Anything is possible if you put your mind and energy into to it. Do you want to have accurate tension? What is the tension you want? Are you stringing a expensive racquet? How much time are you willing to spend? I just would not recommend stringing without a machine. A while back, a BF member actually build a stringing machine himself. Do a search on it.
Yes, it's possible. I remember my first Yonex racquet Cab 9 bought in 1986 was string using bare hand. Being a naive kid of 12 years old, the stringer said it's better that using any machine. In 1992 I bought a pro ace racket from the same stringer, and yes he strung it manually as well. After long leave of playing due to my study and already work for 6 years, I purchased a Yonex Ti-7 light. Due to my long absence, I've got no clue when the shop asked me what tension do I want. The sales person start scratching his head when I mentioned about the manually stringing I exprienced. Boy, now I realised how 17 years do make a lot of difference!!!
It is possible to string without a machine. However, the resulting tension will be low, pretty hard to produce a high tension without a machine. Regarding consistency: In general, stringing without a machine will yield a non-consistent tension. However, with a very experience stringer who has used this method for a long time, the tension can be more or less consistent. Remember that using a machine does not guarantee tension consistency too because it depends on the stringer's (as in person) technique. I have seen stringers who use a machine produce a non-consistent tension. Cheers.
It is possible to string without a machine. I remember when I strung my wooden racket when I was a teenage (13). I still have friend strings him own NS8K racket without machine at 25 Lbs.
Yes, it's possible, but definitely require higher lvl in stringing skill and experience. However, even if with the proper tools, it's quite hard to get to high tension w/o using a machine.
with a minimum of tools, you can string your racquet. each tool you add makes the job that much easier and more consistent, but in a pinch you could do it simply with a wooden dowel. 1. frame support you could get away with no frame support, although unless you have the proper technique, the frame will likely change shape. as a minimum you could try using a metal rod that you can set to the frame size and this can help with preventing head changes. 2. tensioning mechanism a simple wooden dowel can work to tension the string. with stringing machines, there are drop weight, cranks or electric tensioners that does the job for you. a cut-off handle from an old racquet will certainly do the trick. 3. holding string tension you could use awls or even wooden picks that can be inserted in the grommet once the string is tensioned, and that would be sufficient pressure to hold the string tension without any significant loss of tension. next step up would be using a flying clamp, and this makes the job a bit easier, although if you are stringing the racquet free-hand, the flying clamp can sometimes get in the way.