Is making this illegal in new york?

I live in new york and i am making my very own spring powered pen gun. It shoots thumb taks (aka push pins) to subdue people that are a threat to me or are chasing me etc or to scare the pants off my friends. this is not a projectile propelled by explosive force, and poses no threat to me, the user. It is not fatal, nor able to cause any injuries not fixable with a bandaid. It just hurts like hell. Like a paper cut. Sorta ;D Is this legal? It will be concealed at all times and will not be drawn out in public unless i am threatened.