hey guys, i have been stringing rackets for quite a while now. i use a 6 point electrical pull machine and never had any problem until yesterday. while i was pulling the second to last cross string, the main thru hole a3 snapped and the racket broke at where hole a5 is (see pix). i had string break during stringing before but nothing ever happened to the racket. i do however always noticed that whenever i get to the last 3 cross, the top of the rackets do shifts a little like the shoulder supports are not tight enough. now i have another NS9900 need to get restrung but i am a little gun shy now.i am just wondering if this has ever happen to anyone before? did i do something wrong? should i tighten the shoulder support as i get to last few cross?
It's not that high, it shouldn't have broke, even if your supports are a little bit loose. What I normally do on the last few crosses is when I tension them. i literally push the part of the frame being tensioned back the other way so there is minimal movement. But what I really need is a machine with better supports. Haven't broken a racket before. Sorry for your lose though
yeah i know the tension is not that high because i have strung higher tensions before and rackets were fine. thanks for you help anyway. may my NS9900 RIP.
That happened to me once. If you don't cut the main string when it breaks, the frame will warp and then crack. Breaking a main string around that area will cause serious instability on an isometric frame.
Third. The "point" of the iso frame is the most vulnenerable area, so cut your strings IMMEDIATELY they break (and advise any customers to do so as well) - they're no good broke! I once played a 4U AT900P at 32 lbs and broke M5 - the resulting distortion was terrifying (to the point where the coach was ready to commiserate that I'd broke the frame), but swift cutting left it as good as new.
thank guys for your valuable input from your experiences so i know i am the only one this happens to. so is there a way preventing the main string break during stringing or is it just a bad string?
Beware of sharp grommets and sharp tools. Sharp tools include fixed or flying clamps with sharp edges.
Sounds strange, but if you use swivel clamps make sure their "natural" position is BELOW the level of the stringbed i.e. you can slide them around underneath; I did this by cutting down the supplied springs that go between the clamp an its base stem. Before I did this I often "tweaked" the strings while moving the clamps around (never broke any, but why take the chance?).
pulling cross, and the main broke??? very strange! a few comment here: - sharp clamp make a "cut" on the main when stringing the cross string that's close. - OLD string, which is showing its age. as for the frame damage at such low tension, I would also suggest you to check: 1. the calibration of the tension meter. 2. make sure the racket is a real NS9900. I have strung a FAKE NS9900, which showed a LOT of frame movement when I was doing the top few cross strings. very sorry for your loss.
i have never calibrate my machine since i got it but i don't think the tension will be that much off especially i have been stringing with this machine for over 2 years. the racket was definitely a real NS9900 because it was from a very reputable store. i hope this is just an isolated incidence because i still have lots strings i need to restrung. cross my fingers.
Do you string the cross from top of the head down to the throat or vise versa? You may want to start top down.