I am following Yonex pattern (2 piece, Bottom UP) while stringing all rackets irrespective of brands. If I only change it to Top Down, will it make any damage to frame. Will it tend to break the racket while playing?
It won't damage the racquet if you string top down, in fact it is better for the racquet. Obviously this is all assuming you're an experienced stringer and have the right gear.
It depends on the machine to some extent, but all things being equal I would also say top down is safer.
I always thought bottom up was safer because the throat contained thicker material in the frame, bottom up for durability and top down for playability.
The top is one of the most fragile part of the racket. By going top down, you relieve most of the tension created by the mains' force on the top first, so the top goes "back in shape" faster. That being said, with a good machine, it doesn't make that much of a difference because the supports are better.
I see, it does appear to be more safer to tie in the top first. I do Haribito majority of the time, only 2TD if I have broken strings laying around.
As you put the crosses in, the "spreading stress" goes away from them - as you put the top crosses in, the bottom of the frame tries to flare out, and vice versa. It's a question of where you want to spreading stress to go, and the bottom being stronger, I'd send it down there.
I agree with this and still doesn't understand why Yonex is recommending bottom up. Paul www.badminton-coach.co.uk
Just to add to the above. Aside from the "spreading stress" there is also the matter of pulling the frame to one side as you do the crosses. As the frame is stronger near the throat, when you reach the top going bottom up, the frame is already under a lot of stress from all the crosses you have just done. So the theory is, the last few crosses at the top which will tug the frame to one side, at the weakest part of the frame could be risky. Whereas, if you went top to bottom, you are gradually introducing more and more load to the frame as the frame gets stronger - which in theory at least, is better. Having said that, I don't often string top down (as I prefer one piece stringing and have a 6pt machine) unless the racquet I'm stringing is questionable at the tension required. In most cases though, bottom up is fine.
I would guess that Yonex say bottom up because of all the tungsten in the top of the frame on the Voltrics. No idea about other models.
Well, Yonex have always been bottom up way before the all these exotic materials came about. I think they just feel that there's no need to change. But as you say, modern racquets are generally much stronger than they once were so can comfortably take very high stresses/tensions. ArcFB being an exception!
I am thinking the racket head is more flexible towards the top of the head due to it being thinner. So if you string bottom up for crosses then it pushes the stress up the way, the stress spreads more as it gets constantly more and more flexible towards the top of the frame(large area for the stress to go). If you go top down because the head is stronger towards the bottom the stress will bunch up at a point because it's going to a much stiffer area therefore the stress will not spread(small area for the stress to concentrate)
This is the problem: a case can be made either way. What we need is a big survey of broken rackets top-down vs broken rackets bottom-up (but even that survey wouldn't give us what we need because we can't control for stringer experience, racket condition, machine spec...).
The only reason I string top down is because I find it easier to finish threading the crosses and tying the last knot at the bottom rather than the top. (Laziness trumps all arguments of structural integrity!)
Another good point - it's not all about keeping the frame in one piece. If all the structural stuff cancels out, and it's no better whichever way you go, I'd still prefer TD because you can use a starting knot at the top; I'd rather lose tension from the bottom than the top.
I've only strung a couple "bottom up" and it's a nightmare to weave and tie off at the top, it's so much easier going "top down".
I totally agree. The Arc Saber Z-slash is the racket that would frustrate me to no end if i had to string bottom-up.