The player of this SG has a heavy right hand attack and was having issues regularly breaking strings.  When someone is having string break issues, I always ask them where they are breaking.  Near the nut?  Bridge?  This one was breaking them at the bridge.  First thing addressed was the saddle slots.  They were pretty gnarly with all kinds of junk and burrs.  Once they were dressed I moved on to the stopbar.  Originally it was tightened down flat to the body.  This was causing a significant break angle of the strings over the bridge and I raised it to allow the strings to decrease their downward force on the saddles.