How To: Bump Pin Tumblers
1. Timing: This is when you want to apply turning pressure to the key. Try to rest your finger on the key with no tension, but the instant the bump hammer hits the key, apply a small amount of pressure. Not to much or to little, more details later.
2. Pressure: This is how much pressure you want to apply turning the key. I usual start light, and increase. Never apply to much pressure or your key will break, or bend.
3. Force: This how hard you wanna hit the key. Never slam the key, it will just bend the key. Start light, and increase force, till you find a good amount. Some locks will respond better to very light force, some will require mildly harder taps.
Additional Tips:
You must combine all three of the above factors for success.
A bump hammer will increase your success, by alot.
Steel Blanks work best, due to not deforming over time. (Credit To JoshuaCodyWilson, on this tip.)