So today i visited the most famous stinger in Russia, his name is Victor Gromov. His was named The Best stinger in Russia by Russian Tennis Federation. Was official sttinger at Kremlin Cup since the very beggining. Gromov was the man that was working with Aslan's rackets during Kremlin Cup-2021. When Karatsev gave his rackets for the first time, Gromov (as he said today) didnt believe his eyes. Aslan asked him to string his racket so the racket would change length and the width of its head! Karatsev was used to play with a racket around 1 cm wider in its head and around 1 cm shorter in its length. Gromov said that it was the first such case in his practise. Thats the story about Karatsev's-2021 racket. I hope this story will be useful and interesting for tennis fans.
If I understand you correctly, Gromov (at Karatsev's request) would mount the racquet into the stringing machine and (using the frame supports) would "stretch" the frame so it would be 1cm wider and 1cm shorter?
I don't see how that is possible: The frame supports on professional stringing machines (Wilson, Technifibre, Babolat) are unidirectional and designed to prevent the racquet from stretching/warping during stringing.
However, all the frame supports are designed to work in one direction.
The two INNER frame clamps - at the top center of the frame and at center of the bridge (12 o'clock and 6 o'clock position) - are designed to PULL.
The four OUTER frame clamps - at about 2 o'clock, 5 o'clock, 7 o'clock and 10 o'clock - are designed to PUSH.
Overtightening all the frame supports would result in making the racquet longer and narrower (the opposite of what you're claiming).
Or, are you saying that Gromov would clamp the racquet in the machine in the regular way and while the main strings are under tension would loosen the inner frame supports (very slowly) and also loosen the outer frame supports so the racquet would contract lengthwise and expand widthwise until it is 1 cm shorter and 1 cm wider?
I have never tried that but it would be possible with the mains. However, I believe that once you start with the cross strings, there's no way to stop the racquet from elongating again. The inner frame supports are designed to stop the racquet from contracting lengthwise but can't stop the racquet from expanding lengthwise. If you used steel cables in the mains (with minimal stretch) you might be able to keep the racquet from elongating lengthwise once you start on the crosses. With regular strings, the pulling force of the cross strings will contract the width of the racquet which will have an elongating effect on the length of the racquet.
Now, if you had a stringing machine with frame clamps that would be bidirectional instead of unidirectional, you might be able to force a racquet into the your desired shape (longer, shorter, wider, narrower) and then string it. I don't know if that would work though as I'm not familiar with the shape memory of graphite/kevlar/twaron etc. as the racquet wants to go back to its "natural" shape.
Also, keep in mind that the above scenarios would have an effect on the string tension: If you loosen the inner frame supports while the mains are under tension (shortening the length of the racquet and expanding the width of the racquet), the tension of the mains will increase once you start on the crosses. As the stringing machine is not designed to stop a racquet from expanding lengthwise (within reason), the increased length of the racquet will apply more force to the mains = higher tension.
Now if you had a stringing machine with two INNER frame clamps at 9 o'clock and 3 o'clock (expanding the width = making it shorter) and OUTER frame clamps at 12 o'clock and 6 o'clock (compressing the length = making it shorter = making it wider) THEN you might be able to make your racquet 1cm shorter and 1 cm wider. However, I've never seen a stringing machine with such a frame set up.
I'm aware that the OUTER frame clamps are positioned so that stringing process limits the lengthwise expansion of the racquet. In order for a racquet to keep its shape, each force needs an equal and opposite reaction force. However, for practical purposes, this is not really possible and in the real world compromises are necessary. The way stringing machines are designed the natural stringing process make a racquet longer (length) and narrower (width) by millimeters not centimeters.
tt.tennis-warehouse.com
