I found this video of a 'Yonex master stringer'. He does a few things that surprise me. - He double pulls the first two mains, the last two mains and the first two crosses. - skips the 2nd last cross and then comes back to it after pulling the last cross Does anyone have any insight as to why he does these things? Also, what type of knot is he using? [video=youtube;73gzJ9sB9Sc]https://www.youtube.com/watch?v=73gzJ9sB9Sc[/video]
Saves having a string jump from zero to full tension when the stationary clamp is released - a lot of breakages happen at this point. No idea - you're going to lose tension from the knot, so why compound the problem by double-pulling? Could be a remnant from proportional stringing, I suppose. The YY stringers at the All England were doing this - reduces stress on the starting knot (but it's another thing I never do). This is so he can tie off at the second-to-last main instead of A5 (as is usual). Yet another thing I disagree with.
uhhh..he cheats quite a bit when tensioning the mains..lolz still only lil shy of 15 mins cutting so many corners lolz xD
On high tensions i have often the problem, that the string is cutting into the frame (inside) on the last main (even if the grommets are in good condition), because the angle is the sharpest one. So if you string on 29 lbs with 20% prestretch (~35 lbs) the stress on the grommet and frame is a lot. On "higher" tensions (above 24 lbs) i always pull the last two mains... I tried a lot, but above 24 lbs it is the critical limit for some rackets (also yonex after some restrings on high tensions)... For example: Victor Light Fighter 7000 on 24 lbs with 15% prestretch
Makes sense, but I have never had a string pop on those grommets. Those are the areas where the string bends most, though.
Mine - I thought you might have been doing 9-10-12, in which case the stress on that outermost grommet would have been increased even more.
Back to topic: What type of knot is that? Looks not so bad... And: i do this if the tension is also over 24 lbs OR if i (must) make the knot on B7 instead of B6. For me it prevents that the starting knot sunks into the grommet and puts too much stress on the main string...
It might look bad, but providing the grommet is in good condition and well placed, it shouldn't be a problem. Not a lot you can do other than replace damaged grommets here.
I think I'm going to try this double-pulling on the first two mains and see what effect it has on tension loss - if it's minimal (or, preferably, non-detectable), the safety gains will be worth it.
the plucking of the string is odd. it looks like he is trying to see if the tension has settled by listening to the pitch. which makes very little sense for 2 reasons: 1. he is using a protech 8. tension will be spot on. 2. the length of the string isn't constant due to the shape of the racket, the pitch will change slightly. or maybe i am reading too much into what he is doing and perhaps it is just a pointless habit? his weaving is slow. his 14mins string job would've been cut down by another minute if he can weave as fast as @kakinami , @Ah_Shum or Walter. using the thumb going backwards isn't gonna be fast enough, index finger moving forward is much more agile. having said that, there are a few similarities between his pattern and mine. looping back from cross top and the tie off point. the knot is the sausage bun knot that AK has demonstrated before. i really should do a video of my current flow. it has evolved quite a bit since i last made a video!
just to clarify on the weaving. his main weave is fast. sub 5 mins, but the cross is slow. nearly 10 mins. usually the ratio is around 1:1.5, but his is almost 1:2
I don't have fixed clamps (I use a starting clamp outside the frame) so i don't think i have this problem ... but from what i can work out, wouldn't it be better to clamp main a1 at the top, then pull b1 at the bottom (so you pull through the top centre grommets) and clamp. Then pull b2, and move that bottom clamp to the top (now both clamps are next to each other). Finally pull a1, but as the tension head takes up the slack release the clamp so that the entire length of the string gets the prestretch. That way, all of the centre main strings get the same pull, the same prestretch, and (most importantly in my view) are all clamped the same distance from the frame.
This is exactly what I do. Having a knot at B7 makes the main and the knot too vulnerable, so I either double pull or knot at B6 anyways, even if there will be a second knot at the top of the racket on that main. Imo, the benefit of being able to pull every cross is greater than the consequences of having 2 knots on the same main.
Could be he's plucking to get the tension up to target faster, but it also sounded lik he's using prestretch, which would make it even more pointless.