It's pretty simple - it's just a priority list.
Concentrated Strike, Body Blow, Smashing Blow, Body Blow, repeat is possible around 127% Haste.
Concentrated Strike, Body Blow, Smashing Blow, Quick Strike or Focused Burst (Quick Strike is better in raw DPS by a good bit, Focused Burst gives you a ranged option on runners, I would recommend NEVER taking both powers together), Body Blow (you can leave this last one off if your haste is getting high) otherwise. 
Awesome, thanks. I'll probably go for a high recharge build so, the first chain looks good. I'll look into that on the builder, i'll probably end up taking the ranged attack as i play claws and spines usually, so i'm used to having one.
Dark armor lover.
The Claws/DA Scrapper guide.
The range isn't that great - 40 feet - and Quick Strike is very effective at building up Power Siphon charges fast, so it's actually a choice to consider deeply. If you're using an IO set of level 40 or higher, though, you can usually stick in a vanilla range IO to give Focused Burst a decent range of about 50 feet.
Repulsing Torrent is easy to get up to 60 feet, so it is also an option.
I found several threads about KM but none about attack chains in details so... what would be the best attack chains for KM ST dps ? And what kind of recharge needed for each ? Basically i'm thinking about rolling one, and i have no idea about the set itself, how it plays out, and what kind of powers i should take/skip.
Thanks in advance !
Dark armor lover.
The Claws/DA Scrapper guide.