spreader thing is made to only go in one position, right in the center (and even that doesn't work on all mounting systems).

I think Mike you settled on essentially this method I had previously described as well, but the above is just a slight restatement of what I had previously said, just so the tensioning steps are the same on any racket and will work on any racket, even rackets without space for a starting clamp at the outside on the throat side.

 

[hangzhou]

Mike: The untensioned string will cause string to move. Just a mental experiment can prove that, while pratically other guys have the sequence to recover the tension loss. I agree with you the starting clamp is a nice method, but not the neccesary one since there is not much gain. Maybe Gaines has something that we don't know of.

Rich: You approach looks easy and simple. That's great and I will use yours...

Wonder Wall: In your approach, step 3 and 4, will you clamp both your right and left fixed clamps on 1LM at same time? My machine (ECO with fixed clamp) cann't do that. I bet your TT cann't do that neither. The arm on these fixed clamps are not long enough. I don't know whether other type machines have such capabity. I believe Rich's approach much straight forward and fast.

Thanks for sharing your methods anyway. Have fun, gentleman...

 

[wonder_wall]

Rich: You approach looks easy and simple. That's great and I will use yours...

Wonder Wall: In your approach, step 3 and 4, will you tension both your right and left fixed clamps on 1LM?

No, of course not, step (4) is just release the string from the tensioning head and release the starting clamp, leaving SLACK STRING ALL AROUND EXCEPT FOR in the FIRST machine clamp (which you clamped in between the tensioning head and the starting clamp) - remember, that is the problem you're trying to fix, slack string INSIDE the machine clamp. From there, you just string as usual.

Rich's approach has the "unpardonable sin" of tensioning two strings at the same time. Not what you want, and certainly another tension killer.

But, Hangzhou, you have an ECO? If so, you don't personally need to bother with any of this. I brought this up on the subject of "crank versus constant pull." You already have constant pull, you don't have a particular need to do any of this.

This is FOR CRANK OWNERS.

All this stuff is what I consider a useful exercise in examining how you can get the same job out of a crank machine as you get from a constant pull machine.

I would strongly advise crank owners who care about their output to fix the problem here being described, and so I'm actually prescribing some solutions.

P.S. The starting sequence that Gaines pretended to ridicule or did ridicule (I'm still not clear on what his "joke" was) is FINE and it is UNIVERSAL and it is just nonsense to say it's only used by hobbyists - are you still thinking that you for some reason need a better starting sequence because Gaines said this? It was either a joke or just plain nonsense.

 

[Mike Cottrill]

Wonderwall,

Yes “I think”. When I jumped in, it was just for the purpose of the load spreader in Gaines’ description.. To use it as resting place for the starting clamp (protecting the grommet). Sorry, I was just having a little fun with that to see if any one noticed that he keeps the SC off the grommet (not trying to be jerk). I’m looking for ways to protect the frame similar to you looking to eliminate unnecessary tension loss .

As for the tension loss, I actually did not read or follow it closely to until now. (I have a hard time with long posts.. I guess I have ADD). I just picked up the part about “I'd have a much harder time getting that kind of performance out of a crank.” I do see your point about the section of string in the clamp. But give this a try, set your clamp tighter than normal, get a scrap piece of string and place it in the clamp (a synthetic gut 16g will do like prince syn). Take a marker/pen and mark the side that will not be tensioned next to clamp. Then put a mark on the string by each clamp tooth including the outside one that will be tensioned. Set the tension to ~72lbs and pull. What do you notice with the marks?

Man, it is late and I’m tired and probably not making any sense. Anyway, lets keep this thing going. We need to get Gaines back in this . Lets all keep learning. That how we all make progress and improve. Man how am I going to play at 9am..

 

[hangzhou]

Wonder Wall: you lost me this time. After step 3, you have left fixed clamp on throat side of 1LM, right fixed clamp free and starting clamp outside frame on top 1LM, tension head locked 1LM, right? In step 4, you release tension head, and then the starting clamp. Now you have only left fixed clamp on your 1LM, right? Where is your right fixed clamp and tension head now?

Maybe Gaines has something that we really don't know, so stay cool...

 

[wonder_wall]

Wonder Wall: you lost me this time. After step 3, you have right fixed clamp on throat side of 1LM, left fixed clamp free...

No.

Looking at my step (3) I guess I didn't say which clamp I was using, I thought that would be obvious, so here it is INCLUDING that it's the LEFT clamp (as you say, you couldn't use the right clamp for that so I really don't know why you're assuming I'd be using that one). I'll also extend the steps a little to include things in the regular starting sequence, this should make it easier to understand:

1. starting clamp on outside of frame and on head side of 1LM,
2. pull tension at throat side of 1LM,
3. clamp LEFT machine clamp on 1LM string in the location for THIS CLAMP to be the initial clamp of the "standard starting sequence."
4. release tension from tension head and release starting clamp and just continue stringing THE WAY YOU ALWAYS DO after you clamp that first clamp.

The above is intended to be generic for both head loop and throat loop

Now here's a FULLER THROAT SIDE LOOP version, to make this more understandable (notice 1-4 are essentially identical to the above, only (3) is different IN THAT IT SPECIFIES THE LOCATION WHERE YOU ARE CLAMPING [head end or throat end]):

1. starting clamp on outside of frame and on head side of 1LM,
2. pull tension at throat side of 1LM,
3. clamp LEFT machine clamp on 1LM - THROAT END.
4. release tension from tension head and release starting clamp.
-- FOLLOWING STEPS ARE THE "SAME AS ALWAYS" ONES --
5. pull 1RM
6. clamp 1RM at head end with free right machine clamp.
7. pull 2RM, throat side.
8. unclamp right clamp and move to 2RM, throat end.
9. pull 1LM (WITH TENSIONED STRING IN THE CLAMP - PROBLEM SOLVED!)
10. move left clamp from throat end to head end of 1LM.
11. pull 2LM
12. move left clamp from head end 1LM to throat end 2LM.
13. DONE. START SEQUENCE COMPLETED now clamps are at 2LM and 2RM, repetitive stringing from there....

The order of the "same as always" steps 5-12 is not particularly important - other than keeping your clamps out of each other's way, but the above is an example.

 

[wonder_wall]

Wonderwall,

Yes “I think”. When I jumped in, it was just for the purpose of the load spreader in Gaines’ description...

Thanks for the update Mike.

I don't have a racket to string right now, but I wouldn't mind trying your marker thing, especially if based on the marks we can compute exact numbers on things (which I believe we could) but I can tell you there is definitely VERY significant tension loss, it would be less with the starting clamp of course as already stated, but still would be significant...

 

[hangzhou]

Wonder Wall: I made a mistake in my last post and fixed it now. But you don't need to read it anymore since I got your idea now. The key is explained in step 9(WITH TENSIONED STRING IN THE CLAMP - PROBLEM SOLVED!). Thanks a lot, my friend. But you pull the 1LM twice... lol....