After reading this and this, I thought I can help my BC buddies a little bit Here are my personal opinions: 1. Don't get too concerned about the 4 knots/2 knots pattern. Each one has its own merits and the topic has been discussed to death on this forum. Generally, 4 knots are faster to do where as 2 knots saves more strings, but a good stringer can produce quality stringjob with either of them. There are differences but I believe choices are often personal. The bottom line: The main strings must start from the centre of the racquet. 2. Though an expensive machine will most likely mean better supports, ergonomics and more accurate pulling, a fancy machine itself does not guarantee the quality of the string job. It is the stringer that matters. Having said that, if you want to have your racquet strung at high tension, watch out for those two point support machines. In that case you will need a six point machine to safely support your racquet at high tensions. 3. High price does not necessarily mean a high quality string job. I've seen some appalling strong jobs that charges $30 for labor. Also do not associate attitude with stringing skills, bad attitude does not necessarily mean a bad stringer in terms of skill, just makes a bad businessman 4. Tennis racquets and strings can withstand staggering amount of abuse when compared to badminton counterparts. If your stringer does tennis only and don't know what he is doing it is quite likely that your badminton racquet will be damaged. 5. A good stringer often avoids pre-weaving the whole racquet, as this practice will leads to tension loss due to friction between mains and crosses. Use of awls and string mover (hook) are often necessary, but incorrect use can damage the string and leads to drastically shorted string life. I've seen stringers who wax the strings to make them easier to pass through grommets if you happen to see those people, RUN! 6. Quality string job depends on attention to detail: A good stringer will often spot worn grommets and replace them, sometimes even for free. He/she will also take extra care to mount the racquet properly, use load spreader to protect the weaker racquet head when string at high tensions. He/she will also make sure the clamps are adjusted properly so strings will not slip or get crushed. Just my two cents, please feel free to add more
some more on the "mechanical" side of stringing: http://www.badmintoncentral.com/forums/showthread.php/123933-Pulling-two-strings-at-a-time and then some a bit more than mechanical. stringer who do this will go above the "checklist" to produce a truly better string job. http://www.badmintoncentral.com/forums/showthread.php/123469-main-cross-ratio-explain-this
stringing is partly following a checklist of instructions, and partly science and art. those who can follow a checklist of items will produce a stringjob that look decent and professional. that's important. but doing so doesn't guarantee a "quality stringjob". a truly quality stringer will, through analysis or experience, understands the interaction between strings, know what order/sequence of tensioning works best, and what tensioning pattern to use. they might or might not use the fanciest machine nor do they always remember to replace that slightly worn grommet, their pattern may not look like Yonex's or anybody elses, and may not be the most expensive in town. but once you make the first hit with the racket you realized he has has done something special with it. those are the stringers who stands out among the crowd and the ones you should hold onto at all costs.
Most 6 point machine are trouble. Six points touching the racket but only two point carrying the load, other four point is outside the frame to hold it down. I saw few rackets developed hair line crack between top two grommets,right at where the support is. If you don't see a load spreader on a six pointer, run away. I string more than 100 rackets a year.
A good machine won't make a bad stringer good; a bad machine won't make a good stringer bad. I judge string jobs on a three-tier basis: Adequate: no mis-weaves, tension correct, knots not falling into grommets or coming loose, frame symmetrical left to right. Good: all strings straightened, racket length within 1-2 mm of unstrung. Excellent: no crossovers, knot tails cut flush.
Those who knows about stringing will appreciate this. However, the masses only knows Yonex pattern. It's funny that I come across beginners commenting about a "bad" string job just because the knots are not at the "proper" place.