I am new to stringing and still trying solve some problems. It starts to look quite ok already. However I am still working on one problem and I am not sure how to deal with that - upper part of the racket head getting narrower after the stringing. I am using 6 point hold down machine (Kawasaki something???). Pattern is Yonex 4 knots (crosses - bottom up). I tried different combination of tensions on mains vs crosses. 18x20 lbs makes the head narrower (compared to how it was without strings) by about 4 mm, 18x19 makes bottom half perfect and top part narrow. Even tension makes racket head fatter in the bottom by about 2mm, while top half is still 2 mm narrow. What could be the reason of this unevenness? What can I try in order to avoid the problem? Thank you!
I would: 1. Make sure tension is right 2. When do crossing, start from bottom to top 3. When reach last 3 or 4 top, reduce the tension by 1 or 2 LB 4. Do not loose side support even if they are block your way, unless you have some crossing done in the vincity, you can feel the pressure when you try to loosen it, if you feel much pressure do not attempt to remove side support.
Thanks for the reply! Will try to reduce the tension when going up on crossed next time. Though was hoping I miss something obvious and don't have to variate tension on crosses. What is strange, side supports start to get loose already when I get to the 5th cross from the bottom (I do string bottom to top). That happens even when crosses are at the same tention - even if I end up with lower part of the head a bit wider. Could it be that 12 and 6 o'clock clamps are too tight and don't let the the frame compress when stringing mains and than it will not get back to it's shape by getting narrower on crosses? (seems unlogical). It sits tight between the posts at 12 and 6 o'clock when removing racket after stringing. Here are some photos of the machine, may be it can give some idea. Sorry, for quick photos, hope they are not too bad.
You've done everything right in testing, but I really wouldn't worry about matters of two or three milimeters. I string my own rackets at 30 lb and use top-down, and they routinely come out 2-3 mm narrow at the top (with the bottom at the correct width). Never broken one yet, with stringing nor playing. If the ratio of length to width is the same after stringing as before, I consider my racket strung properly. #3 of gy's points is a very good one.
Thanks! I will not worry too much than, just reduce a bit tension on the higher crosses. Though just realized, since I was drawing outline of the the racket on paper and checking changes in shape using it - 2mm meant on each side which makes it 4mm.
When you do the last couple of mains on that machine the head usualy becomes slightly wider, and when you pull the crosses the head comes back into shape or becomes a tad more narrow. The mounts are practicaly impossible to get 100% tight, that's why it moves. Has never been an issue to me in the past.
Follow up: I figured that racket length and width were keeping the same measurements at one pound more on crosses. However I still didn't like the idea that racket gets wider at the bottom and narrower at the top even though it gets back into shape after couple of days. So, in search of perfect head shape, I decided to do an experiment: start first lower 7 crosses at +2 lbs relative to the mains, middle 7 at + 1 lbs, last upper 7 crosses - same as the mains (in this case was - 22 mains x 24-23-22 crosses). VOILA!!! The racket head shape came out perfectly same as the outline of the racket unstrung (I marked outline on paper before stringing). I was hoping it will be better but didn't think it will be that good. I suspect that's how tensions shift after a few days anyways. What do you guys think? Am I going crazy with this?
No - I do exactly the same, but in reverse (top down): 27.5 mains, 26->30 from the top, then 30 with ECP prestretch for the last five crosses.
