Hello Lee_shanahan
firstly this is not an impartial post, I did a few years ago have a link to the company which invented the original commando wire saw (the new version with the black plastic covered loops and wrist straps was my design) however I think this would be informative with regards to the topic of this thread and I have asked the Moderators permission to post it
The wire saw is not particularly good for use on live or green wood and I certainly wouldnt recommend it for that function, it binds quickly and snaps easily under these conditions, but its important to remember that this is not what it was originally designed for.
it is intended to be hidden in your clothing (sewn into the hem of your jacket or concealed in the sole of a commando boot which is how it was originally stored) and utilised in an escape and evasion scenario to cut the sort of wooden fence posts that surround a temporary POW camp, giving POWs the opportunity to escape early on before they are transferred to a more secure prison facility.
it will normally cut though more than 15 cured fence posts (4" X 4" thick) before it dulls and no longer cuts efficiently anymore, which, hopefully would be enough to see them free and running.
I believe that misguided marketing has lead to the myth that this is an efficient tool for cutting green wood and the subsequently poor reputation of the wire saw.
The other myth about the wire saw is that is breaks because of heat build up and/or wear because of the soft composition of the wire strands this is not normally the case, if it were the wire saw would be unable to cut mild steel as in this video and picture of it cutting 2mm thick angle iron
The cut is 8mm long, at this point the saw dulled to the point that it became difficult to maintain a sawing action without it sticking.
Here is some important info about wire saws:
they were originally designed for cutting cured wood such as fence posts, not green tree boughs. It will cut a standard size 4 by 4 fence post around over 15 times before it dulls, under these conditions it is very unlikely to break.
Whilst it will cut mild steel its slow going and you cant cut very far before you dull the saw
The wire saw is a disposable item, it is design to be used once under E & E circumstances and disposed of. Durability is sacrificed for concealablity because if you cant hide it, you cant use it!
It does not normally break because of heat build-up or wear whilst cutting cured wood or mild steel, it will however break easily if used on green wood due to binding caused by the moisture content of green wood
Like all tools there is some element of correct technique in its use
Its probably not much use for bushcraft unless you foresee yourselves being captured and held by zee Nazis :BlueTeamE
for bushcraft you are much better off with a bucksaw blade and the knowleadge to build a bucksaw frame.
Unless you have one of these which was designed for SOE to cut down Telegraph poles with!:
those are large floor tiles instead of standard wall tiles if thats throwing your size perspective off and this a pocket chain saw in the middle for size comparision:
its razor sharp too!
but seriously, unless your a 'super secret laser guided ninja' in your spare time, your still better of with a bucksaw for bushcraft
Please note that these are my opinions and views, which are not necessarily those of the manufacturers or resellers of wire saws.