At the risk of sounding immature or even psycho, I have to ask; how much force would it take to break a man's hand with just pure grip strength when shaking hands?

(Obviously this depends on certain variables: size/strength of the other guy, whether his hand is tensed for manly handshake or relaxed for a pussy, "limpfish" handshake. For the sake of this question, lets assume he's an average 5'11" , 175 lb guy giving a relatively decent handshake)

I've already mastered the level #1 Captains of Crush griper and just placed my order for the #2. I just wondered at what point I could potentially do this. (appearantly you can crush a raw potato once you master #3)

For reference:

# 1 = 140 lbs

# 1.5 = 167.5 lbs

# 2 = 195 lbs

# 2.5 = 237.5lbs

# 3 = 280 lbs

# 3.5 = 322.5 lbs

# 4 = 365 lbs

If anyone could help answere this I'd greatly appreciate it. Thanks!