I wanna put a Locking nut on my guitar, If i put it on, My guitar doesn't have grover tuners, So if i put it on and lock it, will the tuning go up a half step, I heard someone saying if you have a locking nut with no locking tuners, that the tuning will go up a half step.

Is this true?
sometimes, if u got good tuners even if its non locking, it should be able to hold tune.

is ur guitar equipped with a trem or not? if not, it'll be really difficult keeping in tune with a hardtail and a locking nut.
im not familiar with strat trems but u could try a roller nut.

why do u want a locking nut anyway?
^^^Asking the same question too. Locking nuts are bothersome and a pain when it comes to changing strings. If you don't have a FR trem bridge...you shouldn't worry about tuning problems...just get some better tuners....or even locking tuners. Locking tuners, in my opinion, would be a better bet than a locking nut. I had a JEM that I sold about a month ago with a Locking nut and FR trem. I hated when it came time to change strings...it was so painstakingly tiresome!!