Why do my string jobs break in these locations?

#1
I've been stringing for about 5 years (just for some buddies from the club and myself) and I've had some problems with stringing lately. It's making me doubt my stringing abilities honestly…

I just strung a Head YouTek Graphene Radical MP with a Tecnifibre Synthetic Gut 17. Had no problems while stringing. However my team mate played with it for half an hour when the string broke somewhere IN the frame:





The same thing happened a while back with a different customer, it was the same string though. This time it happened before he even played a ball (probably laying in the bag).



So, what could I be doing wrong? I noticed it's the same string, could it just be a really bad string? Should I check the grommets before stringing if there's something inside that could cut the string or something (like some leftover clay?)? Is it my machine (it's a relatively cheap dropweight, but it's been working for me for over 100 jobs). Or what else could be wrong with my string jobs?? I mean it's one thing if it breaks because of a bad hit or something, but there's clearly something else that's wrong. People never really had any problems with my work until recently so this kind of sucks.

Would really like some advice here, thanks!
 
#2
Could be: 1) Cheap string 2) over-tightening the clamps 3) As you string, the racket tries to shorten a little (happens with Radicals more than other rackets it seems). When you pull it off the stringer, it rounds out a little, putting more tension on the crosses (it should be minimal though). 4) As you mentioned, grommets should be inspected and cleaned prior to stringing

What you could do: Tube the grommet where the break occurs
 
#3
I'd be inclined to rule out the string. If the grommets are not burned through on the outside of the hoop you can rule them out too. So I'd be looking at either the clamps or the string gripper on your tensioner. The latter would be my chief suspect. If it is pinching string, at some point that pinch will coincide with a turning point for the string and when the stars align it's popping time.

Solution: Buy a professional stringing machine if you have paying customers.
 
#4
Have to done these frames before and had no premature string breakage? If 1st time, check the grommets. If not 1st time, did you kink the string as you pulled them thru the frame?

I do not think your gripper would be an issue since if it were, your number of broken strings due to nicks would be very high from the start of your stringing career. Did you tube the grommets when you redid the string job AND was the job OK?

I normally suspect grommets when there is premature breakage. I will 'burn' the grommet hole with a piece of scrap string to remove any rough edges. If there are any edges, you will feel them as you pull the string back and forth. Worse case, tube the hole.

There have been incidents where a reel of string was defective as well as packs. With a reel, you would suspect that rather quickly as a lot of the string jobs would break prematurely. With pack, there's nothing you can do except do the above.
 
#5
No sharp angles. I suspect it's the grommets. How many times have these racquets been strung?
(and who did it?)

Before i restring a racket (and with cheap string i usually give it whirl) that has seemingly broken
prematurely.....I inspect the grommets (not always easy unless it's the throat grommets). Then i mark
the location with a sharpie (which cleans off easily.....usually). Always tell the customer of the concern.

Bad string? I've only ever had that issue with cheap India gut (which i still use).

Clamps? Doubt it. It's hard to mess up synthetic gut. But take a look after you remove the clamp, perhaps there is a burr or something cutting the string? Doubt it though.
 
#6
And OH YEAH!!! i just remembered i had lots of trouble with breakage on the same model.
But it was a more orange overall paint job (abit older i think). Clear grommets. Had lotsa problems, replaced grommets alot.

Not sure about the Babolat. Looks well used, not sure of the model, they all look the same to me
Ha. I bought and sold mine within a few months.
 
#7
I ran into this issue myself a few years back,, on this head.radical racquets also..
never got to solve it (i thought it was shanks at the time),

after several inspection of grommets and greasing the holes(which helped a little, but not entirely), the problem went unsolved,,

Lately ive come across an idea you might wanna try,,, put a small piece of leather in the spot where the strings break,, like "power pads",, this will reduce the sharp turn of the string on that spot..
And before anyone else says it,, I have checked to make sure it was not the clamps, or string kinks..
it really is an issue with the turn/pinch of the string on some of these racquets,,,
im thinking/guessing/hoping the sharp turn will wear down and round off overtime, but untill then, I think it will leave alot of stringers scratching their heads..
 
#8
@struggle
very frustrating issue,,
I remember I would baby the string job when ever I would see that frame come through,, to no avail,,
string broke in same spot, same racquet,,
I also replaced the grommets, even though it seemed like it was not time,,
frustrating part,, had several other players using that same model racquet, with no issue.. :mad:
 
#9
[/sarcasm] Maybe you should find an exorcist because the frames could be haunted? Or have some Holy Water around to wipe down the frame? [/end sarcasm]

What always seems to work is tubing. But it is a PITA. ;)
 

Ronaldo

Talk Tennis Guru
#11
Had this problem with 80s racquets with hard plastic yokes. Thank goodness those racquets are seldom seen. Lemme tell you about stringing Prince More racquets.................................................................................mo breakage
 
#12
Thanks for the replies guys. It seems most of you suspect it's a problem with the grommets. What do you look for when you inspect them? Do you just look for broken/cracked ones? Because I just checked the Radical and there doesn't seems to be anything wrong with the grommets where the string broke (you can see it on the close up pic too).

Some of you mentioned the string gripper. I have actually had a problem with some string slippage from time to time. Cleaning it with some alcohol mostly works in those cases. Maybe I should do it more. How often do you guys clean your grippers?

Solution: Buy a professional stringing machine if you have paying customers.
I only charge a bit more than half of what people would pay in a sports store (stringing is insanely expensive in Switzerland). And I only string for friends from the club, so I think they're fine with me not using a high end machine. I think the biggest difference between different classes of stringing machines is comfort and the time you can save anyway.

Have to done these frames before and had no premature string breakage? If 1st time, check the grommets. If not 1st time, did you kink the string as you pulled them thru the frame?

I do not think your gripper would be an issue since if it were, your number of broken strings due to nicks would be very high from the start of your stringing career. Did you tube the grommets when you redid the string job AND was the job OK?

I normally suspect grommets when there is premature breakage. I will 'burn' the grommet hole with a piece of scrap string to remove any rough edges. If there are any edges, you will feel them as you pull the string back and forth. Worse case, tube the hole.

There have been incidents where a reel of string was defective as well as packs. With a reel, you would suspect that rather quickly as a lot of the string jobs would break prematurely. With pack, there's nothing you can do except do the above.
It was the first time with this particular frame. Before this it was maybe strung once or twice. So not much. I don't think the string was kinked before I pulled it.
 
#13
The grommets look fine in the closeup and besides the strings exit them in a straight line so unless the grommets are worn through or "burned" on the outside of the hoop it is not a grommet problem. Burning is caused by weaving too fast and would be very unusual toward the bottom of the hoop since you don't have a lot of string at that point to build up friction. Unweaving to remove old string also will cause burning.

I am one of the people who mentioned the gripper. I mentioned it because I was experiencing the same problem as you and the solution was to remove the gripper and have the surfaces machined flat and parallel. To this day I keep the gripper lined with paper (I use a bent file card) as an added precaution. And I guess I have to admit that having a professional machine would not spare you this sort of problem, mine is plenty professional and I still had to go through this.
 
#14
The grommets look fine in the closeup and besides the strings exit them in a straight line so unless the grommets are worn through or "burned" on the outside of the hoop it is not a grommet problem. Burning is caused by weaving too fast and would be very unusual toward the bottom of the hoop since you don't have a lot of string at that point to build up friction. Unweaving to remove old string also will cause burning.

I am one of the people who mentioned the gripper. I mentioned it because I was experiencing the same problem as you and the solution was to remove the gripper and have the surfaces machined flat and parallel. To this day I keep the gripper lined with paper (I use a bent file card) as an added precaution. And I guess I have to admit that having a professional machine would not spare you this sort of problem, mine is plenty professional and I still had to go through this.
Can you elaborate how you made the surfaces flat and parallel? Also I'm not quite sure what you mean by having the gripper lined with paper. Maybe take a picture? Thanks for the help, I appreciate it!
 
#15
On the first machine, I had a machinist grind the surfaces down. The pieces which are steel were held on a flat magnetic table and run under a grinding wheel. The first couple passes, only the outer edges of the gripper were getting ground, which is precisely why they were pinching. We continued until the center of the piece was also getting contact.

The second machine I put a sheet of sand paper on a marble table top (a glass table would probably be just as flat) and did my best to achieve the same effect.

Now, all this assumes your machine has a linear gripper with 2 halves. It is the inner surfaces that would need to be ground and you would have to disassemble the gripper to get this done.

The paper looks like this:
 
#17
@10shoe: Thanks for the explanation and the image, I get it now.

I just took apart the gripper for the first time ever. So far I only ever cleaned it with a shoe lace and some alcohol, but it's been a while and I wanted to do it more throughly now. There did appear to be a bit of "dirt" from gripping the strings since I last cleaned it (as you can see in the pic below. I feel like it somehow looks worse on the picture than it really was though...). I just hope this will clear the issue.

 
#18
So the pieces appear to be plastic with some sort of insert with an aggressive coat of abrasive material. Mine were steel throughout with an aggressive pattern machined into them. Note in your picture the accumulations of material toward the outer edges. Indicates curvature. Grinding yours down though does not look promising but you might try using paper inserts if you can find a convenient way to insert and secure it. On my machine I am using double face tape on the top edge of the gripper. In the picture (post #15) the paper is just beginning to curl away from the tape at the leading edge.
 
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#19
Judging by how much the string pulled back after breaking, it appears the tension was immense. When strings break on me, they retreat by ~5 mm max.

Something could have gone wrong with support. It basically kept the mains from collapsing the frame. When removed from mounting, the mains shortened the frame, forcing the sides apart. This would be exacerbated if there was a differential in tension. So, the questions that might help answer this are “was there a differential in tension?”

You can also test the bad string theory. Take a scrap of that string that broke, and pull it at say 100 lbs. watch what happens. Then pull some string you know is good. Basically, bench test it.
 
#20
One more comment: strings that break on me like that — from sitting alone, and near the frame — are natural gut. Your pattern is very reminiscent of that.
 
#21
So the pieces appear to be plastic with some sort of insert with an aggressive coat of abrasive material. Mine were steel throughout with an aggressive pattern machined into them. Note in your picture the accumulations of material toward the outer edges. Indicates curvature. Grinding yours down though does not look promising but you might try using paper inserts if you can find a convenient way to insert and secure it. On my machine I am using double face tape on the top edge of the gripper. In the picture (post #15) the paper is just beginning to curl away from the tape at the leading edge.
Thanks, I'll try your method with the paper inserts, see if that helps.

Judging by how much the string pulled back after breaking, it appears the tension was immense. When strings break on me, they retreat by ~5 mm max.

Something could have gone wrong with support. It basically kept the mains from collapsing the frame. When removed from mounting, the mains shortened the frame, forcing the sides apart. This would be exacerbated if there was a differential in tension. So, the questions that might help answer this are “was there a differential in tension?”

You can also test the bad string theory. Take a scrap of that string that broke, and pull it at say 100 lbs. watch what happens. Then pull some string you know is good. Basically, bench test it.
Interesting observations. The Radical was strung 55/52 lbs (25/24 kg) so not at all unusual though... Don't think I've ever strung more than 60 lbs. It is quite a stretchy string so that might be the reason why it sprung back like that? I don't think the support system is the problem (you mean the mounts right?) , I've never had a problem with that.

One more comment: strings that break on me like that — from sitting alone, and near the frame — are natural gut. Your pattern is very reminiscent of that.
I only ever strung natural gut once and said never again :) Not worth the hassle for me as I'm not stringing professionally.
 

am1899

Hall of Fame
#24
2 different racquets, with nearly the same premature break. If it were me, I wouldn’t make the assumption that the string can’t be the cause. If OP’s technique is solid, I’d be more suspicious of the clamps and or the tensioner marring the string in some way.
 
#25
2 different racquets, with nearly the same premature break. If it were me, I wouldn’t make the assumption that the string can’t be the cause. If OP’s technique is solid, I’d be more suspicious of the clamps and or the tensioner marring the string in some way.
Yeah I can't really trust that string anymore so I don't think I'll use it again, regardless if it's the cause of those breaks or not. I took apart the clamps and the gripper and cleaned them throughly. Also cleaned the starting clamp for the first time in, like, ever. I'll restring the Radical with a different and slightly thicker string and see if the problem persists. I obviously won't charge for it and inform the customer of the issue. I guess I might have to invest in a new machine sometime soon, even though this one has served me well for over 100 string jobs and still does...
 
#26
What type machine do you have? Your problem is not the string or clamps and from what I see it always breaks on the lower bend of the string. The gripper could be damaging the string then the string breaks when that damaged area of the string is looped around the frame.

Looking at the grime build up on the gripper it looks like the string is sliding on one end of the gripper and that is a big problem. My guess is your machine does not have a Diablo or your do not use it. Also the gripper is not at an angle (still guessing) in the direction of the string coming from the frame. The Wise machine had the same issue initially. The gripper was on a parallel plane to the string bed but lower than the string bed so the gripper was constantly damaging strings. Make a short video of how you mount the string in the gripper and pull tension, that may help a lot. Get a second person to hold the camera / phone to hold camera steady and get fairly close up.
 
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#27
Just as an additional idea based on pure guess, check how quickly / smoothly you apply tension to the string. The string always slides a little through the grommets as you start pulling it. From a common sense standpoint, the faster you apply tension, the more likely it is that stress would accumulate in the area where the string loops through the grommet and turns 90 degrees into the hole, and the greater is the risk that it may get damaged at this point. You may have gotten faster with stringing and applying tension after your 100 jobs, and strings may not like that.
 
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