Originally Posted by Rev.Chuck
My corded Dewalt 4 1/2" angle grinder with a cutting blade on it would do it in under thirty seconds*
* This is a guess, it will go through 5/16 hardened chain as fast as you want, truly like a hot knife through butter. Of course it is corded so you need to park your bike near an outlet.
"Cutting times" vary widely depending on the quality of the steel involved. Kryptonite uses very high quality steel for its New York lock and its Fahgettaboudit chain, compared with the "industry average".
When "Cycling Plus" used a portable, battery powered cutting disk (the type used by actual street crooks...not the "heavy duty" equipment used for dismantling bridges) on some 13mm shackles, they were able to cut one in 22 seconds. Another took 76 seconds. Another took 149 seconds.
The Kryptonite New York Lock, with a 16mm shackle took over five minutes per shackle. It was necessary to cut two shackles to open the lock, which took over ten minutes total. No crook is going to stand on a busy street corner with a noisy power tool, working for ten minutes on a Kryptonite, when the next bike on the rack can be opened in 22 seconds, or less. (One U-lock failed in five seconds...that is the bike a "smart" crook is going to target.)